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- Front Matter: Volume 7658
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Front Matter: Volume 7658
Front Matter: Volume 7658
Show abstract
This PDF file contains the front matter associated with SPIE
Proceedings Volume 7658, including the Title Page, Copyright
information, Table of Contents, Introduction, and the Conference Committee listing.
5-1
Dependence of silicon thin-film growth characteristics on substrate temperature
Show abstract
Silicon thin-films are fabricated on quartz substrates in the substrate temperature range 500~600 °C by electron-beam
evaporation (EBE). Scanning Electron Microscopy (SEM) is employed to characterize the surface morphology of the
films and measure the grain size. It is found that, there is an optimum temperature for getting large grain size. The X-ray
diffraction (XRD) results show that the preferred crystallographic orientation on quartz wafer is (111). Raman spectra
demonstrate the crystallization condition of the films and the crystalline volume fraction are calculated. The results
indicate that the growth characteristics of the films depend significantly on the substrate temperature. Silicon thin-films
are observed to be amorphous under the temperature of 560 °; above this temperature, they are polycrystalline. In other
words, 560 °C is the critical temperature of the films transforming from amorphous silicon to poly-Si. The optimum
temperature at about 580 ° for the growth of the film on quartz substrates is obtained. The films exhibit the largest grain
size, highest value of crystalline volume fraction and the best structural quality when the substrate is kept at this
temperature.
Assess image blur in photoelectric imaging system
Show abstract
The difficulty for no-reference image quality assessment is the lack of the information of the reference image. With the
analysis of the mathematical model of the photoelectric imaging system and the reason for image blur, a method is
proposed for constructing reference images, and at the same time the Structural Similarity index is introduced into noreference
image quality assessment. A novel no-reference image quality assessment index called No-Reference
Structural Sharpness is then proposed for quality evaluation of blurred images. This method constructs a reference image
by a low-pass filter, and assesses the image quality by computing the structural similarity index between the original
image and the reference one, thus considering the mathematical model of imaging system as well as the advantages of
Structural Similarity index. The experimental results show that the new index is well in accordance with quality
assessment results of both subjective evaluation and full-reference methods.
Photoluminescence and photovoltaic performance of poly3-octylthiophene and poly3-alkylthiophene
Show abstract
Photoluminescence (PL) and photovoltaic (PV) performance of poly3-octylthiophene (P3OT) and poly3-alkylthiophene
(P3DT) were studied in detailed. The two kinds of polymer can exhibit strong deep red emission peaking at 688 nm for
P3OT and 675 nm for P3DT under blue light excitation, the effective excitation wavelength is about 462 nm. The
dynamic process of exciton induced by light excitation strongly determined the PL and PV characteristics. From the PL
excitation spectra of P3OT and P3DT, it can be seen that there are wide and intense excitation wavelengths in the visible
light range. Two kinds of polymer solar cells based on P3OT or P3DT doping with PCBM were fabricated and the
characteristics of OPVs were measured, the short current density (Jsc) and open circuit voltage (Voc) are 0.84 mA/cm2,
0.95 mA/cm2 and 180 mV, 270 mV, respectively.
Research progress on optical wireless communication at Xi'an University of Technology
Show abstract
Optical Wireless Communication (OWC) adopts laser beam as the carrier to deliver the message. It combines with the
advantages of Microwave Communication and Fiber Optic Communication. The key technologies of OWC system
includes source coding, channel coding, laser diode modulation, auto-alignment and channel. In this paper, the research
progress on OWC in Xi'an University of Technology is introduced. The research on source coding involves in baseband
modulation, frequency modulation, OFDM transmission and vertical layered space-time codes. The research on channel
coding includes RS codes, Turbo codes, LDPC codes and so on. And the adaptive coding method is analyzed to meet the
different channel characteristics. Propagation performance of laser is studied and bit error rate (BER) is measured under
various weather conditions of rainy days, snowy days, foggy days, hazy days and so on. The experiment results show
that applying channel coding methods can improve the system performance of OWC, especially under rainy, snowy,
foggy weather conditions, the BER after decoding is up to 10-6. Based on many years of research, the technologies of
MIMO, OFDM and space-time coding are proved to be the key technologies that need to solve in OWC.
Energy transfer from both triplet and singlet energy levels of PVK to DCM2 induced by heavy-ion
Jiaxiu Luo,
Lixin Xiao,
Zhijian Chen,
et al.
Show abstract
The energy band of red light-emitting materials is usually very narrow, which easily results in non-radiative
recombination of excited states. There also exists concentration quenching effect due to strong π-π interaction. To
avoid this, host-guest doping system is mostly used. On the other hand, the ratio of singlet and triplet excited state caused
by recombination is 1:3. In comparison with the fluorescence (singlet to singlet), phosphorescence (triplet to singlet, but
spin-forbidden) is much weaker, and the quantum yield is much lower. To enhance it and make full use of triplet excited
state energy, heavy atom effect is commonly used to induce strong spin-orbital coupling leading to mix of singlet and
triplet and release the forbidden triplet energy. Based on this, we fabricated polymer light-emitting diodes adopting
polyvinylcarbazole (PVK) as the host and a red fluorescent dye, 2-{2-methyl-6-[2-(2,3,6,7-tetrahydro-1H,5H-pyrido[
3,2,1-ij]quinolin-9-yl)-vinyl]-pyran-4-ylidene}-alononitrile (DCM2), as the dopant, and materials containing
heavy-ion, kalium idode (KI) and bromo-carbazole, as energy transfer bridge to obtain complete energy transfer from
excited states of both singlet and triplet energy level of PVK to ground state of singlet of DCM2. We found the current
density of devices with heavy-ion materials were higher than device without it, and the weak blue emission from PVK
host, existing in device of PVK:DCM2 device, can not be observed in electroluminescence spectra of device with heavy-ion
materials, which indicates a complete energy transfer from both triplet and singlet energy levels.
SAW ethanol gas sensors based on cryptophane-A sensitive film
Show abstract
Surface acoustic wave (SAW) devices have been widely used for various chemical sensing applications because the
sensor signal can be detected by simple and inexpensive electronics. The interactions between target analyte and the
sensor surface cause changes in the mechanical, electrical, dielectric properties of the sensing coating deposited onto
acoustic transducer. The changes in these properties will lead to changes in the velocity and amplitude of wave modes,
which can be measured by frequency and insertion loss (IL) changes when the acoustic element is realized as a delay line
or resonator. Among the different sensing coatings, the supermolecules are of considerable interest because the host
molecules can be thought as original receptors allowing a specific recognition of guest molecules based on "key-lock"
system. In this paper, SAW ethanol gas sensors that utilize the supermolecule of cryptophane-A as sensitive layer have
been studied. We synthesized cryptophane-A from vanillyl alcohol using a double trimerisation method and deposited it
on the SAW devices to fabricate cryptophane-A based SAW gas sensors. The SAW frequency and insertion loss (IL)
were measured using a network analyzer. The frequency shift as the response of the cryptophane-A based SAW sensors
to different concentration ethanol was measured at room temperature. It is found that the cryptophane-A based SAW
sensor has high sensitivity and good reproductivity to ethanol. The frequency response increased linearly with the
concentration of the ethanol.
Realization of p-type conductivity in ZnO by (N, Ag) dual acceptor codoping: a first-principles study
Show abstract
Ag monodoped, N monodoped and (nN, Ag) codoped ZnO have been investigated by the first-principles calculations,
where the formation energies and ionization energies of various complexes and the electronic structure for 3N-Ag
complex are studied. The calculated results are that N prefers to substitute O site, and Ag substitutes Zn site under the
most growth condition, which indicate NO and AgZn all act as acceptors. Meanwhile, it's shown that N-Ag, 2N-Ag
complex contribute little to p-type conduction because of the relatively higher ionization energy. However, 3N-Ag
complex may have the lowest ionization energy among various complexes, while the formation energy of 3N-Ag is
lower than that of N monodoped, Ag monodoped, N-Ag and 2N-Ag complex under the Zn-rich condition, which
indicates that 3N-Ag complex is energetically favorable for the formation of p-type ZnO. Furthermore, by studying the
electronic structure of 3N-Ag complex, it may generate an additional impurity band above the valence band maximum of
ZnO. It is found that NO generated holes around the top of the valence band, and at the same time, N 2p states hybridized
with 4d states of AgZn at the Fermi energy, and the hybridization lowered the repulsive interaction between the two dual
acceptors, which enhance the concentration of impurities and the stability of the system, indicating that the dual
acceptors evidently improve p-type conductivity of ZnO. Thus, it is found that 3N-Ag complex is the better dopant
configuration. That can gain a better quality p-type ZnO under the Zn-rich condition. Our theoretical results are
consistent with the experiment results.
Electrical and optical properties of amorphous vanadium oxide thin films deposited by DC magnetron sputtering
Show abstract
In this work, vanadium oxide thin films were grown on glass slides by using reactive direct current (DC) magnetron
sputtering from a vanadium target in an Ar+O2 atmosphere. It was found that the surface morphology, electrical and
optical properties were strongly affected by the deposition temperature. X-ray diffraction (XRD) and scanning electron
microscopy (SEM) were used to characterize the structure and surface morphology of the samples. The structures of
these films showed amorphous nature according to the XRD patterns showing no sharp diffraction peak. Measurements
of SEM indicated the smooth surface of film deposited at low deposition temperature and rough surface at relatively high
deposition temperature. In addition, these surfaces showed no obvious crystalline morphologies, which supported the
XRD results. Electrical measurement indicated that the square resistances of films showed an exponential increase from
33 kΩ/square to 46 MΩ/square as the deposition temperature decreased from 320 to 160 °C, and that the square resistancetemperature
curves of films exhibited typical semiconducting behavior. The investigation of optical properties of films in
near-infrared range indicated that transmittance varied from about 95 % to 55 % when the deposition temperature
elevated. In the ultraviolet-visible range, optical transmission measurements revealed that films showed distinguished
transmission spectra when they were grown at different deposition temperatures. In the range of 300 to 400 nm, a
transmittance shoulder was observed in the spectra, and this shoulder enhanced when the deposition temperature
increased. On the other hand, a transmission enhancement at 530 nm disappeared after the deposition temperature
exceeded 240 °C.
Optimizing the growth condition of optoelectronic material (ZnO film) by imaging technology
Jun Wang,
Shi Pan,
Yi Zhang
Show abstract
Using reactive radio-frequency magnetron sputtering technique, ZnO films are grown on Si (111) substrates with ZnO
buffer layers deposited under different temperature with optimal condition of working pressure, sputtering power, flux of
gas and sputtering time. In order to study the influence of ZnO buffer depositing temperature on the characteristic of the
ZnO film, atomic force microscope, X ray diffraction, Raman spectroscopy and photoluminescence spectrum are used to
analyze the morphology, growth orientation, Raman spectrum and optical properties of the ZnO films. It is concluded
that the optimal depositing temperature of the ZnO buffer for the growth of the top ZnO film is 350 °C.
Effect of variable substrate temperature for SrTiO3 thin films using pulsed laser deposition
Show abstract
In this paper, the high temperature solid state reaction method was applied to the preparation of SrTiO3 ceramic target.
The phase of the target has been researched in experiment by X-ray diffraction (XRD). We found that solid state reaction
has achieved completely. Then SrTiO3 thin films on MgO (100) substrate were manufactured by PLD using the
triple-frequency harmonics of pulsed laser Nd: YAG. The thickness of the SrTiO3 thin films was measured using a stylus
profiler. Their microstructure and surface morphology were analyzed using X-ray diffraction (XRD) and atomic force
microscopy (AFM). Their optical character was characterized using optical transmission spectrum. Additionally, X-ray
photoelectron spectroscopy (XPS) spectra were used to characterize the surface chemical composition of the
SrTiO3 thin film. In accordance with the above text result, the relation between the substrate temperature and the SrTiO3
thin films' the structure and character was analyzed and discussed. With increasing temperature of the substrate, film
grain size gradually increased and then smaller. The optimized substrate temperature was found to be 700 °C at which the
STO films' structure could uniformly dense. The STO films present a low optical absorption in the 400~1000nm
wavelength range, and the substrate temperature is not the main reason for the impact of the optical absorption. The
optical band gap energy was found to be about 3.5 ~ 4.0eV for the STO thin film. The valences of the three elements (Sr,
Ti, and O) in the STO film prepared by PLD are 2+, 4+ and 2-, respectively.
Numerical simulation of multilayer organic light-emitting devices
Hansong Gao,
Haibo Rao,
Yue Hu,
et al.
Show abstract
A numerical model of multilayer organic light-emitting devices (OLED) is presented in this paper which was consisted
of electrical and optical model. The electrical model is based on the drift-diffusion equations. Multilayer organic
heterojunctions were mostly considered in this work. A simulation course was programmed with MATLAB. The I-V
characteristics obtained show a good agreement with experiment data. The optical model utilizes the optical interface
effect, the EL spectrum was calculated with Alq3 thickness of 40 nm, 50 nm and 60 nm, respectively. The Brightness-
Voltage characteristics was simulated, the results and experimental data in the literature are in good agreement on the
magnitude.
The low-cost preparation of pyramid-like texture ZnO thin films and the application as a front electrode in hydrogen amorphous silicon solar cells
Show abstract
The pyramid-like texture ZnO thin films were usually synthesized by MOCVD or etching the as-prepared RF magnetron
sputtering films, and the expensive equipment cost and uncontrollable acid etching, respectively are two main
disadvantages both the MOCVD and RF magnetron sputtered. In this paper, the pyramid-like texture ZnO thin films
were prepared through a low-cost two-step process, firstly, a seed ZnO:Al layer was coated on the quartz substrates by
sol-gel method and subsequently a ZnO thin film was fabricated by RF magnetron sputtered. It is shown from the XRD
and SEM results that the ZnO thin film has (101) preferential orientation with a pyramid-like texture. According to the
measurement results of ZnO films' resistivity and UV-Visible transmission spectra, the lower resistivity of 10-3 Ω•cm
and optical transmission of higher than 80 % were obtained for these ZnO films. It has shown that the pyramid-like ZnO
thin film is a potential transparent conductive film used in amorphous silicon solar cell for front electrode, and the cell
performance is comparable advantages for that of ITO conductive film.
5-2
Substrate temperature influence on the properties of InGaZnO thin films grown by PLD technique
Show abstract
In this paper, the effects of substrate temperature during film growth at relative high temperature have been reported. The
IGZO thin films were fabricated by means of pulse laser deposition (PLD) with the InGaZnO (In2O3: Ga2O3: ZnO=1: 1:
8 mol %) target. The substrate temperature altered from room temperature (RT) to 800 °C. The product thin films were
characterized rigorously by X-ray diffraction (XRD), atomic force microscopy (AFM), UV-VIS spectrometer, Halleffect
investigation and X-ray photoelectron spectroscopy (XPS). The IGZO films was with smooth surface, high
transmission in the visible spectral range (about 75-92 %), carrier mobility > 8.0 cm2/(V·s) and carrier concentration at
about 1018 cm-3. Finally, the character changes influenced by temperature were obtained from analysis results. This task
may benefit to a flat panel display in the process of thin film transistors(TFT) fabrications and improvements.
Polymer PSQ-L notch filter fabricated by simple nanoimprint process
Jie Teng,
Xiuyou Han,
Mingshan Zhao
Show abstract
Polymers are emerging as an important material in the field of integrated optics. In this paper, we propose a simple
method to fabricate polymer waveguides by using a novel polymer PSQ-L. The high index polymer PSQ-LH is used as a
core material and the low index polymer PSQ-LL is used as a cladding material. The waveguide circuits are replicated by
using a UV-based soft lithography process. Unlike in conventional imprint processes, the imprint step for structuring is
done first on the cladding layer rather than on the core layer and is followed by a spin-coating step to fill the imprinted
features with core layer material. The all-polymer microring resonators are fabricated by this method. The coupling
efficiency between the straight waveguides and the ring is adjusted by controlling the gap distance between the straight
waveguides and the ring. About 20dB extinction ratio and a high Q factor of 3.4×104 is obtained for critically coupled
PSQ-L ring resonator.
Effect of triplet energy and transporting property of electron transporting material on iridium complex yellow phosphorescent organic light-emitting devices
Show abstract
Balanced charge carrier and appropriate exciton confinement are considered as the key factors for the realization of
highly efficient and stable organic light-emitting devices (OLEDs). An effective way to reach a loss free hole-electron
recombination and exciton leakage is to use suitable electron transporting layers (ETLs). To investigate the influence of
triplet energy and electron transporting properties of ETLs on the performance of iridium complex yellow
phosphorescent OLEDs, we fabricated three devices based on bis[2-(4-tert-butylphenyl)benzothiazolato-N,C2']iridium
(acetylacetonate) [(t-bt)2Ir(acac)] doped 4,4'-bis(carbazol-9-yl) biphenyl (CBP) host by using 2,9-dimethyl-4,7-diphenyl-
1,10-phenanthroline (BCP), 1,3,5-tris(N-phenylbenzimidazole-2-yl)benzene (TPBi), and 4,7-diphyenyl-1,10-
phenanthroline (BPhen) as ETLs, respectively. It was found that there was no apparent correlation between the device
efficiency and the triplet energy of ETLs. Instead, device efficiency was determined by the electron mobility of ETLs
only. With an optimized device using BPhen as ETL, a power efficiency of 23.1 lm/W and a current efficiency of 28.0
cd/A at 0.08 mA/cm2 were achieved, which was much higher than that of the control devices (7.5 lm/W for BCP-device
and 8.5 lm/W for TPBi-device). The improved efficiency was attributed to that BPhen had the highest electron mobility
and provided better charge balance in the hole-dominant devices. Moreover, the EL spectra of three devices showed no
obvious difference with a light emission from iridium complex peaked at 562 nm and a shoulder peak at 600 nm. This
indicated that no matter BCP, TPBi or BPhen acted as ETLs, the (t-bt)2Ir(acac) triplet exciton can be confined within the
emissive layer effectively.
Solvothermal synthesis of platinum nanoparticles and their SERS properties
Show abstract
The controllable preparation of platinum nanoparticles with defined shapes, including sphere, octahedron, octapods and
tetrapods, was realized by varying the concentration of NaNO3 in the solvothermal process. NaNO3 plays a critical role
in synthesizing Pt nanoparticles with different shapes. These Pt nanoparticles were self-assembled on glass substrates to
study the influence of metal nanoparticles' shape on their SERS enhancement using 4-mercaptopyridine as molecules
probes. Thanks to the enhanced local field effect around their sharp corners and edges, those Pt tetrapods exhibit
enhanced SERS properties than those particles with other shapes.
Theoretical and experimental demonstration of phase locking technology by utilizing cubic susceptibility medium
Show abstract
A novel proposal for phase locking based on cubic susceptibility medium has been theoretically proposed and
experimentally demonstrated. The expression for phase difference between injected waves is yielded from the coupled
wave equations, which implies the phase noise can be eliminated through low-efficiency four-wave mixing (FWM).
Beat-note signal and autocorrelation trace heterodyned by the injected waves with small and large detune are adopted to
assess phase locking effect, and they are monitored by electrical spectrum analyzer (ESA) and autocorrelator (AC)
respectively. Moreover, the influence of polarization state on phase locking is also investigated, and experimental results
match well with the theoretical predictions.
Steady enhancement of organic solar cell performance by doping phosphorescent iridium complex
Show abstract
Efficient organic photovoltaic cells based on a phosphor of (t-bt)2Ir(acac) were demonstrated. Also, the photovoltaic
performances of organic solar cells with a device structure of ITO/(t-bt)2Ir(acac):CuPc (doping rate R=0 and
0.25)/C60/BCP/Ag were determined based on the current density (J)-voltage (V) curves of a series of devices. The
absorption spectra of doping layer (t-bt)2Ir(acac):CuPc and C60 films on quart substrates were measured to gain a direct
insight of absorption ability of dopant (t-bt)2Ir(acac). Then, revised optical transfer matrix theory was adopted to study
inner effect of dopant (t-bt)2Ir(acac) on the enhanced device performance, which shows that (t-bt)2Ir(acac) dopant
increases the light density of doping layer by reorganizing the light distribution inside organic films. However, the light
absorption efficiency ηA of device with R=0.25 does not improve. According to the unchanging value of open circuit
voltage VOC and similar fill factor FF, the assumption that two devices with R=0 and 0.25 possess similar charge carrier
collection efficiency ηCTηCC can be made. Thus, the inner enhancement of exciton diffusion efficiency ηED is discovered
with the assistance of longer triplet exciton diffusion length of (t-bt)2Ir(acac).
The application of ALD process on special fiber
Show abstract
The film thickness and the composition of the fiber can be controlled by ALD (Atomic Layer Deposition) process at
atomic level. Therefore, a special fiber with the structure of alternating deposition of doped Nano-semiconductor
materials (such as PbS, InP etc.) and SiO2 can be manufactured by ALD process. In a word, this would not only change
the manufacturing technology of fiber, but also greatly changed the structure of fiber. In this paper the Band-gap energy
and absorption wavelength is calculated for different nano-particle size by the influence of Quantum Size Effect.
Considering the 1550 nm wavelength used widely in optical communication, the particle size is calculated, which is used
in a simulated structure of the special fiber. Then Based on the simulation of the distribution of optical field, we draw a
conclusion that the light field intensity in the special fiber is lower than the single fiber. Therefore, a high-power
pumping light should be added if the special fiber is used as amplifying fiber.
Research on high-speed single photon detector
Show abstract
Single-photon detector based on an InGaAs avalanche photodiode is one of hot research on the quantum photon, and is
one of the key technologies on quantum communication and quantum image. It is widely used in applications as high
sensitive photon spectrum, high speed optic measurement and so on. A suitable delay and comparator with latch function
circuit are used to prevent positive and negative transient pulses from influencing the detection of true photon induced
avalanches. A dead time modulation feedback control circuit decreases the after-pulse. Especially, ECL difference circuit
is the key of high speed single photon detector. In addition, the detector uses the hot tube fan-cooling method. From the
performance test, the lowest temperature reaches -62°C, the minimum gate pulse width is 2ns (Full-Width-Half-Max,
FWHM) and the dark counter rate is 2.5×10-6 ns-1 with a detection rate of 10MHz when the quantum efficiency is more
than 10%.
Simple defogging method for outdoor images based on physical model
Show abstract
Images of scenes acquired in bad weather have poor contrasts and colors. In this paper, we exploit the idea of interactive
method and recover the images based on physical model. First, a simple method is proposed to estimate the scene depths.
Second, the parameters in the depths model can be obtained automatically from a single image. Experiments show that
our method can remove the haze effectively. Especially, it is easy to serve for the practice.
Quantitative analysis on flyback region problem of 1D transmissive liquid crystal optical phased array devices
Show abstract
In practical application of Liquid crystal optical phased array (LCOPA) device, diffraction efficiency and deflection
range are two important performance parameters, which should be improved further more. Both diffraction efficiency
and deflection range are directly related to the width of flyback region. Therefore, the flyback region problem was
analyzed quantitatively in this paper. According to elastic continuum theory of liquid crystal and crystal optics theory,
we calculated LC director and its phase delay profile. Then we analyzed quantitatively the influence of device parameters
including electrode size, alignment layer thickness and LC cell thickness on the width of flyback region. Results show
that there exists a critical value of electrode size. When electrode size is larger than this critical value, the width of
flyback region increases nearly linear to the increase of electrode size. The width of flyback region is not sensitive to
alignment layer thickness and increases monotonously with the increase of LC cell thickness.
5-3
Nano-optical microscopy: now and its industrialization
Show abstract
It is a review about the industrialization of Nano-Optical Microscope (NOM, also referred to as the Near-field Optical
Microscope). Two comparisons of AF/PSTM (Transmission Mode) with the first generation commercial A-SNOM and
AF/RNOM(Reflective Mode) with A-RNOM have discussed. The commercially used A-SNOM can only obtain a
transmissivity image of A-SNOM-T(x,y), but AF/PSTM can obtain the separating the transmissivity image PSTM-T(x,y)
and the refractive index imge PSTM-n1(x,y). AF/RNOM can obtain the lower contrast reflective index image but ARNOM
cannot. The reason how could Pohl have obtained the first A-SNOM image with a resolution of 20-25nm in
1984 but the commercial A-SNOM-T(x,y) only with the resolution in the 50~100nm range is also discussed. Conclusion
on the proposal of AF/PSTM and combined AF/RNOM may be the best candidate for the second generation commercial
use of NOM.
Study of the transfer function of atmosphere to operation range of IRFPA
Show abstract
There are much more need to characterize and evaluate performance of IRFPA in field. MRTD, MTF, NETD and
operating range R are some of the key parameters of IR devices and used to characterize their performance. Around
of these parameters there are two ways: analysis in theory and test. The research of these parameters in theory can be
used to predict the performance of IR devices and these parameters can be proved by experiments. Whereas these
parameters are hard to be tested in field, their test reports are based on experiment in laboratory. So it is very hard to
explain or predict the test results of IR devices in theory because of the influence of atmosphere. This paper presents
research of transfer function of atmosphere. A model of transfer function with the modified absorption and scatter
coefficient is introduced based on the theory of transfer function. The operating range can be modified by transfer
function of atmosphere. The experiment results show this model can be used together with operating range in some
circumstances. It could be used in the predicting the operating range of IR devices in theory.
Thickness effect and etching implement of silicon substrate of LiTaO3 thin film infrared detector
Deyin Zhang,
Wentian Luo,
Yong Bao,
et al.
Show abstract
The pyroelectric LiTaO3 thin film has low heat capacity, low thermal loss, high pyroelectric response and high possibility
to make infrared detector, so the LiTaO3 thin film infrared detector preparation is considered in this paper. During the
fabricated experiments, the silicon substrate thickness effect on performance of the LiTaO3 thin film device is very large,
and therefore it has been theoretically investigated by using the MATLAB software and by employing one-dimensional
heat conduction equation. The simulation results show the thinner the silicon substrate, the less the thermal loss by
conduction, and thus, the higher the pyroelectric response of the LiTaO3 thin film device. To verify the theoretical
analysis, the LiTaO3 thin film device deposited on the Pt/Ti/SiNx/SiO2/Si(100) substrate with different silicon substrate
thickness are fabricated and the etching process of the silicon substrate have been discussed in details. The experimental
results of the current responsivitiy and the specific detectivity of the LiTaO3 thin film device agree with the theoretical
analysis. The theoretically and experimental results are together determined that, thoroughly etched-off the silicon
substrate is the best method to reduce thermal loss and improve the property of the LiTaO3 thin film device.
Realization of large open circuit voltage in organic photovoltaic cells by introducing a fluorescent dye layer
Nana Wang,
Junsheng Yu,
Yue Zang,
et al.
Show abstract
Small-molecule organic photovoltaic (OPV) cell with a large open circuit voltage (VOC) has been achieved by
introducing 4-(dicyanomethylene)-2-t-butyl-6-(1,1,7,7-tetramethyljulolidyl-9-enyl)-4H-pyran (DCJTB) as donor layer.
In order to obtain large VOC of standard copper phthalocyanine (CuPc)/C60 OPV cell, a very thin layer of DCJTB was
inserted between CuPc and C60. It was found that the device formed multicharge separation interfaces. The VOC of device
with 2 nm DCJTB layer was increased from 0.44 to 0.58 V. Also, the atomic force microscope (AFM) 3D-images of the
donor surfaces were characterize to discuss OPV cell performance improvement. Furthermore, the absorption spectrum
shows that an additional thin DCJTB layer enhances the light harvest capability of the cell.
Electroluminescence performance of organic light-emitting diode with molybdenum trioxide inside hole transport layer
Show abstract
A new structure of organic light-emitting diode (OLED) was fabricated by inserting a thin molybdenum trioxide (MoO3)
layer into hole transport layer (HTL) N,N'-diphenyl-N,N'-bis(1-napthyl-phenyl)-1,1'-biphenyl-4,4'-diamine (NPB). The
device structure is ITO/NPB(10 nm)/MoO3(3 nm)/NPB (30 nm)/tris-(8-hydroxyquinoline) aluminum (Alq3) (60
nm)/LiF(0.5 nm)/Al. The control device is set without MoO3 interlayer. The driving voltage at 100 cd/m2 is only 4.87 V
corresponding to the device with MoO3 interlayer, which is much lower than the control device of 6.40 V. The novel
device also shows higher power efficiency compared to the control device. The improvement of device performance is
attributed to the Charge Transfer complex (CT complex), generated at the NPB/MoO3/NPB interfaces, contributing here
as hole transfer enhancer. Our finding additionally demonstrates the practical applicability of MoO3 as a buffer layer in
OLEDs.
Fraunhofer diffraction of the object with inclined plane
Anqing Zhao
Show abstract
Taking the rectangular hole as an example, this paper addresses the theoretical calculation and experimental observation
of Fraunhofer diffraction field when the object plane is inclined to the system optical axis and compares it with that when
the object plane is perpendicular to the system optical axis. The author finds in the experiment that the diffraction pattern
changes when the object plane is inclined to the system optical axis. The theoretical significance of the paper lies in that
it gives a general expression for Fraunhofer diffraction field. The situation that the object plane is perpendicular to the
system optical axis is only a particular case for the above expression.
The research and analysis of TDICCD dynamic driving design
Yun Cheng,
Tao Li
Show abstract
Compared with ordinary linear CCD, one of the most remarkable advantages of TDI/CCD is that it can work under low
illumination conditions with imaging clearly. Meanwhile, multiple exposures can reduce pixel inconsistency and the
fixed-pattern noise; enhance the Sensitivity and Uniformity of visible light CCD. As a result, TDI/CCD has an extensive
application in the aerospace industry.
To meet the needs of orientation of TDI/CCD's application towards high-speedy, miniaturization and intellectualization,
in this paper,Fairchild Imaging CCD525 is chosen as image sensor,by means of programming on XC2V1000 which is
one type of Virtex-II serials FPGA, using the key technology such as IP reuse,DCM and timing constrain, realized the
functions of real-time adjustment of TDI integration time,number of integration stages,VGA gain and digital quantitative
deviation. The whole system not merely passed the software simulation on ModelSim,and achieved satisfactory effect in
practical application.
Research on accelerometer based on multi-mode interference
Show abstract
A new type of accelerometer is advanced which is based on optical fiber multi-mode interference (MMI). We use a
structure that a multi-mode fiber connected to two single mode fibers as the sensing part of the accelerometer. By
measuring the changes of the output spectrum can get the acceleration. This paper describes the principle of the
accelerometer based on multi-mode interference, and a theoretical simulation is performed. In the experiment a
Piezoelectric Ceramic is applied to simulate the Static Acceleration. The result manifests that this type of accelerometer
has a great dynamic range and a good resolution, also it's easy to fabricate and low cost.
A novel chemically selective siloxane polymer for chemical vapor sensing
Show abstract
A new hydrogen-bond acidic carbosiloxane polymer for quartz crystal microbalance sensors (QCMs) application was
synthesized via O-alkylation, Claisen rearrange, hydrosilylation reaction and functionalized the polysiloxane with
trifluoroacetone groups (TFA). The trifluoroisopropanol functionalized polysiloxane was characterized by FT-IR and
1HNMR. And this novel siloxane polymer was coated onto AT-cut 8 MHz QCM sensors to investigate its gas sensitive
responses to the organophosphorus nerve agent stimulant dimethyl methylphosphonate (DMMP) vapor as well as other
interfering organic vapors. The research work indicated that frequency shifts of the trifluoroisopropanol functionalized
polysiloxane based QCM sensor to the DMMP vapor were completely linear, and with a regression coefficient of 0.9973
in the concentration range of 10-60 ppm. In addition, the sensitivity of the fabricated QCM sensors to DMMP was up to
10.64 Hz/ ppm, and much higher than the other interfering vapors, limits of detection (LODs) of the QCM sensors was
0.28 ppm, thus high selectivity to DMMP was demonstrated in this work.
Investigation of bright spatial solitons in SBN: 75 photorefractive crystal
Show abstract
This work studied the formation of spatial solitons in a SBN: 75 photorefractive crystal by 532 nm continuous-wave
laser beam from a single frequency solid laser. It was found that the behaviors of the spatial solitons varied with
background light. While white light and 632 nm red light are used as background, the solitons perform like first-order
light soliton. The compressed-amplitude, in measured with laser beam's size before and after passing the crystal, is
proportional to the applied voltage of a dc electric field, i.e., they are quasi-steady-state solitons formed in a time
window. However, as the background is changed to an incoherent 532 nm light output from the same laser, the solitons
vary periodically and the compressed-amplitude is not proportional to the voltage of applied dc electric field any more.
In this case, solitons form instantaneously at applied field of 900 V/cm and hold the shape for 7 seconds which is less
than the one with white or red light as background, and then break slowly. We tried to present reasonable explanation for
above observation.
Poster Session
Daytime star detection device using polarization and spectral filtering method
Show abstract
How to see the stars in daytime? A new idea is described here in this paper which uses a combination of two methods:
one is traditional spectral filtering method and the other is a new attempt on daytime star detection--polarization method.
Each of these two method's principle of work, scope of application and limitation on daytime star detection are
introduced in detail; and the advantage of the combination is discussed accordingly. Based on the demand of the daytime
star detection, a device is designed and its optical system and mechanical structure are also analyzed in this paper. At last,
a further discussion of the existing problems and the possible improvements of the current device are presented.
Study of quantitative identification of infrared thermal wave testing based on BP neural networks
Zhang Wei,
Liu Tao,
Yangzheng Wei,
et al.
Show abstract
In order to resolve the problem of quantitative identifying, in pulsed thermography, taking the highest temperature
difference and the best testing time as input, and taking defect depth and diameter as output, made use of BP Neural
Networks to achieve it, and it was done. According to result, when testing value was in area of swatch, identifying
precision was high, and error is less than 3.5%. The feasibility of BP Neural Networks was validated, and it has very
important meaning to quantitative identifying of factual application.
Quantum teleportation and survey technology
Zhiguo Wang
Show abstract
Quantum teleportation is an important component element of quantum information theory and is an effective method to
realize quantum communication. This paper presents the realization method and survey technology of quantum
teleportation, introduces the theory and experiment research process of quantum communication field and its broad
prospect.
Effect of carrier gases on growth of thick GaN films by hydride vapour phase epitaxy
Show abstract
The effect of carrier gas on thick GaN film grown by hydride vapour phase epitaxy on (0001) sapphire substrate has been
studied by double crystal X-ray diffraction (DCXRD), field emission scanning electron microscope (FE-SEM),
photoluminescence (PL) and Hall tester. H2, as carrier, is propitious to two-dimension growth pattern of GaN film, but it
causes production of more defects and impurities. Red shift of band edge emission of PL and a wider FWHM (full wave
at half maximum) of DCXRD appear under H2 atmosphere. N2, as carrier, reduces the content of defects and impurities.
However, the growth interface of GaN forms easily crystallographic facets but not epitaxial (0002) plane, which leads to
appearing of embossed surface. It may gain high-quality HVPE-GaN that H2 and N2 are adopted as carrier gas
sequentially.
Data processing based on 3D measurement system using disparity method
Shuping Yang
Show abstract
A double CCD Camera 3D measurement system, which is based on the Marr vision calculation theory, classical disparity
imaging theory and stereo model, was designed. Method and related techniques have been described in this paper after
analyzing and comparing deferent kinds of 3D testing methods, which provide references for the setting up of hardware
system. Based on both eyes vision model, a set of 3D testing program based on disparity is designed. By analyzing the
sample data: while the confidence is 0.99, the system precision is 0.01mm.
Traceable dynamic calibration for CHAL-010 thermocouple
Show abstract
Thermal inertia and finite heat conduction make the acquired temperature from temperature sensor be not reliable
enough. So, it is necessary to make a dynamic calibration to the sensor. The frequency-response characteristics of high
speed radiation thermometer surpass that of the temperature sensor; therefore it can be used as the reference value to
calibrate the latter and let system error is corrected. The traceable dynamic calibration method is used to calibrate
CHAL-010 thermocouple (manufactured by OMEGA Company). The thermocouple's time constant as well as error
correction value of dynamic temperature measurement is obtained from it. The traceability is accomplished successfully
through unbroken chain of comparisons with appropriate standard at the system.
Time constant measurement of thermocouple by use of modulated laser
Lina Hao,
Xiaojian Hao,
Sanping Jiang,
et al.
Show abstract
A new time constant measurement means of the surface temperature sensor is proposed, in which a high frequency
modulated high power CO2 laser acts as the driving source. The measurement system is designed and practiced in
thermocouples with different temperature ranges. It is proved that the system can be used to measure transient surface
temperature sensor which be with a time response from the sub-millisecond level to the second level, and the temperature
provided by the driving source can range from the room temperature to the high temperature.
The design of mirror's temperature control system of three Antarctic Schmidt Telescopes
Show abstract
Preliminary site testing shows that Antarctic inland Dome A is likely to be the best astronomical observatory site on the
ground, Chinese first Antarctic astronomical equipment CSTAR has been successfully run Dome A. Three Antarctic
Schmidt Telescopes (AST3) is the next important Antarctic astronomical equipment, one of which will be mounted
Dome A. In the year of 2010, and the three will be installed Dome A finally. Because of the very low temperature and
saturation vapor pressure, and the temperature gradient changes fast near the ground layer at Dome A, the mirror is easy
to be frosted, which is one of difficulties to AST3.Indium Tin Oxide (ITO)is an N-type semiconductor material, because
it has few resistors, good light transmission, good weather resistance, small environmental impact, low cost, and it is
easy for large area coating, so it is widely used in many fields. The mirror is heated by ITO that is coated on the surface
of the mirror, the voltage on the ITO will be tuned by changing the output pulse width, and then the system achieves a
closed-loop control. The difference between the mirror temperature and ambient temperature will be maintained in an
ideal range, and this will not only ensure that the mirror surface will not get frosting, but to minimize the impact of
mirror seeing to guarantee the image quality of the telescope. The experimental results show that the temperature control
system can control the different temperature between the mirror surface and the ambient less than 2 degree in real time,
which can improve the mirror's working environment, and the overall effectiveness of the telescope's observations.
Viewing angle changeable display
Show abstract
Viewing angle changeable display can change the display viewing angle as needed: In the public place the display could
have a narrow viewing angle for privacy, while in the private place the displays could have a wide viewing angle for the
convenience of the operation and better viewing experience.
This article propose a novel adjustable optical transmission device to realize the viewing angle changes for LCD by
using the principle of guest- host effect of liquid crystal. The major technology is to insert a special equipment between
the backlight and the LCD, through which the backlight will display either parallel or scattered features to get an either
narrow or wide viewing angle. The equipment is an adjustable transmission cell (ATC) which is actually a black G-H LC
cell. This ATC is the main focus of our invention. The ATC consists of a polarizer sheet and a special guest-host liquid
crystal device filled with the two-phase dye (called as GH-LC in this report), to achieve the viewing angle change in the
LCD. When an electrical field charges to the ATC, only the so-called near-axis lights can pass through the ATC within a
relatively small angle, while the other scattered lights are absorbed sequentially by GH-LC and the polarizer sheet. On
the other hand, when there is no electrical charge to the ATC, the cell behaves like a normal polarizer; and the scattered
light can pass through the cell and polarizer in a normal way. This paper describes the principle and structure of the
device, applies the electric field on the sample to observe the electro-optical properties, combine the theoretical and
experimental research, getting the viewing angle effects of the display.
Principle and design of small-sized and high-definition x-ray machine
Anqing Zhao
Show abstract
The paper discusses the circuit design and working principles of VMOS PWM type 75KV10mA high frequency X-ray
machine. The system mainly consists of silicon controlled rectifier, VMOS tube PWM type high-frequency and highvoltage
inverter circuit, filament inverter circuit, high-voltage rectifier filter circuit and as X-ray tube. The working
process can be carried out under the control of a single-chip microcomputer. Due to the small size and high resolution in
imaging, the X-ray machine is mostly adopted for emergent medical diagnosis and specific circumstances where
nondestructive tests are conducted.
The impact model of cumulative damage on the detection threshold of space optical communication
Show abstract
In order to improve the radiation hardness of free-space optical communication system, this paper theoretically deduces
the radiation damage model of laser diodes' output power. For this model, the theory of Gaussian distribution is used to
study the radiation influence on detection threshold of free-space optical communication on the condition that the bit
error rate keeps invariable. The result shows that both the output power and detection threshold are the linear functions
of total dose.
Dynamic MTF analysis and calculation of aerial camera
Jingyu Liao,
Xiaodong Gao
Show abstract
Mechanical vibration is the main source limiting and damaging the resolution of aerial cameras. It is necessary to
stabilize the line of sight (LOS) to guarantee the image quality. Using dynamic MTF to evaluate image quality and
establish reasonable stabilization system performance standard, is a common artifice during the design process. Linear
motion and high frequency vibration MTF have been expressed in closed form; however, low frequency vibration still
cannot be solved analytically. A numerical dynamic MTF calculation method was developed. With this method and
corresponding results, the image quality as well as affordable residual vibration under particular oscillations can be
predicted. As a result, passive isolators and other image system devices can be selected effectively and properly.
Investigation of DBR used in HB-LED
Show abstract
The high brightness InGaAlP light emitting diodes(LED) is a novel solid-state lighting in recent years. As the absorption
of the red light by the GaAs substrates decreased external quantum efficiency, the development and application of LED
are limited. If all the light incident to the substrate can be reflected, the influences of substrate absorption are radically
improved. Therefore, a novel distributed Bragg reflector(DBR) is proposed. The defect layer whose crystal lattice
constant matched with the substrate grows among the DBR to change the reflectivity spetrum by regulating the defect
layer meterial and thickness. According to matrices-optic theoretics, analogically compute the reflectivity and
transmission spectrum of Al0.5Ga0.5As/AlAs DBR in which has defect layer, corresponding to the wavelength is 610nm
and period is 15. The experimental results show that the reflectivity is not less than 0.6 as the incident angle is greater
than 45°. Hence, a novel method is obtained for enhancing the LED external quantum efficiency.
Time information extraction of return signal for laser altimeter over ladder terrain
Show abstract
Laser altimetry is a new measurement technique. Altimeter receives the return signals after launching laser pulses to the
ground. Three-dimensional information on the ground is obtained by analyzing the corresponding relationship between
return signal features and topographical features. But there is an apparent deficiency when using the data points to
establish the three-dimensional DSM. That is the accurate time information of the return signal cannot be obtained when
positioning the edge lines of the ladder terrain. In this article, the distribution of the echo waveform over the ladder
terrain of city buildings is simulated by a self-designed altimeter waveform simulator under different direction angles
and parameters of the terrain. The best extraction method of the return time information at the edge line is identified by
analyzing the waveform characteristics at the edge line of this terrain, which enhances the accuracy of applications of the
ladder terrain modeling. The time information of the return signal is extracted under various parameters by applying five
methods which are accepted internationally, namely Peak point, Mean point, 50% Rise time point, Center of Area point,
and Midpoint. Then the experiment values are compared to the actual values. According to the results of the simulations,
the difference between the experiment value of the 50% Rise time point and the actual value is minimal. Its resolution
ratio is about ten time units maintaining in a narrow range. It proves that this method can effectively improve the
accuracy of the extracted time information of the return signal at the edge line over ladder terrain. And it provides a valid
data source for establishing a more accurate DSM model.
Identification of the active photo-excited carrier in reverse biased quantum dot resonant tunneling diode
Wangping Wang,
Wenxin Wang,
Hong Chen,
et al.
Show abstract
The active photo-excited carrier has been identified in reverse biased quantum dot resonant tunneling diode (QDRTD)
for light detection. The QD is embedded on the AlAs/GaAs/AlAs double barrier part of the material structure and is
found with strong charge memory effect. The QD is charged with electrons in forward bias and the charge storage of QD
is maintained well in reverse bias until the voltage of QD resonant tunneling peak. With this charge memory effect, the
photo-excited holes are charged into QDs in forward bias and still influence the reverse bias behavior of QDRTD at dark.
Compared to the illuminated QDRTD in reverse bias, the active photo-excited carrier of reverse biased QDRTD is
unambiguously identified as photo-excited holes. The potential profile of QDRTD structure is also calculated and the
potential near charged QDs is found greatly pushed up above GaAs EC. This may explain the trapping of photo-excited
hole by QD for QDRTD in reverse bias.
Research on phase detection on two-dimensional position sensitive detector
Show abstract
Position sensitive detector (PSD) is based on the lateral photoelectric effect (LPE) to produce an electrical. The
photocurrents output from the electrodes, so the amplitude and phase of the output signal are related to the distance
between the light spot and the electrodes. The information of the phase was detached from photocurrent signal. The
diversification of phase along with the distance was analyzed, and phase difference between the corresponding electrode
signal current as well as the associated difference with the change of PSD related parameters. The result of experiment
on one-dimensional and two-dimensional PSD is shown that the position detection error and the linearity all can meet the
test requirements.
A real-time HCI system based on infrared tracking
Show abstract
In this paper, a novel Human-Computer Interaction (HCI) system based on IR tracking technology is proposed for big
projection screen real-time HCI applications. The proposed system has been successfully applied in a multiple-user
shooting game. In this system, each user holds an interactive device, which is based on an ADSP-BF533 hardware
platform, to interact with the shooting game on the big projection screen. IR tracking technology is introduced and
theories for projective transformation are studied in detail. A fast IR marker identification algorithm is developed for
real-time interaction. Two groups of IR markers are adopted in the proposed system for IR tracking, which are fixed on
the border of the big projection screen. To utilize the theories for projective transformation, each group of IR marker is
composed of 4 IR LEDs with a rectangular arrangement. There is a CMOS sensor inside each interactive device to
capture the image of IR markers. The captured image is then used for image processing and IR marker identification on
the ADSP-BF533 hardware platform. According to the theories for projective transformation, the target position on the
big projection screen of each interactive device can be obtained after the projective transformation from the CMOS
image to the big projection screen. An experimental environment is set up and experiments are implemented to test the
validation of the performance of the IR marker identification algorithm, i.e. tracking accuracy, time consuming and
effective region of the proposed system. Experimental results show that the proposed system is very efficient and robust
for big projection screen interaction application. The IR markers can be correctly identified with the identification
algorithm developed in this paper. Experimental results also show that the developed system can achieve real-time
processing and work with high tracking accuracy. The proposed system works well in a large effective region that allows
multiple-user interaction. Moreover, the proposed system can be extended to bigger projection screen interaction
applications with the adoption of more groups of IR marker.
Theoretical study on the cross sensitivity of fiber Bragg grating sensor affected by multi-external fields
Show abstract
The applications of Fiber Bragg grating (FBG) sensors have been concerned considerably for many years. However, it is
usually difficult to obtain an accurate result by single FBG in practical applications, since the phenomenon of cross
sensitivity caused by the multi-external fields always exists. In the past, most of researchers presented their studies only
on the cross sensitivity of two parameters including temperature and axial strain, temperature and transverse pressure,
and so on. Actually, FBG sensors might be affected by temperature field, axial strain field and transverse pressure field
simultaneously in some applications, but no previous analysis has been presented on the cross sensitivity caused by these
three parameters. This work extends the previous works on the cross sensitivity of two parameters to that of three
parameters in a FBG sensor. The sensing model of FBG in three external fields is deduced and analyzed theoretically
from the perspective of its physical mechanism, through which the expression of the cross sensitivity function is
obtained. Meanwhile, examples of different external physical factors and fiber parameters are considered for illustration
purposes, and the cross sensitivity term is discussed by the numerical simulation. The simulated results show that the
properties of cross sensitivity would change in a certain regulation with the changes of external effects and fiber
parameters. Compared to the two-parameter analyzing method, this work makes a more comprehensive analysis to the
research object. Some valuable suggestions about how to reduce the systematic error and improve the measurement
accuracy are put forward as well.
Laser pumping magnetic resonance of theory research based on coherent population trapping
Show abstract
In the Λ three-level system, we will make use of semi-classical density matrix method to analyze cesium (Cs) hyperfine
structure of coherent population trapping (CPT) phenomenon. Coherent population trapping has been widely used in
electromagnetically induced transparency, non-inversion laser, optical storage and ultra-slow speed of light fields, then
strong-coupling light and weak detecting light form coherent laser light to change the hyperfine structure energy levels of
particles number distribution, which impacts on laser pumping magnetic resonance. In this paper, we will discuss the
theoretical analysis and system design of laser pumping cesium magnetometer, cesium atomic energy level formed
hyperfine structure with the I-J coupling, the hyperfine structure has been further split into Zeeman sublevels for the
effects of magnetic field. To use laser pump and RF magnetic field make electrons transition in the Zeeman sublevels to
produce the results of magneto-optical double resonance and on this basis we analyze the influence of laser pumping
magnetic resonance based on coherent population trapping.
Preparation of negative electron affinity gallium nitride photocathode
Show abstract
Negative electron affinity (NEA) Gallium Nitride (GaN) photocathode is an ideal new kind of UV photocathode. NEA
GaN photocathode is widely used in such fields as high-performance ultraviolet photoelectric detector, electron beam
lithography etc. The preparation of negative electron affinity gallium nitride photocathode relates to the growth
technology, the cleaning method, the activation method and the evaluation of photocathode. The mainstream growth
technology of GaN photocathode such as metal organic chemistry vapor phase deposits technology, molecule beam
epitaxial technology and halide vapor phase epitaxial technology were discussed. The chemical cleaning method and the
heat cleaning method for GaN photocathode were given in detail. After the chemical cleaning, the atom clean surface
was gotten by a 700 °C heat about 20 minutes in the vacuum system. The activation of GaN photocathode can be realized
with only Cs or with Cs/O alternately. Using the activation and evaluation system for NEA photocathode, the
photocurrent curve during Cs activation process for GaN photocathode was gotten. The evaluation of photocathode can
be done by measuring the quantum efficiency. Employing the UV spectral response measurement instrument, the
spectral response and quantum efficiency of NEA GaN photocathode were measured. The measured quantum efficiency
of reflection-mode NEA GaN photocathode reached up to 37% at 230 nm.
Research on effect of Kell coefficient on the quality of aerial photography
Yue Fan,
Wenli Ma
Show abstract
The method of Spatial convolution is applied to analyze the imaging process of the CCD imaging system, which involves
optical imaging process and CCD integral sampling process, and the ratio between GRD and GSD that is called Kell
coefficient is introduced, based on which, analysis of effect of Kell coefficient on the quality of aerial photography is
educed. Imaging process of the target is simulated with different Kell coefficient values by matlab. The method of the
gray difference between the target and the image on CCD which is regarded as the evaluation criteria is proposed to
evaluate the image quality. The simulation results show that when Kell coefficient equals 2.8, the target characteristics
can be distinguished.
Luminescent properties of BaAl2Si2O8:Eu2+, Mn2+ phosphor for white LED
Show abstract
BaAl2Si2O8:xEu2+, yMn2+ was prepared by high-temperature solid state reaction and X-ray powder diffraction analysis
confirmed the formation of it. It was found experimentally that, its emission peaks situated at 420 nm and 570 nm
respectively under excitation of 380 nm irradiation. The emission peaks at 420 nm originate from the transition 5d to 4f
of Eu2+ ions that occupy the Ba2+ sites in the crystal of BaAl2Si2O8, while the 580nm emission is attributed to the energy
transfer from Eu2+ ions to Mn2+ ions. The white light can be obtained by combining the 380 nm chip with the phosphor.
When the concentrations of the Eu2+ ions and Mn2+ ions were 0.05 mol and 0.35 mol respectively, the sample presented
intense white emitting. The near-ultraviolet InGaN-based BaAl2Si2O8:0.05Eu2+, 0.35Mn2+ LED achieves good color
rendering of 85 with the CIE coordinate of (0.3183, 0.3036).
The extraction and identification of target signature based coherent wavelet space frequency domain filtering
Show abstract
The location and identification of targets in grey images could be determined by wavelet space frequency domain
identification filter according to coherent space frequency domain technology. Also the infrared spectrum radiation
distribution about the targets could be got by the same algorithm. By making a comparison between the coherent and
non-coherent wavelet space frequency domain filtering algorithms, we knew the former way could filter most clutter
noises, leaving the primary elements about the targets. Both from target grey images and spectrum radiation, the primary
content involved in the target images could be stressed by the former way. Especially more important is the extraction of
target signatures by use of the coherent wavelet space frequency domain filtering algorithm in the spectrum radiation
domain.
CVD diamond soft x-ray detectors
Lifei Hou,
Guohong Yang,
Shenye Liu
Show abstract
A class of wide band-gap semiconductor offers an attractive alternative to Si and X-ray diode (XRD) detector
technologies for x-ray detection in Inertial Confinement Fusion (ICF) experiments. Because diamond presents high
thermal conductivity, resistance and breakdown field, fast charge collection, low leakage current, wide band-gap, low
dielectric constant, large carrier drift velocity and outstanding radiation hardness. Using chemical vapor deposited
(CVD) technology, 1 mm×1 mm×2 mm, 1 mm×1 mm×3 mm diamond was synthesized. And the detectors were fielded
with metal-semiconductor-metal structure. Characteristics of the detectors have been studied on a pulse laser equipment.
The results indicate that the rise time and FWHM of the detector reach 60 ps and 120 ps respectively.
First-principles calculations for geometrical structures and electronic properties of nN-Mg codoped ZnO
Show abstract
We have investigated the geometrical structures, the electronic properties, and the formation energies of nN-Mg codoped
ZnO in neutral state by adopting the first-principles calculations based on the density function theory (DFT). The
calculated results indicate that N atoms prefer to occupy the substitution O site and Mg substitutes the Zn site of the
nearest site of N, which act as an acceptor. Compared with the formation energies of various configurations in neutral
state, it is found that 4N-Mg complex has the lowest formation energy using NO as dopant resource under Zn-rich
condition, indicating that 4N-Mg codoping can enhance the N dopant solubility under this condition. Meanwhile, the Znrich
condition is better for p-type doping than the O-rich condition. It demonstrates that 4N-Mg complex is in favor of
achieving p-type conduction in ZnO. Simultaneously, analysis of density of states (DOS) of nN-Mg complex find that
the valence band maximum (VBM) has a little raise near the Fermi energy level, indicating that the complexes are the
typical p-type characteristic. However, for 4N-Mg complex, the Fermi level is located near the top of valence band.
Furthermore, from the band structure and PDOS of 4N-Mg complex, it is observed that the complex produces an
additional impurity band at the top of the valence band. Meanwhile, the PDOS value of 4N-Mg complex at the Fermi
level is relatively large. In addition, 4N-Mg complex has much lower ionization energy of 0.167eV than that of other
complexes. Therefore, better quality p-type conductivity is achieved by codoping 4N-Mg in ZnO.
Influence of baffle on improving the thickness uniformity of thin film deposited by magnetron sputtering system
He Yu,
Yadong Jiang,
Tao Wang,
et al.
Show abstract
The way of improving the thickness uniformity of the thin film deposited by magnetron sputtering system is presented in
this paper. A simple model for the magnetron sputtering system with a baffle between cathode target and substrate is
described. Based on this model, it is possible to predict the relative deviation of film thickness with this baffle-model by
taking the shape and size of baffle into the consideration. The purpose of this article is to explain how different baffle
parameters affect the uniformity of thin film using the method of finite element with rectangle target in this magnetron
system. It is found that there may exist optimum baffle conditions where the relative deviation of thin film thickness is
less than 3 % with a diameter of Φ 150 mm substrate.
Analysis of titanium and vanadium oxide thin film by method of reactive co-sputtering
Tao Wang,
Yadong Jiang,
He Yu
Show abstract
A systematic simulation based on Berg's model and theoretic study of co-reactive sputtering of titanium and vanadium
targets is presented. It enables one to predict the hysteresis effect and intermediate composition of the deposited film as a
function of different targets current in the co-reactive sputtering process. With this approach, it is possible to obtain
different stoichiometry of thin film by choosing different ratio of vanadium target current to titanium target current. In
this case, the material composition in the thin film with respect to the fraction of these two targets current can be
optimized. Finally, the deposition rate of co-reactive sputtering as a function of total sputtering rate of two metal material
atoms is also described.
Photoluminescence investigation of InAs quantum dots in quantum well with different strain reducing layer
Show abstract
The emission dynamics properties of InAs self-assembled quantum dots (QDs) embedded in InGaAs/GaAs quantum well
with different strain reducing layer (thin InAlAs and GaAs) were systematically investigated by time-resolved and
temperature dependent photoluminescence (TR and TD PL) measurements. We observe that a thin 10 monolayer (ML)
GaAs layer may increase the emission wavelength, and 1 nm additional InAlAs layer results a significant nonlinear redshift
of above 1.3 μm photoluminescence (PL) peak, which can be explained from the strain analysis. TDPL spectra
display an anomalous enhancement behavior of the integrated PL intensity around 150 K for the InAs QD structures
without the InAlAs layer, which may be described by the reduced carrier transition at higher temperature for the higher
energy barrier of the InAlAs layer. We study systematically PL decay time of the InAs with different structures. The PL
lifetime of quantum dots grown on a 10 ML GaAs layer is a littler longer than those without the layer, and a more
InAlAs layer may result in a greatly increase of PL lifetime, which implies that the InAlAs layer with higher energy
barrier may enhance the quantum restriction of carriers in InAs QDs. The above phenomena also approve the facts that
the main mode of carrier migration is quantum tunneling effects at lower temperature, while it is the quantum transition
at the higher temperature. We explained these measuring results from the competition between the carrier recombination,
escape and redistribution.
Laser active imaging-guided anti-tank missile system small-scale integration design
Mingliang Yan,
Xiangqian Shan,
Zhou Qu
Show abstract
At present, the domestic and international third-generation anti-tank missiles, laser-guided missiles are mostly divided
into active laser-guided and laser semi-active guidance, this guidance system, there are vulnerable to electronic
interference, can not be fully realized after launching deficiencies. Article based on this, an in-depth understanding of
imaging-guided laser-active working principle, based on the pairs of third-generation anti-tank missile guidance system,
boldly proposed to improve the anti-tank missiles, laser-active small-scale integration of imaging guidance system
design, the main purpose is to improve a certain type of The optical target missile, TV angle measurement, laser-guided
instruction transmission means, so that anti-tank missiles to achieve forward-looking, the next obstacle avoidance TV
and multi-functional integration of the entire after launching smart missiles, and in theory be able to study the new antitank
missiles play a certain reference.
Systematical investigations of annealing effects on electrical properties and thermal sensitivity characteristics of TiO2-δ thin films by DC reactive magnetron sputtering
Show abstract
In recent years, TiO2-δ thin films as a kind of thermal sensitive material have been attracting more and more attention on
the application of infrared devices. In this article, TiO2-δ thin films from the technology of DC reactive magnetron
sputtering were deposited on glass substrates under the same sputtering conditions while different annealing conditions.
Annealing effects on electrical properties and thermal sensitivity characteristics were systematically investigated under
different annealing conditions including annealing circumstance, annealing time and annealing temperature. Results
indicated that the sheet resistance (R) and temperature coefficient of resistance (TCR) of TiO2-δ thin films would
decrease after vacuum-annealing and would increase after oxygen-annealing. Furthermore, they would increase more and
more when the annealing time and the oxygen flux increased during oxygen-annealing. On the contrary, R and TCR
would decrease when the annealing temperature went up. Based on that, TiO2-δ thin films could be better applied on
related devices under proper technique of annealing.
A new method of building footprints detection using airborne laser scanning data and multispectral image
Yiping Luo,
Ting Jiang,
Shengli Gao,
et al.
Show abstract
It presents a new approach for detecting building footprints in a combination of registered aerial image with multispectral
bands and airborne laser scanning data synchronously obtained by Leica-Geosystems ALS40 and Applanix DACS-301
on the same platform. A two-step method for building detection was presented consisting of selecting 'building'
candidate points and then classifying candidate points. A digital surface model(DSM) derived from last pulse laser
scanning data was first filtered and the laser points were classified into classes 'ground' and 'building or tree' based on
mathematic morphological filter. Then, 'ground' points were resample into digital elevation model(DEM), and a
Normalized DSM(nDSM) was generated from DEM and DSM. The candidate points were selected from 'building or
tree' points by height value and area threshold in nDSM. The candidate points were further classified into building points
and tree points by using the support vector machines(SVM) classification method. Two classification tests were carried
out using features only from laser scanning data and associated features from two input data sources. The features
included height, height finite difference, RGB bands value, and so on. The RGB value of points was acquired by
matching laser scanning data and image using collinear equation. The features of training points were presented as input
data for SVM classification method, and cross validation was used to select best classification parameters. The
determinant function could be constructed by the classification parameters and the class of candidate points was
determined by determinant function. The result showed that associated features from two input data sources were
superior to features only from laser scanning data. The accuracy of more than 90% was achieved for buildings in first
kind of features.
Up-converion in bismuth doped fibers
Show abstract
We investigated the up-conversion fluorescence characteristics of the bismuth doped silica fibers with and without Al codopant
(BA fiber and BI fiber). Unusual up-conversion fluorescence was discovered in both of these two fibers when
excited by pump lasers. After more experiments, it was found that the BI fiber showed more complicated and distinct upconversion
spectrum than the BA fiber, but with different and weaker NIR emission as we reported before. And it was
implied that the up-conversion fluorescence should be mainly responsible for the Bi2+ ions which was rich in BI fiber.
Thus, by properly improve the Al co-doping concentration could alleviate the fluorescence up-conversion thus improve
the efficiency of the NIR band fluorescence. Besides, the complicated up-conversion fluorescence bands may helpful to
clarify the energy levels of the Bi ions in silica materials.
Design of optimized quantum well infrared photodetector's structure including higher order effects
Jupeng Jin,
Chun Lin
Show abstract
Photoconductive GaAs/AlGaAs quantum well infrared photodetector (QWIP) achieves best performance when the well
has its first excited state resonant with barrier height. Optimum QWIP structure parameters can be designed according to
this rule. The parameters calculated by simple square well model taking account of variable effective mass are not
accurate enough and can merely provide a rough estimation for actual QWIP devices. Higher order effects including
band nonparabolicity, quantum confined Stark-effect and Coulomb interaction of large number of charge carriers (also
known as Many-body effect) can have considerable influence on the energy level of quantum wells. Band
nonparabolicity effect was included in the calculation in this paper. And a group of optimized GaAs/AlGaAs n-type
QWIP structure parameters covering wavelength from 7 μm to 16 μm were systematically calculated, using one band
effective mass approximation (EMA) and shooting method. These calculated results were carefully compared with those
where band nonparabolicity was not considered, and 4 ± 2% discrepancy was found. Since a photoconductive QWIP
normally works under a certain bias, change of the confined state energy level and shift of peak wavelength caused by
the quantum confined Stark-effect were calculated and discussed. All the calculated quantum well structure parameters
in this paper will offer a more accurate guide for QWIP fabrication.
Liquid crystal writable gratings for beam steering
Yali Gao,
Mingwei Li,
Yongji Shi,
et al.
Show abstract
Liquid crystal writable grating technology is being developed for beam steering in laser radar systems. It is ability to
steer broad-spectral -band radiation for us in passive sensors. There is potential for these devices in microscan systems
because there is little or no dispersion for the small scan angles required in microscanning. The dispersion that is less
than the resolution of the sensor considered here. For large angle steering, the dispersion correction or a narrowing of the
spectral bandwidth is required. The degradation in sensitivity resulting from narrowing the spectral bandwidth is
considered. A high quantum efficiently step-stare sensor with a two-dimensional focal plane array responsive over a
narrow spectral width can achieve the same sensitivity as current linear scanning sensors while being able to steer the
field of view(FOV) over a larger field of regard with no moving parts. A promising approach for steering a narrow FOV
with broad spectral content and good resolution is described.
Detection algorithm of infrared small target based on improved SUSAN operator
Xingmiao Liu,
Shicheng Wang
Show abstract
The methods of detecting small moving targets in infrared image sequences that contain moving nuisance objects and
background noise is analyzed in this paper. A novel infrared small target detection algorithm based on improved SUSAN
operator is put forward. The algorithm selects double templates for the infrared small target detection: one size is greater
than the small target point size and another size is equal to the small target point size. First, the algorithm uses the big
template to calculate the USAN of each pixel in the image and detect the small target, the edge of the image and isolated
noise pixels; Then the algorithm uses the another template to calculate the USAN of pixels detected in the first step and
improves the principles of SUSAN algorithm based on the characteristics of the small target so that the algorithm can
only detect small targets and don't sensitive to the edge pixels of the image and isolated noise pixels. So the interference
of the edge of the image and isolate noise points are removed and the candidate target points can be identified; At last,
the target is detected by utilizing the continuity and consistency of target movement. The experimental results indicate
that the improved SUSAN detection algorithm can quickly and effectively detect the infrared small targets.
Analyzing the emission self-organized structure in gas discharge by photoelectric detect method
Show abstract
In gas discharge, various self-organized structures are formed as the applied voltage is increased. A noticeable
phenomenon is that the system undergoes twice hexagon structure. One is observed in the lower voltage range and the
other is in the higher voltage range. To study the intrinsic mechanism, the light signal, electric signal, and the emission
spectrum of the two hexagons is measured by photoelectric detect method. The electric signal is detected by high-voltage
probe. The light signal is measured distinguished in time and space by using diaphragm. The electron excitation
temperature is measured using spectrum method. It is conclude that the forming mechanism of the two kinds of hexagon
is different. The lower-voltage hexagon is a dynamic multiplex structure, while the higher-voltage hexagon is a single
static structure. The excitation temperature of higher-voltage hexagon is higher than that of lower-voltage hexagon.
Multi-feature fusion diagnosis for optoelectronic tracking devices using fuzzy measurement
Show abstract
With the rapid development of optoelectronic tracking and measurement technology, tracking equipments become more
complex and more precise, and the system faults happen at higher probability. The fault orientation, the fault analysis
and the fault exclusion change more difficult. The single information and the simple process of multi-information have
many deficiencies, which need fusion to improve the reliability. The D-S theory of evidence is a way to resolve the
uncertain problems, which fuses evidences to reason the decision results in the same recognition frame used at the
decisional level. Using the D-S theory of evidence, a diagnosis frame of multi-feature information fusion is proposed.
The deviation ranks of the fault characters is defined according to their offsets from the normal and their happening
probabilities were also computed by using the statistical results and the existing knowledge. The data reasoning of rough
set theory is employed to construct the key fault evidence space from the multi features. Further, Gaussian subjection
function from the fuzzy theory is used to describe the distribution of the key evidences and the distribution of the test
data, and the basic probabilities of the evidence are weighed by the matching degree of the two distributions. The multiperiod
and space feature information are employed and fused, and the final diagnosis decision is made by some effective
methods. A multi-feature information fusion diagnosis for the servo system of the tracking equipment is discussed. The
test shows that the diagnosis reliability is improved and the diagnosis uncertainty is reduced, and the fault diagnosis for
the precise device and other parts are also effectively resolved by using this fusion method.
Effect of temperature on the growth of vanadium oxide films deposited by DC reactive magnetron sputtering
Show abstract
Vanadium oxide films were prepared onto glass and KBr substrates at various deposition temperatures by DC reactive
magnetron sputtering. X-Ray photoelectron spectroscopy (XPS), Atomic force microscope (AFM), Fourier transform
infrared spectroscopy (FT-IR) were employed to analyze the VOx films, respectively. Experimental results indicated that
deposition temperature has a great impact on the surface morphology of vanadium oxide films. The XPS analysis
confirmed that the vanadium oxide films prepared are V2O5. From Fourier transform infrared spectroscopy, it can be see
that the infrared active mode corresponding to V-O-V stretching vibration and the stretching vibration of unshared V=O
bonds appeared at about 840 cm-1 and 915 cm-1 in the films formed at 240 , respectively. A shift in the peak position
towards higher frequency was found with increasing the deposition temperature which indicated that the films formed at
higher deposition temperature were structural disorder.
Measurement and analysis of modulation transfer function of the third generation low-light-level image intensifier
Show abstract
The modulation transfer function (MTF) is measured at different illuminance in order to guarantee the veracity of
measuring MTF of the third generation low-light-level image intensifier, the measuring result is analyzed. It is concluded
that the law of MTF and illumiance, which is valuable for measuring MTF of the third generation low-light-level image
intensifier and similar device.
Investigation of fabricating the films in the phase transition regime from amorphous to microcrystalline by MWECR CVD system
Show abstract
The microcrystalline silicon films in the phase transition regime from amorphous to microcrystalline were fabricated by
microwave electron-cyclotron-resonance chemical vapor deposition (MWECR CVD) system. The influence of
deposition temperature and deposition pressure on the structure and electrical properties of microcrystalline silicon films
was investigated. It is shown that the films in the phase transition regime from amorphous to microcrystalline are easier
to fabricate under the condition of lower deposition pressure and higher substrate temperature. For example, the films in
the phase transition regime whose crystalline volume fraction is about 30 %, were deposited at substrate temperature of
170 °C and deposition pressure of 0.7 Pa. The films' μτ product is about the order of magnitude of 10-5, whose
magnitude is two order higher than that of amorphous silicon films, and their photosensitivity is about 103~104.
Therefore, having both high stability and excellent optoelectric properties of the high-quality and device grade film, it is
suitable to fabricate the intrinsic materials for amorphous silicon based solar cells.
Inspection focus technology of space tridimensional mapping camera based on astigmatic method
Zhi Wang,
Liping Zhang
Show abstract
The CCD plane of the space tridimensional mapping camera will be deviated from the focal plane(including the CCD
plane deviated due to camera focal length changed), under the condition of space environment and vibration, impact
when satellite is launching, image resolution ratio will be descended because defocusing. For tridimensional mapping
camera, principal point position and focal length variation of the camera affect positioning accuracy of ground target,
conventional solution is under the condition of vacuum and focusing range, calibrate the position of CCD plane with
code of photoelectric encoder, when the camera defocusing in orbit, the magnitude and direction of defocusing amount
are obtained by photoelectric encoder, then the focusing mechanism driven by step motor to compensate defocusing
amount of the CCD plane. For tridimensional mapping camera, under the condition of space environment and vibration,
impact when satellite is launching, if the camera focal length changes, above focusing method has been meaningless.
Thus, the measuring and focusing method was put forward based on astigmation, a quadrant detector was adopted to
measure the astigmation caused by the deviation of the CCD plane, refer to calibrated relation between the CCD plane
poison and the asrigmation, the deviation vector of the CCD plane can be obtained. This method includes all factors
caused deviation of the CCD plane, experimental results show that the focusing resolution of mapping camera focusing
mechanism based on astigmatic method can reach 0.25 μm.
Detection of weak and small infrered targets under complicated background
Jinling Chen,
Jiming Zhang,
Linming Deng,
et al.
Show abstract
The technique of weak small target detection and recognition has been the key technique of the electro-optical detecting
system, many scholars are engaging the research of detection for weak and small targets. The effective detection for
small targets in low SNR images is still a hot research field. Because infrared sensor is easily affected by atmosphere hot
radiation, long distance and sensor noise, the detected targets in infrared images often present like small targets and
drowned in noise. The basic problem inherent to extent the detection range is the detection of small, low observable, no
obvious structural information in images and complicated background. In order to improve the detection ratio of weak
small targets and decrease the false alarming ratio in the condition of complicated background, the paper presents the
technology of pretreatment of infrared images and the technology of detection for weak small targets, mainly including
the technology of Sobel edge algorithm and multi-degree and multi-orientation gradient.
Based upon horizon-correlative characteristic of infrared images which were gotten by scanning, considering of the
target properties in complicated background, an algorithm of weak and small target detection is presented. Because the
images appear horizon-correlative characteristic, Sobel horizontal operator is adopted. By this algorithm, the background
clutter was suppressed. Then an adaptive threshold was proposed to extract the precise location of small target.
Incorporated with the two methods, a single frame weak and small target detection algorithm was built. Its high
performance was then proved in a serial of experiments.
In order to solve the detection problems of weak and small infrared targets under complicated background, a detection
algorithm integrating with multi-degree and multi-orientation gradient fusion is proposed. Based on the principle of
infrared radiation property of target, i.e., the gradient variations of pixel gray scale in horizontal and vertical directions,
the algorithm handles the property of weak and small target into analysis of image singularity and detects targets by
means of multi-degree gradient step length. Then the detected results show this method can remove most false targets. As
a result, the algorithms have fulfilled the engineering demands for reliability and real-time property.
Influences of process parameters of low frequency PECVD technology on intrinsic stress of silicon nitride thin film
Show abstract
Silicon nitride (SiNx) thin films were deposited by low frequency (LF) plasma enhanced chemical vapor deposition
(PECVD) technology. By systematic variation of the process parameters, e.g. reactive gas flow rate, LF power, chamber
gas pressure and substrate temperature. Influences of above parameters on the intrinsic stress of SiNx films were studied and analyzed by combining with the measured refractive index (RI), density, infrared spectra results of deposited SiNx
films. The results showed that intrinsic stress of SiNx film was roughly proportional to film density, which was inversely
proportional to hydrogen content in the SiNx film. Substrate temperature during deposition was the most important factor
affecting hydrogen content in deposited film and, accordingly, the density and intrinsic stress of SiNx film.
Optical fiber sensor for nitroaromatic explosives based on fluorescence quenching
Fenghong Chu
Show abstract
The detection of explosives and related compounds is important in both forensic and environmental applications. In this
paper, we report on the preparation of novel plastic optical fiber explosive sensor based on fluorescence quenching. A
low priced LED light source and PIN detector were used in this sensor system, a U-shaped plastic optical fiber with high
sensitivity act as sensor head. We use amplifying fluorescent polymers (AFP) MEH-PPV as fluorescence indictor. MEHPPV
was dip coated on to the surface of the U-shaped plastic optical fiber. For the first time as far as we know we
detected the fluorescence lifetime by the phase-fluorometry method to measure the concentration of TNT, which has a
merit of immunity to fluctuation of the light source and is more reliable than measuring intensity alone. In the
experimental set-up the phase shift between excitation light and fluorescence is calculated by correlation method. Two
degree phase difference was measured when the sensor head was exposed to TNT vapor and air in primary experiments.
Calculation of intrinsic surface acoustic wave velocity in LiNbO3
Tao Liu,
Kuanxin Yu
Show abstract
Lithium Niobate (LN) crystal has excellent piezoelectric properties, it can be used as substrates of surface acoustic wave
(SAW) devices, for example delay line, filter, oscillator, convolver and so on. Intrinsic SAW velocity is determined by
the internal property of crystals. In this paper, SAW acoustic basic equation group and SAW mechanical boundary
condition equation group are deduced. Intrinsic SAW velocities are calculated systematically using a circle iterative
method in zx, xy and yz three coordinate planes of LN along different directions. Stiffness coefficient of piezoelectric
crystal can be changed by piezoelectric effect and it is named as piezoelectric modified stiffness coefficient. Reciprocal
velocity Curves of LN in the three coordinate planes using the non-modified stiffness coefficients and the modified
stiffness coefficients are drawn. Many characters of the SAW device are related to the acoustic velocities, so research
results lay a solid base for design and manufacture of the SAW device. It has theoretical significance and practical value.
Optimum cut direction of lithium niobate as substrate in surface acoustic wave devices
Show abstract
A cut direction, rotated ZY cut of Lithium Niobate (LN), is studied. LN is a good piezoelectric crystal and it can be used
as substrate of surface acoustic wave devices. In this paper, surface acoustic wave equations, including basic equations
and boundary condition equations, are deduced. According to these equations the surface acoustic wave velocities are
systematically calculated using a circle iterative method for LN along different directions in optimum decoupling
acoustic sagittal YZ plane. The electromechanical coupling coefficients for rotated ZY cut LN are also calculated. The
optimum cut direction of the LN crystal piece as substrate of surface acoustic wave devices is determined by the largest
electromechanical coupling coefficient.
Study on the cloud layer height and properties in Hefei observed by lidar
Show abstract
A co-axial transmission elastic-backscattered lidar aiming to detect the optical properties of the clouds is presented in
this paper. The modular co-axial design can guarantee the consistency of the transmitting part and the receiving part. In
practice a specific diaphragm is used to suppress the stray light of the primary mirror and background light to improve
SNR of the backscattered signal in the daytime. So the near ground signal must be corrected with the appropriate overlap
factor. A Licel transient recorder is used for data acquisition in analog and photon counting combined in one acquisition
system. With the 15 MHz sampling rate, the spatial resolution of 10 m can be attained. The control over the transient
recorder and the treatment of the data is performed on a PC. After getting the correctional backscattered signal, retrieving
and analyzing the extinction coefficient profile, the cloud base, cloud peak and related optical parameters of the clouds
can be confirmed. In order to testify the feasibility of our lidar, it was implemented with a Finland ceilometer Vaisala
simultaneously in May in 2008 in Hefei. Results show the lidar system is stable and the data is reliable.
Analysis of properties of ZnCoO bulks by solid state reaction
Xueqiong Su,
Li Wang,
Jiangbo Chen,
et al.
Show abstract
Zn0.9Co0.1O bulks were prepared by solid state reaction at various fritting temperatures in order to investigate the
structural and optical properties of the bulks. The valence electron and doping concentration in bulk was measured by Xray
photoelectron spectroscopy (XPS) instrument. Some basic properties of the bulk material in powder were examined
to enhance the comprehension of magnetism in these semiconductors. The corresponding magnetic properties were
evaluated by field-cooling and zero-field-cooling magnetization measurements, while the optical properties were tested
by Fourier transformed infrared spectrum (FTIR). It is indcated that Co ions are well inserted in the ZnO structure and
surrounded by four oxygen. It means that a series of Co have substituted Zn and the sample all the same maintains
original wurtzite structure in lattice with a sintered temperature of 1200 °C, then it leads to chemical bond formation of
Co-O. Furthermore, the fritting temperature do not play a crucial role in the determination of Co content.
Method of improving the accuracy of image motion measurement for panoramic aerial cameras
Gang Li,
Ping Jia
Show abstract
To improve the accuracy of image motion measurement for panoramic aerial cameras, the paper proposed a method of
real-time image motion measurement based on 2D spatial correlation. An auxiliary area CCD is positioned paralleled to
the main linear TDI CCD in the focal plane of the camera. For every frame of the image sequence taken by the auxiliary
CCD, a prediction on the displacement of the current image in the flight direction is made based on the forward image
motion velocity. The current and the reference images are combined together for 2D-correlation, which products an
image motion vector. By decomposing the vector, both the forward and pendulum-swing image motions can be
determined. The demanding computational requirements for the real-time 2D-correlation are covered by a joint transform
optical correlator. Simulation test results show that the accuracy is improved and the measurement error is within 0.2
pixels for input images with SNR=1 dB.
Research on anti-blooming driving timing for CCD video camera
Site Mo,
Qi Liu
Show abstract
How CCD camera causes vertical blooming was investigated. The technique based on vertical driving timing, which can
clear vertical blooming up the high-intensity pixels, was presented. The saturated charge of photo diode, which is
produced by high-intensity-pixel during the exposure time of a line, enters the vertical shift register. On the control of
CCD vertical driving timing, all pixels of the same column add the saturation charge, and then the image has vertical
blooming. The vertical blooming up the high-intensity-pixel is produced by the saturation charge of the last frame.
Depended on the control method of charge transfer, a special driving timing, which can transfer the remaining charge, is
used for clearing the vertical blooming up the high-intensity-pixel. The driving timing is tested on a CCD demo board of
ICX205, and the testing showed that the vertical blooming up the high-intensity-pixel is deleted. This method has been
applied to intelligent traffic monitoring.
Adaptive optimization agorithm for CDS control parameters of high-speed CCD
Site Mo,
Qi Liu
Show abstract
The signal-to-noise ratio of the charge coupled devices (CCD) output can be improved by the optimization of control
parameters of correlated double sampling (CDS), however, the control parameters of CDS of high-speed CCD is difficult
to determine from experiments. In this paper, an adaptive algorithm is proposed to adjust the control parameters of CDS.
With fixed target and exposure parameters, the CDS control parameters such as the width of reset pulse, the timing of
noise sampling and data sampling are tuned. The images on all combination of the CDS control parameters are acquired.
The square sum of the Tenengrad function of all pixels on each image is used to evaluate the quality of the image. The
combination of the three CDS parameters corresponding to the maximum sum is chosen as the CDS control parameters,
and then the signal-to-noise ratio of the CCD out is the best. Finally, the algorithm is implemented in FPGA and the
experiments results show that, compared with the best image acquired without adaptive algorithm, the parameters of
edge profile improved from 507.4 to 763.8, the parameters of MTF50 improved from 526.5 to 937.8.
Quadruple region extended displaying using mirror image
Show abstract
A liquid crystal display (LCD) recently comes into common use. It is possible for this display unit to provide the
same size of displaying area as the image screen on the panel. Thus the conventional display can show only one
screen, but it is impossible to enlarge the size of a screen, for example twice. To enlarge the display area, the
authors have developed an enlarging method of display area using a mirror. Our extension method enables the
observers to show the virtual image plane and to enlarge a screen area twice. In the developed display unit, we
made use of an image separating technique using polarized glasses, a parallax barrier or a lenticular lens screen for
3D imaging. The mirror can generate the virtual image plane and it enlarges a screen area only twice. In this
paper, we present a new extension method to enlarge a screen area quadruple.
Glasses-free 3D display system using special grating film with view control effect
Show abstract
We developed a glasses-free 3D stereoscopic display using an LCD display panel and a special grating film for
stereoscopic viewing. The display screen is divided in half in order that left and right regions provide the
stereoscopic images for left and right eyes. Because both stereoscopic images are not in the same position, it is
difficult for the observer to view the 3D image by the stereoviewing. The grating film can solve this problem
because it shifts both left and right images to the same position. Moreover this grating film can give us glassesfree
3D viewing because of its view control effect. As the result, the observer can watch overlapped stereoscopic
images for left and right eyes without special glasses such as polarized glasses.
4-views tabletop flat display system for collaborative work on round table
Show abstract
The authors have researched support system of the reminiscence and life review activity. This support system
consists of an interactive tabletop display and interface system. On the reminiscence and life review activity, a
therapist puts pictures on the table so as to trigger a talk. However some observers may perceive upside down
images if they sit down opposite the therapist. To overcome this problem, we have developed the display system
which can be viewed from any direction. In this paper, we propose a 4-views tabletop flat display system for
cooperative activity on a round table.
Light-weight monocular display unit for 3D display using polypyrrole film actuator
Show abstract
The human vision system has visual functions for viewing 3D images with a correct depth. These functions are
called accommodation, vergence and binocular stereopsis. Most 3D display system utilizes binocular stereopsis.
The authors have developed a monocular 3D vision system with accommodation mechanism, which is useful
function for perceiving depth. This vision unit needs an image shift optics for generating monocular parallax
images. But conventional image shift mechanism is heavy because of its linear actuator system. To improve
this problem, we developed a light-weight 3D vision unit for presenting monocular stereoscopic images using a
polypyrrole linear actuator.
Optical characteristics of 9, 10-diphenylanthracene nanocrystals fabricated by reprecipitation
Show abstract
9,10-Diphenylanthracene (DPA) nanocrystals were prepared using a reprecipitation method. Morphologies and Optical
properties of DPA nanocrystals were investigated by a scanning electron microscope (SEM), UV-Visible absorption and
fluorescence emission spectra, respectively. The results showed that a large amount of DPA nanocrystals form and have
a width of about 300-500 nm, a length of 500 nm, a thickness of a few tens of nanometers. Optical properties of the
nanocrystals are obviously different from those of DPA monomer. All absorption peaks for DPA nanocrystals experience
a bathochromic shift with respect to those of DPA monomer due to the formation of J-aggregates in the nanocrystals.
The emission peaks of DPA nanocrystals are red-shifted compared with those of the diluted solution, which are
attributed to the intermolecular force difference between the monomer and nanocrystals. In addition, the mechanisms of
nanocrystals formation were also analyzed and discussed in detail.
Stereo matching based on SIFT descriptor with illumination and camera invariance
Haitao Niu,
Xunjie Zhao,
Chengjin Li,
et al.
Show abstract
Stereo matching is the process of finding corresponding points in two or more images. The description of interest points
is a critical aspect of point correspondence which is vital in stereo matching. SIFT descriptor has been proven to be better
on the distinctiveness and robustness than other local descriptors. However, SIFT descriptor does not involve color
information of feature point which provides powerfully distinguishable feature in matching tasks. Furthermore, in a real
scene, image color are affected by various geometric and radiometric factors,such as gamma correction and exposure.
These situations are very common in stereo images. For this reason, the color recorded by a camera is not a reliable cue,
and the color consistency assumption is no longer valid between stereo images in real scenes. Hence the performance of
other SIFT-based stereo matching algorithms can be severely degraded under the radiometric variations. In this paper,
we present a new improved SIFT stereo matching algorithms that is invariant to various radiometric variations between
left and right images. Unlike other improved SIFT stereo matching algorithms, we explicitly employ the color formation
model with the parameters of lighting geometry, illuminant color and camera gamma in SIFT descriptor. Firstly, we
transform the input color images to log-chromaticity color space, thus a linear relationship can be established. Then, we
use a log-polar histogram to build three color invariance components for SIFT descriptor. So that our improved SIFT
descriptor is invariant to lighting geometry, illuminant color and camera gamma changes between left and right images.
Then we can match feature points between two images and use SIFT descriptor Euclidean distance as a geometric
measure in our data sets to make it further accurate and robust. Experimental results show that our method is superior to
other SIFT-based algorithms including conventional stereo matching algorithms under various radiometric changes.
Studies on the lateral emission of erbium-doped fiber amplifiers
Debao Zhang,
Setsuhisa Tanabe
Show abstract
The spectral power distribution of side emission from erbium-doped fibers lateral was measured by an integrating sphere
and was evaluated quantitatively. The power of side upconversion is very low and the evidence of the contribution of
signal laser to the upconversion is observed. The side spontaneous emission power was much larger than ASE power
and nearly saturated at the lower pump power. With increasing Er3+ ions concentration, the contribution of signal laser
to the green upconversion decreases and the side spontaneous emission are almost same under the strong 100mW
pumping. According to the side emission and scattering power and the end output power, the energy budget is
tabulated.
Recursive SAM-based band selection for hyperspectral anomaly detection
Yuanlei He,
Daizhi Liu,
Shihua Yi
Show abstract
Band selection has been widely used in hyperspectral image processing for dimension reduction. In this paper, a
recursive SAM-based band selection (RSAM-BBS) method is proposed. Once two initial bands are given, RSAM-BBS
is performed in a sequential manner, and at each step the band that can best describe the spectral separation of two
hyperspectral signatures is added to the bands already selected until the spectral angle reaches its maximum. In order to
demonstrate the utility of the proposed band selection method, an anomaly detection algorithm is developed, which first
extracts the anomalous target spectrum from the original image using automatic target detection and classification
algorithm (ATDCA), followed by maximum spectral screening (MSS) to estimate the background average spectrum,
then implements RSAM-BBS to select bands that participate in the subsequent adaptive cosine estimator (ACE) target
detection. As shown in the experimental result on the AVIRIS dataset, less than five bands selected by the RSAM-BBS
can achieve comparable detection performance using the full bands.
Threat assessment of aerial target in ultra-wide field of view infrared image
Yulong Zhou,
Mingqiang Xing,
Yongzhong Wang
Show abstract
When the target is several miles away from the ultra-wide field of view (UWFV) infrared warning system, it will be a
point target in the infrared image, so there is no the target information of distance, geometry and texture without which it
is hard to assess the threat of target accurately. It is very important for the air defense command and decision making to
have a correct threat assessment of the aerial target, and at present there are few reports about the aerial target threat
assessment of the UWFV infrared warning system. The characteristic of the UWFV infrared image is analyzed. A laser
range finder is used to measure the initial distance of each target which will be sent back to the infrared warning system.
Together with the target information of initial distance, gray value, course angle and angular altitude, considering the
nonlinear characteristic of aerial target threat assessment, the threat assessment method based on RBF neural network is
presented for its good self-adaptive and self study ability to solve nonlinear complex problems. After simulation
experiment, it is found that this method is available and effective.
The research of Organophosphorus pesticide biosensor characteristic
Show abstract
To study the fiber-sensor film applied in detecting Organophosphorus pesticide, methyltriethoxysilane was used as
precursor, which was doped by FITC- AchE. Consequently, the excellent Acetylcholinesterase biology sensitivity film
was prepared. Physics characteristic of the film and sensitivity of Organophosphorus pesticide were researched. In
organophosphorus pesticide residue testing, the experimental results indicated that the linear measurement range could
reach 10-7~10-6 mol/L, moreover the detection limit is 10-8 mol/L. The sensor could be applied in biological / chemical
research, clinical medicine, environmental protection, food inspection, biochemical preventive war field and so on.
Bad pixel replacement based on spatial statistics for IR sensor
Show abstract
IR focal plane arrays typically contain bad pixels. Bad pixels have to be corrected because those can significantly impair
the performance of target-detection algorithms. On the other hand, particularly as an aid to visual interpretation, it is
desirable to replace the bad pixels. IR image contains spatial information and is correlative in spatial domain. In spatial
statistics the semivariogram is an important function that relates semivariance to sampling lag. This function can
characterize the spatial dependence of each point on its neighbor and provide a concise and unbiased description of the
scale and pattern of spatial variability. One of the main reasons for deriving semivariogram is to use it in the process of
estimation. Kriging is an interpolation and estimation technique that considers both the distance and the degree of
variation between known data points when estimating values in unknown areas. In this paper a new technique based on
spatial statistics is developed for bad pixel replacement. The main objective of the technique is to replace bad pixels
through Kriging estimation. Theory analysis and experiments show that the method is reasonable and efficient.
Scanning capacitance microscopy characterization on diffused p-n junctions of InGaAs/InP infrared detectors
Hao Yin,
Yongfu Li,
Wenjuan Wang,
et al.
Show abstract
The p-n junctions in planar detectors are usually formed by diffusion of p-type impurity, and the effect
of diffusion is crucial for device performance. This work reports the investigation of cross-sectional
scanning capacitance microscopy (SCM) on the p-type diffusion in device structures of planar
InGaAs/InP infrared detectors. Compare to other methods, SCM can provide 2-dimensional carrier
distribution mapping with nanometer resolution, thus it meets the requirement of the measurement on
micrometer sized photosensitive elements. This work covers two types of InGaAs/InP device structures:
i.e. the avalanche photodiodes (APD) and the PIN near-infrared detectors. For APD structures, we
obtain the 2-dimensional carrier distribution and vertical p-type depth under 3 diffusion conditions. For
PIN near-infrared detectors, the SCM image provides the diffused p-n junction both on the vertical and
lateral direction. A stronger lateral diffusion around the InGaAs/InP heterojunction is observed, which
indicates the influence of InGaAs/InP boundary on the vertical diffusion. And the junction region can
be detected distinctly from the SCM profile, exhibiting the nanometer scale resolution. Finally, the ratio
of lateral to vertical Zn diffusion distance in InP is acquired as 0.67. Our results demonstrate the
distinctive capability of SCM investigation on semiconductor optoelectronic device structures.
Measuring of spectral BRDF using fiber optic spectrometer
Wei Zhang,
Fugang Wang
Show abstract
We designed a new spectral bidirectional reflection distribution function (BRDF) measurement instrument, which can be
utilized to measure isotropic materials simply in laboratory. The measurement instrument consists of a fiber optic
spectrometer, a three-dimensional turntable, a halogen light source and a computer. The spectrometer acquires 696
samples in visible band. The angular range controlled by three-dimensional turntable is 0~330° and 0~80° for azimuth
angle and zenith angle respectively. The halogen light source supplies a continuous spectrum with high efficiency and
stability in the wavelength range from 360~1500 nm. The spectrometer and the three-dimensional turntable connect with
the computer. The angle rotation and data acquisition are all controlled by the computer. The spectral BRDF
measurement of three materials is conducted. The relation of spectral BRDF, wavelength and reflected zenith angle is
presented. In conclusion, the designed spectral BRDF measurement system can acquire spectral BRDF data quickly and
accurately, thus it is an efficient way to measure material spectral reflected properties which is need for computer
rendering, target identification.
The study on organic solar cells based on bathocuproine as an exciton blocking layer
Show abstract
Using a buffer layer between C60 and cathode was an important and popular approach to improve the performance of
organic photovoltaic cells. In this work, we chose CuPc (Copper(II) phthalocyanine) as an electron donor material, C60
(fullerene) as an electron acceptor material and BCP (Bathocuproine) as an exciton blocking layer to fabricate an organic
solar cells with a structure of ITO/CuPc/C60/BCP/Ag, and studied the relationship between the photoelectric properties of
organic solar cells and the film thickness of BCP. The results showed that the power conversion efficiency (PCE) was
closely related to the thickness of exciton blocking layer. With the increasing of BCP film thickness, the power
conversion efficiency of the device increased first and then decreased. When the thickness was 0 nm, the power
conversion efficiency (PCE) was 0.357 %. When the film thickness was 25 nm, the PCE was 1.013 %. And when the
thickness was 50 nm, the PCE was 0.43 %. However, when the thickness was 100 nm, the PCE was 0 %.We presumed
that the exciton blocking layer reduce the quenching rate at the interface between organic layer and cathode so that
exciton can be separated into electrons and holes more effectively. As a result, the PCE increased. At the same time, if
the film of BCP layer thickness is too thick, PCE would sharply decrease due to high resistance during collecting charge
carriers.
The growth of cubic boron nitride films on the interlayer of nickel by RF sputter
Show abstract
In this paper, the buffer interlayer was formed by first depositing a pure nickel layer on the p-type Si (100) substrate,
and then the boron nitride thin films were deposited by using radio frequency magnetron sputter. We used the purity of 99.99 % nickel and purity of 99.99 % boron nitride (h-BN) as targets in the experiment. Step profiler has been employed to measure the thickness of nickel interlayer and cubic boron nitride thin films. Fourier transformed infrared spectroscopy (FTIR) has been employed to characterize boron nitride thin films. The content of cubic phase boron nitride in the films has been calculated through the FTIR spectra. The surface morphology and the grain size of films were examined using an atomic force microscope (AFM). The mixture gas of argon and nitrogen was as the working
gas in our experiment. To study the thickness of nickel interlayer how to influence the formation of cubic phase in the boron nitride thin film, we changed the thickness of nickel interlayer by controlling the sputtering time with the same substrate temperature, working gas pressure and other conditions. The results showed that the thickness of nickel
interlayer is the key factor in the formation of cubic boron nitride. The growth of cubic boron nitride at room temperature can be realized by appropriately selecting the thickness of nickel interlayer. We also drew out when the
thickness of nickel interlayer was about 150nm, the content of cubic phase in boron nitride thin films would get up to the highest. On this basis of these results, we also examined impacts of the substrate temperature (100~400 °C), substrate bias (50~210 V) and annealing conditions on the formation of the cubic boron nitride thin films.
Detection performance of laser range-gated imaging system
Show abstract
Laser radar is rapidly developing towards very capable sensors for number of applications such as military sensing and
guidance, auto collision avoidance, robotic vision and atmospheric sensing. In this paper, the detection performance of
non-scanned Laser Rang-gated (LRG) imaging system is studied. In order to compute the detection range of laser active
imaging system, the range equation is derived by using laser illuminating model and considering factors which affect
system imaging quality. According to the principle of laser radar and the characters of objects and the detectors in special
applied setting, it mainly deduced the non-scanned laser radar range equation of the range-gated system, meanwhile, the
SNR model of non-scanned LRG imaging system is set up. Then, relationship of the detection probability, the false
alarm probability and the signal-to-noise ratio in the non-scanned LRG imaging system are analyzed, the influence
factors of system's performance are pointed out, and the solution is proposed. The detection performance simulation
software of non-scanned LRG imaging system is designed with MATLAB and the performance of the imaging system is
simulated.
In-situ self-assembled polyaniline/carbon nanotubes nanofiber thin films for ammonia gas sensors
Huiling Tai,
Yadong Jiang,
Guangzhong Xie
Show abstract
Polyaniline/carbon nanotubes (PANI/CNTs) nanocomposite thin films were fabricated through an in-situ self-assembled
method on the interdigitated electrodes for ammonia (NH3) gas sensors. CNTs presented in this work consisted of singlewalled
CNTs (SWNT) and multi-walled CNTs (MWNT). The pure MWNT dispersed in N,N-Dimethyl Formamide
(DMF) solution was also dipped on the interdigitated electrodes for gas-sensing property comparison. The SEM images
showed clearly that PANI/CNTs nanocomposite thin films possess a nanofiber mesh like structure, and TEM analysis
exhibited that the diameter of the pure MWNT was 10 nm whereas that of the PANI/MWNT nanofiber was about 50 nm,
which confirmed a PANI layer packed on the surface of MWNT during the in-situ polymerization process. The gasresponse
of different sensing films to NH3 was investigated at room temperature. It was found that PANI/MWNT
nanocomposite thin film exhibited the higher sensitivity than pure MWNT film and PANI/SWNT thin film, which might
be ascribed to more active sites for gas adsorption for the PANI/MWNT nanocomposite thin film. The response-recovery
property was studied when the PANI/MWNT thin film sensor was exposed to different concentrations of NH3 ranging
from 23 to 141 ppm, and it was found that the sensitivity was linear to the concentrations of NH3. This sensor also had
good reproducibility and selectivity.
9.3 X continuous zoom optical system with finite conjugate distance
Yiyu Li,
Yuanyuan Wang,
Dexi Zhu,
et al.
Show abstract
A continuous zoom optical system with finite conjugate distance was designed for low-vision aid device. The
configuration of the zoom optical system and the evaluation of the optical performance including modulation transfer
function(MTF) and diffuse spot in diameter were investigated. The stability of the system performance was forecast by
using the tolerance sensitivity analysis and Monte Carlo method. This mechanically compensated zoom lens combines
four group components including a fixed objective, moving variator and compensator, and a fixed eyepiece with a total
of 10 pieces of lens. The optical system which has a tube length of 76 mm and a front intercept distance of 262 mm can
realize continuous zoom from 8.8~ 52 mm and 9.3 X zoom ratio without any image vignetting or obvious fluctuation in
image quality.
Optical tracking method based on geometric feature point of the extended target
Show abstract
Optical tracking systems need to measure the shift of target in real time so as to compensate the shift effect. For extended
target, template matching techniques are usually used to estimate the image shift, in which the shift can be computed up
to subpixel with the parabolic interpolation. In this paper, we propose a new method to estimate the shift accurately
building on geometric feature point tracking. The method first extracts feature points from the reference image using
Harris detector, and tracks the same feature point by correlating the small patch around it with that of each point detected
in other images. The subpixel feature point position utilized to estimate the image shift is then determined by the
modified Harris strength of the pixels around that point. Experimental results validates that the proposed method can
accurately measure image shifts over large distance under noisy conditions, and that the mean of estimate error is less
than 0.03 pixels. Moreover, the contrast of long exposure images before and after shift compensation is compared to
evaluate our algorithm in the optical tracking system.
Adaptive NUC algorithm for uncooled IRFPA based on neural networks
Ziji Liu,
Yadong Jiang,
Jian Lv,
et al.
Show abstract
With developments in uncooled infrared plane array (UFPA) technology, many new advanced uncooled infrared sensors
are used in defensive weapons, scientific research, industry and commercial applications. A major difference in imaging
techniques between infrared IRFPA imaging system and a visible CCD camera is that, IRFPA need nonuniformity
correction and dead pixel compensation, we usually called it infrared image pre-processing. Two-point or multi-point
correction algorithms based on calibration commonly used may correct the non-uniformity of IRFPAs, but they are
limited by pixel linearity and instability. Therefore, adaptive non-uniformity correction techniques are developed. Two of
these adaptive non-uniformity correction algorithms are mostly discussed, one is based on temporal high-pass filter, and
another is based on neural network. In this paper, a new NUC algorithm based on improved neural networks is
introduced, and involves the compare result between improved neural networks and other adaptive correction techniques.
A lot of different will discussed in different angle, like correction effects, calculation efficiency, hardware
implementation and so on. According to the result and discussion, it could be concluding that the adaptive algorithm
offers improved performance compared to traditional calibration mode techniques. This new algorithm not only provides
better sensitivity, but also increases the system dynamic range. As the sensor application expended, it will be very useful
in future infrared imaging systems.
Research of image enhancement of dental cast based on wavelet transformation
Jing Zhao,
Zhongke Li
Show abstract
This paper describes a 3D laser scanner for dental cast that realize non-contact deepness measuring. The scanner and the
control PC make up of a 3D scan system, accomplish the real time digital of dental cast. Owing to the complexity shape
of the dental cast and the random nature of scanned points, the detected feature curves are generally not smooth or not
accurate enough for subsequent application. The purpose of this p is to present an algorithm for enhancing the useful
points and eliminating the noises. So an image enhancement algorithm based on wavelet transform and fuzzy set theory
is presented. Firstly, the multi-scale wavelet transform is adopted to decompose the input image, which extracts the
characteristic of multi-scale of the image. Secondly, wavelet threshold is used for image de-noising, and then the
traditional fuzzy set theory is improved and applied to enhance the low frequency wavelet coefficients and the high
frequency wavelet coefficients of different directions of each scale. Finally, the inverse wavelet transform is applied to
synthesis image. A group of experimental results demonstrate that the proposed algorithm is effective for the dental cast
image de-noising and enhancement, the edge of the enhanced image is distinct which is good for the subsequent image
processing.
Luminescent properties of Tb(acac)2AA nanorods prepared by ultrasound irradiation
Le Zhou,
Hongquan Yu,
Haijun Guo
Show abstract
Rare earth organic complexes possess characteristic luminescent properties, such as extremely sharp emission bands,
long lifetime and potential high internal quantum efficiency. The corresponding nano-materials have attracted extensive
attention recently owing to the potential application for OLED and photovoltaic devices. In this report, ternary complex
of rare earth Tb(acac)2AA (acac= acetyl acetone, AA= acrylic acid ) uniform nanorods have been prepared by
sonication. The properties of Tb(acac)2AA nanorods were characterized by X-ray diffraction (XRD), Fourier transform
Infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). It is interesting to observe that the
nanoparticles with diameter of 300 nm are growing into the nanorods with size of 80×1200 nm (W×L) with the
increasing of the power output. It can be explained that the cavitation effect was increased with the increasing power
output and thus accelerated the growth of nanorods from nanometer-sized seed on the Tb(acac)2AA nanoparticles.
Furthermore, the size of the nanorods is much smaller than that of the bulk prepared by precipitation. The luminescent
properties of Tb(acac)2AA nanorods were studied in comparison with that of the bulk. The results indicated that the line
shapes of corresponding luminescent spectras are similar, but the luminescent intensity of the nanorods is two times
stronger than that of the bulk. It means that the nanorods have higher fluorescence quantum efficiency than the bulk. In
addition, the fluorescence lifetime of the nanorods is obviously longer. In summary, sonication is an effective approach
to prepare rare earth nanomaterial with high luminescence efficiency.
Three-dimensional location of tomato based on binocular stereo vision for tomato harvesting robot
Show abstract
Accurate harvesting depends on the order of the accuracy of 3D location for harvesting robot. The precision of location
is lower when the distance between fruit and camera is larger than 0.8 m for the method based on binocular stereo vision.
This is a big problem. In order to improve the precision of depth measurement for ripe tomato, two stereo matching
methods were analyzed comparatively which were centroid-based matching and area-based matching. Their
performances in depth measurement were also compared. Experiments showed that the relationship between distance and
measurement was linear. Then, models of unitary linear regression (ULR) were used to improve the results of depth
measurement. After correction by these models, the depth errors were in a range of -28 mm to 25 mm for centroid-based
matching method and -8 mm to 15 mm for area-based matching method at a distance of 0.6 m to 1.15 m. It can be
concluded that costs of computation can be decreased with the promise of good precision when the parallax of centroid
which is acquired through centroid-based matching method is used to set the range of parallax for area-based matching
method.
Development of the tongue coating analyzer based on concave grating monochrometer and virtual instrument
Show abstract
The tongue coating diagnosis is an important part in tongue diagnosis of traditional Chinese medicine (TCM).The change
of the thickness and color of the tongue coating can reflect the pathological state for the patient. By observing the tongue
coating, a Chinese doctor can determine the nature or severity of disease. Because some limitations existed in the tongue
diagnosis method of TCM and the method based on the digital image processing, a novel tongue coating analyzer(TCA)
based on the concave grating monochrometer and virtual instrument is developed in this paper. This analyzer consists of
the light source system, check cavity, optical fiber probe, concave grating monochrometer, spectrum detector system
based on CCD and data acquisition (DAQ) card, signal processing circuit system, computer and data analysis software
based on LabVIEW, etc. Experimental results show that the novel TCA's spectral range can reach 300-1000 nm, its
wavelength resolution can reach 1nm, and this TCA uses the back-split-light technology and multi-channel parallel
analysis. Compared with the TCA based on the image processing technology, this TCA has many advantages, such as,
compact volume, simpler algorithm, faster processing speed, higher accuracy, cheaper cost and real-time handle data and
display the result, etc. Therefore, it has the greatly potential values in the fields of the tongue coating diagnosis for TCM.
Infrared activity of crystalline silicon and amorphous silicon
Show abstract
The thermo-resistance effect in silicon has been exploited for the fabrication of uncooled infrared detectors. In this paper,
based on the Schrodinger equation of material radiation system and the micro-structure of silicon, the infrared absorption
theory of silicon is analyzed. The results show that the infrared activity of amorphous silicon is more activate than
crystalline silicon because of the fault and long range disorder, and using the impurity B, Li, and H, the infrared activity
of silicon also will be activated.
Si (211) substrate thinning technology for HgCdTe focal plane arrays on Si substrates
Shan Zhang,
Chenfei Wang,
Juying Cao,
et al.
Show abstract
A wet chemical etching method for (211)Si substrates was demonstrated in this paper. The morphologies and cleanness
of (211) Si surface etched in different mixture ratio HF-HNO3-HAC solutions have been studied by using optical
microscope and the surface profile measuring system (SPMS). The analysis of the surface images indicated that the Si
etched by the HF-HNO3-HAC (2:15:5) has the smoother surface, and the wet chemical etching can effectively eliminate
the damage introduced by the chemo-mechanical polishing. An auto wet chemical etching agitator which can move in
the vertical orientation was used. The wet chemical etching rate of (211) Si was obtained in the room temperature and the
transmitted spectra of (211) Si with different thickness were measured by Fourier Transform Infrared Spectroscopy
(FTIR) and compared. It is confirmed that the Si with different thickness make no difference to the spectral response in
mid-wave. By using this novel technology, the Si substrate of HgCdTe/Si detector was removed completely with the HF-HNO3-
HAC (2:15:5) solution. It is obvious that the wet chemical etching method can remove the (211) Si substrates with
no damage and detector can work better.
Research on testing field flaws of image intensifier based on spatio-temporal SNR
Bin Zhou,
Bingqi Liu,
Dongsheng Wu
Show abstract
Image intensifier is the kernel of low-light-level device. The field flaw is one of the important index parameters of the
image intensifier. Traditionally the statistic number of the image intensifier's field flaws is calculated through the
people's eyes by the aid of an optical microscope, which main limitation is subjective and inefficient. With the broad
application of the high-powered CCD and digital imaging processing method in testing performance of image intensifier,
the method of appraising SNR based on spatio-temporal noise theory can accurately reflect the spatio-temporal
heterogeneous of fluorescence's output image and fulfill the requirements of digital and automatic test. The limitation of
the flaws' shape and position can be disregard and the accurate flaws' inspection can be realized rapidly by this method.
In this paper, the main factors of forming the field flaws are analyzed and the mathematic model of spatio-temporal SNR
is deduced. The hardware devices of the test system for image intensifier's spatio-temporal SNR are discussed. The
spatio-temporal SNR of Gen image intensifier is tested by this test system and the test software based on Visual C++
and Matlab. The digital and automatic test of a factitious field flaw is realized by the theory of spatio-temporal SNR. The
test precision can achieve pixel level. The experimental results show that this new method is rational, reliable and
visualized.
Multi-object spectral imaging based on MEMS
Show abstract
The primary compact high resolution imaging spectrometer was developed and reported. Due to
its numerous wave bands the original image data is always in a huge scale and costs a tremendous
process overhead, but the data amount of the region of interest is as a rule in the order of thousandth, if
not less, of that of the whole push-broom region. With a digital micromirror device (DMD), only the
region of interesting object is imaged by the imaging spectrometer, which results in a distinct reduction
of data quantity and a high data compression ratio.
A DMD of high turning rate and residential time adjustability is used as a spatial light modulator
to fulfill the object selection function. It is placed after the fore objective and able to reflect the object
to either the panchromatic CCD camera channel or the imaging spectrometer channel. The position of
the object can be firstly determined through the image interpretation from panchromatic imaging
channel and a DMD control command is executed to switch the corresponding mirrors to the imaging
spectrometer channel, thus only the object region of interest is imaged by the spectrometer.
The multiple objects of both printed patterns and real leaves are accurately determined and
selected according to their different locality and shape features. The panchromatic and hyperspectral
image data are both collected for further effective object recognition.
A white organic light-emitting diode based on anthracene-triphenylamine derivatives
Show abstract
White organic lighting-diode (WOLED) can be used as flat light sources, backlights for liquid crystal displays and full
color displays. Recently, a research mainstream of white OLED is to develop the novel materials and optimize the
structure of devices. In this work a WOLED with a structure of ITO/NPB/PAA/Alq3: x% rubrene/Alq3/Mg: Ag, was
fabricated. The device has two light-emitting layers. NPB is used as a hole transport layer, PAA as a blue emitting layer,
Alq3: rubrene host-guest system as a yellow emitting layer, and Alq3 close to the cathode as an electron transport layer. In
the experiment, the doping concentration of rubrene was optimized. WOLED 1 with 4% rubrene achieved a maximum
luminous efficiency of 1.80 lm/W, a maximum luminance of 3926 cd/m2 and CIE coordinates of (0.374, 0.341)
.WOLED 2 with 2% rubrene achieved a maximum luminous efficiency of 0.65 lm/W, a maximum luminance of
7495cd/m2 and CIE coordinates of (0.365,0.365).
A novel spectrum measurement system
Qiang Qi,
Quan Jiang
Show abstract
A novel spectrum measuring system, which was based on the embedded system of ARM, controlled by a PC was
developed. The system is composed of a monochromator, a high-precision voltage amplifier, an ARM7 system and a PC.
The monochromator convert optical signal into electronic signal, and the signal is then amplified by the voltage
amplifier. Then the amplified signal is converted to digital signal by the ARM7 system. At the end, the digital is send to
the PC by the USB interface. After the processing and analyzing of the data, PC can measure and display the spectrum of
the light source real-time. The system can measure the spectrum and chromaticity coordinates of light source and display
device with high precision, and has a friendly interface.
Method for laser disturbing image quality evaluation based on wavelet weight and correlation
Show abstract
The advantages and disadvantages of conventional image quality evaluation methods are analyzed and according to the
characteristics of laser disturbing image, an image quality evaluation method which is based on wavelet weight and
correlation is established. In the method, both the original and disturbed images are processed by wavelet decomposition,
replacement and reconstruction. Then different sub-band images are obtained and their correlations are calculated.
Combined with band-pass characteristic of human vision, visual weighted coefficients are obtained and objective
calculation results are output finally. Experimental results show that this method not only can overcome the influences of
different conditions on evaluation of laser disturbing effect, but it is also in good agreement with the subjective method.
Structure design and performance analysis of the CsI(Tl) thin film crystal cell
Show abstract
In this paper, we design a structure of CsI(Tl) thin film crystal cell, and cover the CsI(Tl) thin film on the surface of the
CCD directly. In order to prevent the photons emit from the surface of film, which result in depressing the fluorescence
efficient, we cover the film with alumina to form reflective layer. Al layer is used to separate the CsI(Tl) crystal
according to the size of CCD photosensitive cell, which solve problem that fluorescence cross talk between the different
photosensitive cell. The fluorescence transmission efficiency of CsI(Tl) film crystal cell model is also researched , the
results show the fluorescence transmission efficiency is maximum when the thickness of film is 40 μm.
The analysis of the interference hyperspectral image features and compression
Lei Zhang,
ShanCong Zhang,
Xiangli Bin,
et al.
Show abstract
Interference hyper spectral image and the images contain some interference information which are collected by the
LASIS are only middle results of the spectrometer, is a three-dimensional image. The amount of the data is large size,
and need to be compressed. For testing the actual interference hyper spectral image, use different composed way, to
compose of LAMIS and LADIS image, the LASIS image has different target with different spectral band, LAMIS has
the same target with different spectrum, LADIS has the same spectrum with different target . The spatial correlation and
spectral correlation are analyzed. The self-coefficient and cross-coefficient are also calculated. The method that LASIS
extract into LADIS is proposed, which separate interference information form spatial image, and it is a new foundation
for interference information protection of LASIS image. The feather of LASIS image is revealed, the results obtained can
be use LASIS image processing and compressing.
The manufacture of a binary optic liquid crystal blazed grating and its electro-optical properties
Kun Liu,
Ziqiang Huang,
Jimin Wang,
et al.
Show abstract
A photoresist film was applied on the indium tin oxide (ITO) conductive glass which was coated with silver. The
photoinduced changes of the photoresist film were achieved by exposure to UV lamp through a grating & lead pattern
photomask. The photoresist film exhibited grating lines and lead patterns after development. The Ag-ITO double film
coated with photoresist patterns was etched to double-layer electrode patterns by ion beam. After photoresists were
stripped, silver grating electrodes were removed and ITO grating electrodes were coated with polyimide (PI) and treated
by rubbing. The orientation was perpendicular to grating. The back electrode was a piece of ITO glass which was
oriented by the same method. Nematic liquid crystal (LC) was injected into the grating cell. Other silver-leads were
retained and connected with driver ICs and flex circuits. The binary optic liquid crystal blazed grating was fabricated.
Step-shaped phase was obtained by applying a step-shaped voltage on LC grating electrodes. It formed blazed grating at
one order and the diffraction angle can be shifted dynamically. The sample was checked up by the optical microscope
and the He-Ne laser. The results indicate that the sample had clear grating structure and every grating electrode can be
controlled separately. The range of the first order of diffraction angle was ±6° in theory. The diffraction efficiency
decreased as the diffraction angle increased, and the maximum diffraction efficiency can exceed 80 %.
Acidic chemical bath deposition of Cd1-xZnxS thin films
Meng Cao,
Yan Sun,
Jie Wu,
et al.
Show abstract
Cd1-xZnxS ternary material has a wider band gap than CdS which makes it a better window material for use in CdTe solar
cells. Typical chemical bath deposition (CBD) processes for sulfides employ an alkaline medium containing the
chalcogenide source and the metal ion. In this work, Cd1-xZnxS thin films have been deposited from acidic solution. The
composition, surface morphology and structural properties of the as-deposited and annealed Cd1-xZnxS thin films were
studied using energy dispersive X-ray analysis (EDX), scanning electron microscopy (SEM) and X-ray diffraction
(XRD) techniques. The band gap of the as-deposited Cd1-xZnxS thin films varied from 2.38 to 2.44 eV, whereas in the
annealed films varied from 2.36 to 2.42 eV. The decreased band gaps of the Cd1-xZnxS thin films were due to the
improved crystalline nature of the material.
Custom aspherical ophthalmic lens design
Show abstract
The Liou's model eye is close to anatomical, biometric and optical realities, and is effective in predicting the optical
performance. An efficient approach for designing of ophthalmic lenses by regarding ophthalmic lens and Liou's model
eye as a single optical system, based on optimization of aspherical surface coefficients is presented. The wavefront
aberration and diopter are taken into consideration, the traditional damped least-squares methods are chosen with the
high order aspherical equations being used. The appearance of the lens designed is improved obviously than the spherical
ones and the fabricating is not complicated; the optical performances are controlled in an acceptable range. With the help
of the structure parameters of a single eye ball obtained, custom-design ophthalmic lens is workable which might be a
direction of lens design in the future.
Fabrication and characterization of photo cathode materials for transparent organic light-emitting diodes
Hui Lin,
Junsheng Yu,
Nana Wang,
et al.
Show abstract
In this work structural composition and fabrication process of cathode for transparent OLED were investigated. Using a
LiF/Al/Ag/Alq3 semitransparent cathode and a Mg:Ag/ITO cathode, green fluorescent transparent organic light-emitting
devices (TOLEDs) were fabricated. ITO was evaporated as a cathode onto a thin Mg:Ag layer by DC magnetron
sputtering method with the assistance of tiny H2O vapor during deposition process. The fabrication of LiF/Al/Ag/Alq3
electrode was processed without breaking the vacuum. At a bias of 15 V, the luminance of the TOLED with Mg:Ag/ITO
and LiF/Al/Ag/Alq3 cathode were 3016 and 4535 cd/m2, respectively. The results indicate that LiF/Al/Ag/Alq3 electrode
can be used as an effective and stable cathode in TOLEDs.
Full parallax 3D stereoscopic display
Show abstract
The conventional display can show only one screen, but it is impossible to enlarge the size of a screen, for
example twice. A mirror makes another world in the silver coated glass. The authors have ever presented an
enlarging method of display area using a mirror. Our extension method enables the observers to show the virtual
image plane and to enlarge a screen area twice. To provide twice enlarged region, the surface of a visual display
needs to produce dual views. Although the displaying region is doubled, this virtual display could not produce
3D images. To solve this problem, we must prepare to generate four views; side by side observing view
windows enable us to perceive stereoscopic 3D images and a vertical neighbor viewing window makes dual views
for enlarging display area. In this paper, we propose a 3D imaging display with horizontal and vertical parallaxes
using an angle-controlled unidirectional 4-views display.
Research on vision control system for inverted pendulum
Xiaolin Jin,
Yongming Bian,
Jia Jiang,
et al.
Show abstract
This paper focuses on the study and experiment of vision control system for an inverted pendulum. To solve some key
technical problems, the hardware platform and the software flow of the control system have been designed. The whole
control system is composed of vision module and motion control module. The vision module is based on "CCD camera",
the motion control module is based on "Motion Control Card, Servo Driver and Servo Motor", and the software is based
on LabView. The main research contents and contributions of this paper are summarized as follows: (1) Analyze the
functional requirements of the vision control system about the inverted pendulum, developing the hardware platform and
planning the overall arrangement of the system; (2) Design the image processing flow and the recognition track process
of the moving objects. The accurate position of the pendulum can be obtained from the image through the flow, which
concludes image pretreatment, image segmentation and image post-processing; (3) Design the software structure of the
control system and write the program code. It is convenient to update and maintain the control software due to the
modularity of the system. Some key technical problems in the software have been solved, so the flexibility and reliability
of the control system are improved; (4) Build the experimental platform and set the key parameters of the vision control
system through experiments. It is proved that the chosen scheme of this paper is feasible. The experiment provides the
basis for the development and application of the whole control system.
Novel reflectivity-difference biosensor
Han Chen,
Lian Wei,
Ying Feng
Show abstract
The traditional immobilized biomolecule detection technique on arrays has been fluorescence, but this has limitations
because of its reliance on fluorophores. Alternatively, many label-free detection techniques have been developed such as
surface plasmon resonance (SPR), ellipsometry, thin-film interference, diffractometry, and waveguides. These techniques
have the advantage of high speed and high sensitivity, but in exchange rely on complicated structures or detailed sensing
cells. A novel reflectivity-difference biosensor is introduced in this paper. When the sensor covered with a protein layer,
the cells and the land would have opposite changes of the reflectance which lead to intensity shifts at the far-field
diffraction plane. Therefore, it is convenient for the operation without intricate sensor structures and multifarious optical
systems.
Poling and characterization of a novel organic/polymer electro-optic material
Show abstract
Electro-optic organic/polymer material is important for the fabrication of polymer integrated optic-electronic devices and
organic sensors. Recently, a novel organic high μβ value chromophore FFC have been synthesized by molecular design.
The absorption spectrum in 400-4000 cm-1 is measured for the material, and the measurement result shows that the
absorption loss is negligibly small. An organic/polymer high electro-optic activity material FFC/PSU is obtained by
dissolving guest FFC (wt. 20%) and a host polysulfone (PSU) in a solvent. The resolvability of cyclohexanone for the
material is satisfactory by comparison with other solvents experimentally, and the preparation of FFC/PSU thin film is
ease relatively. The materiel is poled by electric field-assisted contact poling, and the near optimum poling condition is
determined by adjusting poling parameters as pre-curing duration, poling temperature and poling voltage etc. The
electro-optic coefficient of the material is measured as high as 130pm/V by using the widely accepted simple reflection
technique. The investigation indicates that the FFC/PSU has excellent characteristics, such as high electro-optic
coefficient, low absorption loss, good thermal stability and capability for withstanding the subsequent process
techniques, suitable for the fabrication of high-performance integrated optic-electronic devices and sensors.
Self-assembly of conducting polymer nanowires as hole injection layer for organic light-emitting diodes applications
Yajie Yang,
Yadong Jiang,
Jianhua Xu,
et al.
Show abstract
We reported a controlled architecture growth of high density and ordered nanowire film of poly(3,4-ethylene
dioxythiophene) (PEDOT) via Langmuir-Blodgett (LB) technique, and self-assembly performance of PEDOT nanowires
at air/water interface was investigated in detail. The conducting film consisting of high density and ordered nanowires
was transferred onto ITO substrate as a hole injection layer for organic light emitting diodes (OLEDs). The results
showed that, compared to conventional PEDOT film, the improved performance of OLEDs was obtained after using
ordered PEDOT nanowire layer as hole injection layer. It also indicated that compact arrangement and well-ordered
structure of conducting channel was attributed to the improvement of OLED performance, leading to the increase of
charged carrier mobility in hole injection layer and the recombination rate of electrons and holes in the
electroluminescent layer.
Study on the dependence of properties of TiOx heat sensitive films on deposit oxygen flow rate
Show abstract
In this article, titanium oxide thin films (TiOx) are prepared with the reactive DC sputtering in an oxygen and argon
atmosphere. Properties of titanium oxide films could be largely varied by controlling the deposition condition. Here we
study on the dependence of sheet resistance, thickness, optical transmittance and film composition of titanium oxide
films on different deposit oxygen flow rates.
White light LED based on YAG:Ce3+ and YAG:Ce3+,Gd3+ phosphor
Show abstract
YAG:Ce3+ and a yellow-orange phosphor YAG:Ce3+,Gd3+ were prepared by solid-state reaction. Excitation spectrum of
YAG:Ce3+ was composed of two bands peaking at 335nm and 460nm. Emission band of YAG:Ce3+ peaking at 532nm
corresponds to the 5d-->4f transition of Ce3+.The emission peak wavelength of YAG:Ce3+,Gd3+ shifted to longer
wavelength with the increasing of the concentration of Gd3+. White LED was obtained by combining GaN(460nm) chip
with different ratios of phosphor YAG:Ce3+ and YAG:Ce3+,Gd3+.As the ratio of YAG:Ce3+,Gd3+ phosphor increased, the
color rendering index of the LED improved significantly under the forward bias of 20mA. White LED with color
rendering index of 85, CIE chromaticity coordinates of (0.3040, 0.2911), and color temperature Tc of 7615K was
obtained as the ratio of YAG:Ce3+ and YAG:Ce3+,Gd3+ was 5:3.
White organic light-emitting diodes based on doped and ultrathin Rubrene layer
Yi Li,
Yadong Jiang,
Wen Wen,
et al.
Show abstract
Based on a yellow fluorescent dye of 5, 6, 11, 12-tetraphenylnaphthacene (Rubrene), WOLEDs were fabricated, with
doping structure and ultrathin layer structure utilized in the devices. By doping Rubrene into blue-emitting N,N'-bis-(1-
naphthyl)-N,N'-biphenyl-1,1'-biphenyl-4,4'-diamine (NPB), the device with a structure of indium-tin-oxide (ITO)/NPB
(40 nm)/NPB:Rubrene (0.25 wt%, 7 nm)/2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) (30 nm)/Mg:Ag
exhibited a warm white light with Commissions Internationale De L'Eclairage (CIE) coordinates of (0.38, 0.41) at 12 V.
The electroluminescent spectrum of the OLED consisted of blue and yellow fluorescent emissions, the intensity of blue
emission increased gradually relative to the orange emission with increasing voltage. This is mainly due to the
recombination zone shifted towards the anode side as the transmission rate of electrons grows faster than that of holes
under higher bias voltage. A maximum luminance of 7300 cd/m2 and a maximum power efficiency of 0.57 lm/W were
achieved. Comparatively, by utilizing ultrathin dopant layer, the device with a structure of ITO/NPB (40 nm)/Rubrene
(0.3 nm)/NPB (7 nm)/BCP (30 nm)/Mg:Ag achieved a low turn-on voltage of 3 V and a more stable white light. The
peaks of EL spectra located at 430 and 560 nm corresponding to the CIE coordinates of (0.32, 0.32) under bias voltage
ranging from 5 to 15 V. A maximum luminance of 5630 cd/m2 and a maximum power efficiency of 0.6 lm/W were
achieved. The balanced spectra were attributed to the stable confining of charge carriers and exciton by the thin emitting
layers. Hence, with simple device structure and fabricating process, the device with ultrathin layer achieved low turn-on
voltage, stable white light emitting and higher power efficiency.
Study on lifetime of high brightness green organic light-emitting devices
Show abstract
To analyze why the device degrade, we have processed the pictures, which we got when the device degraded, with
Matlab programs. The areas of dark spots in the pictures were calculated quantitatively. And we also got the effective
light-emitting area and the proportion of dark spots. Comparing and contrasting the attenuation curve of the lightemitting
area and the luminance, we could study further the reasons why the device degraded and know how to improve
the operation lifetime of device. In this study, a kind of high brightness green organic light-emitting diode was selected
as the research object, with a typical OLED multilayer structure, ITO/CuPc/α-NPD/Alq3:C545T/Alq3/LiF/Al. The device
started working required only 2.5 V, with a emitting peak at 525 nm and maximum luminous efficiency 3.92 lm•W-1.The
brightness of the device was measured to be 2500 cd•m-2 at the drive voltage 20 V. To restrain the permeation of vapor
and oxygen into the device, it was encapsulated in low vacuum and high purity of nitrogen. It was a effective way to
protect the device and ensure all kinds of device properties steady. Nevertheless, it's inevitable that vapor and oxygen
permeated into the device due to the porosity of epoxy resin. The results showed that vapor and oxygen both would result
in the light-emitting area decrease. On the one hand, vapor would peel away the cathode from the organic layer and bring
in some bubbles; on the other hand oxygen would cause oxidation of cathode and organic layer. As a result, the dark
spots appeared, grew up, and finally attached together forming a non-emitting area.
Different materials as a cathode modification layer on the impact of organic solar cells
Show abstract
Organic thin film solar cells based on conjugated polymer or small molecules have showed an interesting approach to
energy conversion since Tang reported a single donor-accepter hetero-junction solar cell. The power conversion
efficiency of organic solar cells has increased steadily over last decade. Small-molecular weight organic double
heterojunction donor-acceptor layer organic solar cells (OSC) with a structure of indium-tin-oxide
(ITO)/CuPc(200Å)/C60(400Å)/x/Ag(1000Å), using CuPc(copper Phthalocyanine)as donor layer, and Alq3(8-Hydroxyquinoline
aluminum salt), BCP(Bromocresol purple sodium salt) and Bphen(4'7-diphyenyl-1,10-phenanthroline) as
cathode modification layer, respectively were fabricated. The performance of OSC was studied as a function of the
different materials as an cathode modification layer to optimize the structure. The current-voltage characteristic of the
solar cell under AM1.5 solar illumination at an intensity of 100 mw/cm2 showed that the power conversion efficiency
(PCE) was dependent of the different materials of the cathode modification layer. the efficiency along with the different
materials as an cathode modification layer will diminish under that standard solar illumination(AM1.5)was obtained.
Using a double heterostructure of ITO/CuPc(200Å)/C60(400Å)/Alq3(60Å)/Ag(1000Å) with high-vacuum evaporation
technology, the efficiency was 0.587%.the efficiency was 0.967% when the material of the cathode modification layer
was BCP, with the structure of ITO/CuPc(200Å)/C60(400Å)/BCP(35Å)/Ag(1000Å), and the efficiency was 0.742%
when the material of the cathode modification layer was Bphen, with the structure of ITO/CuPc(200Å)/C60(400Å)/
Bphen(50Å)/Ag(1000Å).Using different materials as a cathode modification layer, it can be seen that the material which
matches the energy level could even eventually be able to improve the energy conversion efficiency more.
Azimuth vertical transference based on magneto-optical modulation
Li-long Tan,
Qi-yuan Zhong,
Xian-xiang Huang
Show abstract
It is a big problem that it need a large field during the missile azimuth aiming using facing upward method. Aiming to
solve the problem, it is actualized that the azimuth transfers along with the plump line. This article describes the principle
of vertical transference of the azimuth and the concrete realization of magneto-optical modulation. The scheme use the
polarized light as the medium of azimuthal information, and restrain interfere coming from azimuth transfering by
magnto-optic modulating the ploarized light. Using the technique of azimuth transfering vertically, the launching field is
reduced greatly during the missile azimuth aiming process.
Growth of ZnO nanoparticles at low temperature and optical properties
Show abstract
Zinc oxide (ZnO) has a wide direct band gap of 3.37 eV at room temperature and a large excitonic binding energy of 60
meV. In this work, ZnO nanoparticles had been successfully fabricated at low temperature (60 °C). The structures,
morphologies and optical properties of ZnO nanoparticles were investigated by X-ray diffraction (XRD), a scanning
electron microscope (SEM), UV-Visible absorption and photoluminescence (PL) spectra, respectively. Measurement
results of XRD showed that the as-prepared ZnO nanoparticles are a random orientation. The nanoparticles are
approximately particle shape with an average size of about 50 nm by SEM observation, UV-Vis absorption spectrum
indicated that the as-prepared ZnO nanoparticles dispersed in chloroform are highly transparent in the visible region and
have a strong absorption band in the UV region, at the same time, we found a sharp absorption edge at near 370 nm. In
addition, in the as-prepared ZnO nanoparticles/chloroform solution, both a near band edge (NBE) ultraviolet
photoluminescence peak at 372 nm and a defect related deep level emission (DLE) green peak at 513 nm were observed.
It suggested that the NBE photoluminescence peak should be attributed to free excitons transition, the DLE green peak
should be ascribed to intrinsic defects of the single ionized oxygen vacancy (Vo
*) through our research results.
Furthermore, we obtained R (R=INBE/IDLE) value as 0.91. This indicates that there are a large amount of single ionized
oxygen vacancies in as-prepared ZnO nanoparticles, which results in poor crystalline quality of ZnO nanoparticles.
Synthesis and luminescent properties of LaPO4:Eu3+ nanocrystal with ultrasonic method
Yanbo Wu,
Peng Sun,
Hongquan Yu,
et al.
Show abstract
It is well know that nanoscale rare earth compounds can increase luminescent quantum efficiency and display resolution.
To improve luminescent properties of nanocrystalline phosphors and obtain the nanocrystals with different morphology,
many preparation methods have been used, such as hydrothermal approach, sol-gel technique and ultrasonic method, etc.
In this paper, the LaPO4: Eu3+ nanocrystals were prepared via the ultrasonic method. There were two series prepared, by
changing ultrasonic time, using polyvinglpyrrolidone (PVP) and cetyltrimethylammonium bromide (CTAB) as template,
respectively. The morphology, structure and spectra properties of the products were characterized by scanning electron
microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared (FT-IR) and fluorescence spectrum (FS). The
results show that all the LaPO4 nanocrystals have a hexagonal structure, and without other impurity phase appearance.
All the samples obtained are nanoparticles in the range of 50-120 nm, which indicates that there are almost no effectives
on the morphology of the nanocrystals with the change of template kinds and ultrasonic time. But their luminescent
properties depend on the kinds of template. When the ultrasonic time is 1h, the luminescent intensity of the obtained
sample using PVP as template is much stronger than that using CTAB, but the 5D0 energy level fluorescence lifetime of
the Eu3+ in the sample using PVP template is shorter than that using CTAB. In addition, in the two series, luminescent
intensity increases at first, then decreases with the growth of ultrasonic time, but the 5D0 energy level lifetime of Eu3+
shows no regulation.
Texture recognition of SAR image based on surfacelet transform
Show abstract
In order to take full use of SAR image dark areas information, texture recognition method of SAR image based on
Surfacelet transform is proposed. Firstly, SAR image in test samples is decomposed into brightness SAR image and
reflection SAR image based on Retinex model; secondly, the decomposed SAR image carries through Surfacelet
transform, in order to reduce computational complexity and shorten the follow-up recognition time, the decomposed
SAR image is processed two dimension three level scale Surfacelet transform, and the first level is 8 directions, the
others are 8,2 directions respectively, after image Surfacelet transform, the sparsity of the distribution coefficient is even
more evident, especially high-frequency sub-band; thirdly, coefficient matrixes of high-frequency sub-band reduce
dimension processing by using the singular value decomposition theory of matrix; fourthly, the final eigenvector are
composed of character of energy of coefficient matrix in low-frequency sub-band and first and second-order moment of
coefficient matrix in intermediate frequency sub-band and eigenvector by reducing dimension in high-frequency subband;
at last, use BP neural network to train with supervised and recognize of samples. The method takes full use of SAR
image dark areas information, and the simulation results show that the method the recognition rate is better than other
methods.
Effect of different solvents on the performance of organic light-emitting device based on red-fluorescent ACY dye by spin coating method
Show abstract
A small-molecular red-fluorescent dye of [7-diethylamino-3-(2-thienyl)chronmen-2-ylidene]-2,2-dicyanoviny-lamine
(ACY) has been blended into blue-emitting poly(N-vinylcarbazole) (PVK) by using different solvents of chloroform and
1,2-dichloroethane. Photoluminescence characteristic of solvent effects were investigated mainly from the aspect of
solvent polarity. To demonstrate the solvent effects in organic light emitting devices (OLEDs), devices with a structure
of indium-tin-oxide (ITO)/PVK: ACY (x wt %)/tris(8-quinolinolato) aluminum (Alq3)/Mg: Ag were fabricated, in which
the weight doping ratios are x = 0.3, 0.5 and 0.7. Using spin coating method, a blending system of PVK: ACY is
dissolved in both chloroform and 1,2-dichloroethane with various doping concentrations. As a result, by choosing
chloroform as solvent, a high electroluminescent (EL) performance device with a maximum luminance of 7698 cd/m2 at
a driving voltage of 15.5 V was obtained, with a concentration proportion of PVK: ACY at 1000: 7. In the EL spectra of
the OLEDs, red and green fluorescence of ACY and Alq3 were detected. It was found that by using 1,2-dichloroethane as
a solvent, fluorescent quenching emerged with the enhancement of doping concentration. Energy transfer and Alq3
cations quencher theories were used to discuss different solvent effects on OLEDs.
Measurement of gas permeation through packaging materials of OLED by mass spectrometry
Show abstract
Mass spectrometry method was introduced to measure the gas permeability of OLED packaging materials in this paper.
Mass spectrum measuring gas permeability of barrier material have the characteristics of quick measure speed, may
measuring any gas permeability, and high sensitivity. The penetration rates and the permeability coefficient of water
vapor, oxygen and carbon dioxide permeating the encapsulation materials of OLED such as PET plastic film, UV curable
adhesive and vacuum sealing wax film have been measured by using the mass spectrometry. The results of experiments
show that the permeability coefficient of water vapor through a PET plastic film is 1.8×10-6 cm2/s, and of water vapor through UV curable adhesive is 1.2×10-6 cm2/s at temperature of 80 °C and relative humidity of 68 %. The water permeability coefficient of vacuum sealing wax at 50 °C and 92 %RH is 1.4×10-7 g/m2day. The water permeability of
vacuum sealing wax decreases an order of magnitude than that of UV curable adhesive, So Vacuum sealing wax is
suitable for the seal material in the packing of OLED than UV curable adhesive.
Efficient organic photovoltaic cells using 2-(4-biphenylyl)-5-phenyl-1,3,4-oxadiazole as an exciton blocking layer
Show abstract
By using 2-(4-biphenylyl)-5-phenyl-1,3,4-oxadiazole (PBD) as an exciton blocking layer (EBL) at the organic/cathode
interface of conventional copper phthalocyanine/fullerene (CuPc/C60) organic phtovoltaic (OPV) cells, a more efficient
OPV cell was fabricated. The electrical characteristics of OPV cells with and without PBD as an exciton blocking layer
were studied. The results showed that the power conversion efficiency (η) was increased from 0.7% to 1.58%. Also, the
dependency of the power conversion efficiency on the absorption spectra of exciton blocking layer (PBD) in OPV cells
was investigated, and it showed that the inserted PBD has almost no effect on the visible light absorption of the OPV
cell. Hence, the improved photovoltaic performance is ascribed to a more efficient charge carrier transport balance,
leading to more effective exciton separation.
Acceptor thickness effect of exciplex and electroplex emission at heterojunction interface in organic light-emitting diodes
Show abstract
Organic light-emitting diodes (OLEDs) consisted of a novel fluorene derivative of 5,6-bis(9,9-dihexyl-9H-fluoren-2-yl)-
2,3-diisocyano-2,3-dihydropyrazine (BDHFLCNPy) and a hole transporting material of N,N'-Di-[(1-naphthalenyl)-
N,N'-diphenyl](1,1'-biphenyl)-4,4'-diamine (NPB) were fabricated, and electroluminescence (EL) spectrum of devices
were investigated. It was found that light emission around 650 nm observed in devices came from exciplex generated at
heterojunction interface by NPB molecules worked as electron donor and BDHFLCNPy molecules worked as electron
acceptor. Moreover, a shoulder peak around 500 nm ascribed to BDHFLCNPy exciton was observed. To systemically
study the effect of heterojunction structure in exciplex formation, OLEDs with different thickness of acceptor were
fabricated. The results illustrated that a shoulder peak around 600 nm occurred in EL when acceptor thickness increases,
and BDHFLCNPy exciton emitting strength is relatively altered. The emission band around 600 nm is due to electroplex.
The L-V-J properties of OLEDs show that device with the thinnest acceptor layer has the highest luminance and current
density. On the contrary, OLEDs with thicker acceptor layer have higher luminance efficiency. The different
recombination mechanism of exciton, exciplex and electroplex in heterojunction were studied. Furthermore, the acceptor
thickness effect of exciplex and electroplex generating mechanism and energy transferring mechanism between them was
also discussed.
Design of driving circuit for binocular CCD image system
Show abstract
The paper designs a driving circuit of high sensitive, wide dynamic and high signal-to-noise ratio for binocular CCD
imaging system which adopts a Dalsa-made high resolution full-frame 33-mega pixels area CCD FTF5066M. Inner
structure and driving timing of the FTF5066M sensor are presented. Field Programmable Gate Array (FPGA) is used as
the main device to accomplish the timing design of the circuits and power driver control of the two sensors. By using the
Correlated Double Sampling (CDS) technique, the video noise is reduced and the SNR of the system is increased. A 12-
bit A/D converter is used to improve the image quality. The output rate of the imaging system designed with integrated
chip can reach to 1.3 frames per second through bi-channel. For its good performance, low power consumption and small
volume, the driving system can be applied to aeronautics and astronautics field. With a further improvement, a maximum
data output rate of 2.7 frames per second can be reached through all the eight channels of the two CCDs.
A study of two-point multi-section non-uniformity correction auto division algorithm for infrared images
Bo Zhou,
Yong Ma,
Hao Li,
et al.
Show abstract
Traditional two-point multi-section non-uniformity correction method for infrared imaging use fixed number of sections
and division points; this would greatly affect the algorithm's performance. In order to solve this problem, an auto
division algorithm based on slope difference of average temperature response curves of IRFPA and least square fitting
was supposed. This algorithm calculates the gradient of IRFPA's average temperature response curve and find out the
turning points, then the approximate positions of division points are decided according to given number of sections or
given threshold for slope difference; after that a least square fitting is performed in each section to produce subsection
correction lines; finally adjacent lines are connected with each other to get the complete correction curve. Experimental
results showed that the residual non-uniformity of an infrared image is greatly diminished from 0.08 % of traditional
two-point multi-section method to 0.03 %. The method is still as simple as the traditional algorithm, while the precision
of correction is significantly increased.
New LED illumination optical engine for micro-projection display
Show abstract
A new optical engine consisting of LEDs, rectangular CPC, rectangular lens array and micro display chip DMD is
designed by using of KOLA illumination algorithm for micro-projection display. Detail description and analysis of the
rectangular CPC and rectangular lens array are provided. The influence due to the size of rectangular CPC and
rectangular lens array is analysed for illuminance uniformity on the DMD chip and light energy efficiency of the optical
engine system by software ZEMAX. Based on the analysis of parameter of rectangular lens array, the size of rectangular
lens array more decrease the illumination uniformity. Experimental results show that the proposed illumination light
optical engine can obtain perfect rectangular focula with higher light uniformity more than 90 % and higher energy
efficiency of 40 % to meet the needs of micro-projection display, at the same time the designed illumination optical
engine compared with other uniformizing light algorithm have advantages such as: lesser capacity, high illumination
uniformity.
Efficiency improvement of yellow organic light-emitting devices by using mixed hole transporting layer
Sujie Chen,
Junsheng Yu,
Wen Wen,
et al.
Show abstract
Organic light-emitting devices (OLEDs) with a novel metal iridium complex of bis[2-(4-tertbutylphenyl)
benzothiazolato-N,C2'] iridium (acetylacetonate) [(t-bt)2Ir(acac)] doping into a carbazole-based material
4,4'-bis[N-1-napthyl-N-phenyl-amino]biphenyl (CBP) as light-emitting layer (ETL) were fabricated. The optimum
doping concentration of (t-bt)2Ir(acac) phosphor was 8 wt%. The maximum power efficiency (ηp) of the OLED was 8 lm/W. Furthermore, to improve the balance of charge carriers and enhance the ηp of the device, a doping system consisted of NPB hole transporting material and CBP host material with a concentration proportion of 1:3 was employed
as the mixed hole transporting layer. OLEDs with a structure of indium-tin oxide (ITO)/N,N'-bis-(1-naphthyl)-N,N'-
biphenyl-1,1'-biphenyl-4,4'-diamine (NPB):CBP(1:3)/CBP:(t-bt)2Ir(acac)/2, 9-dimethyl-4, 7-diphenyl-phenanthroline
(BCP)/Mg:Ag were fabricated. The results showed that current density was decreased and the maximum ηp of the device was 10.6 lm/W. Compared with the conventional device with NPB as hole transporting layer, the improved maximum ηp of the device with mixed hole transporting layer was increased 32.5 %. This is attributed to the reduction of hole injection amount and transporting mobility by doping material CBP in hole transporting layer, which significant enhances charge carrier balance and electron-hole recombination probability.
Contrast study on GaAs photocathode activation techniques
Show abstract
At present, two kinds of activation techniques for preparing GaAs NEA photocathode are available. In this paper,
according to two kinds of photocurrent curve arising in the activation, the characteristic and mechanism of the two kinds
of craft were summed up and compared with each other, and the further theoretical investigation on the mechanism of
activation was carried out based on the recent research of NEA surface model for GaAs photocathode. It is proposed as a
process principle that during (Cs, O) alternation phase of the activation process of GaAs photocathode, Cs should always
be in excessive state. Besides, it is also indicated that whether Cs is excessive during (Cs, O) alternation phase and the
Cs/O ratio may affect directly the final property of photocathode. Finally, a method to modify the craft parameters to
guard against the deviation from the principle is presented. The presented study is very necessary and significative for
optimizing the activation techniques so as to enhance the performances of GaAs NEA photocathodes.
Spectral response variation of exponential-doping transmission-mode GaAs photocathodes in the preparation process
Show abstract
The exponential-doping structure was applied to prepare the transmission-mode GaAs photocathode, and spectral
response curves after high-temperature activation, low-temperature activation and the indium sealing process were
respectively measured by use of the on-line spectral response measurement system, to research into the practical effect of
the exponential-doping structure on cathode performance. The results show that a high photosensitivity ranging from 560
nm to 880 nm with an ascending trend can be obtained after the high-low temperature activation. In the region of longwave
threshold, there is a distinct inflexion indicating a better photoemission capability than the former uniform-doping
photocathodes. Besides, the spectral response curve in the whole response waveband, especially the long-wave region
obviously decreases after indium seal. Compared with the fitted surface electron escape probability after Cs-O activation,
it decreases after indium seal according to the quantum efficiency formula of exponential-doping transmission-mode
GaAs photocathodes. Based on the double dipole model, the reasons for the variation of spectral response shape are
explained on account of the relation between surface escape probability and the evolution of surface potential barrier
profile.
Properties of photoelectricity of WOx-doped ITO thin films
Ye Liu,
Zhuying Li,
Chong Wang,
et al.
Show abstract
Indium-tin-oxide (ITO) film is an n-semiconductor transparent conductive film. It has many good properties:
conductivity, transmittance in visible region, absorptivity in ultraviolet. And tungsten oxide has good conductivity and it
can keep stable structure in high temperature, also it has wearable and anti-corrupt properties. Therefore, tungsten oxide
can be added gradually on ITO thin films by magnetron sputtering to research the optical and electrical performance of
the doped films. We research the performance of the doped films in five aspects: X-ray diffraction spectroscopy,
Scanning electron microscope are used to investigate the crystal structure, surface morphology. UV-visible spectroscopy
is used to display the transmittance and absorption spectrum of the films. The thin films' performance of
electrochemistry is tested by the workstation of electrochemistry. Its conductivity is tested by Four-probe sheet resistivity
meter. The main conclusion: The analysis of SEM results shows that the surface morphology of the films is granulated.
Transmittance spectrums suggest that the transmittance of ITO films have been increased by proper doping, the
percentage of transmittance is over 90% from visible to near-infrared region. Besides, it shows well in the properties of
electricity and electrochemistry in the doped films.
An objective assessment method of digital image mosaic artifacts visibility based on visual perception
Show abstract
The difference of illumination between to-be-mosaicked images will cause mosaic artifacts when digital images are
mosaicked. An objective assessment method of digital images mosaic artifacts visibility based on human visual
perception has been studied in this paper. The process of the method are as follows; 1) the gradient errors image is
obtained according to the to-be-mosaicked images, 2) the just noticeable difference (JND) of reference image is
derived by considering the human visual frequency sensitivity, the brightness mask effects and texture mask effects on
visual resolution comprehensively; 3) the mosaic artifacts image which is perceptible visually can be acquired by
subtracting the JND threshold values from the wavelet coefficients of gradient errors image in wavelet domain. The
mosaic artifacts visibility (MAV) of digital image is constructed to use as an objective assessment index of image
stitching seam visibility by considering the average value and information entropy of the mosaic artifacts image
comprehensively. The experiment indicates that the objective assessment results of digital image mosaic artifacts
visibility by MAV index are consistent with those of the subjective perceptual method basically.
Research on APD-based non-line-of-sight UV communication system
Rongyang Wang,
Ling Wang,
Chao Li,
et al.
Show abstract
In this paper, specific issues in designing an avalanche photodiode (APD)-based non-line-of-sight (NLOS) ultraviolet
(UV) communication system are investigated. A proper wavelength of the UV LEDs and a system configuration should
be considered carefully to assure the feasibility of this system. Using the single scattering model, the received optical
power at the sensitive area of the APD can be calculated. According to the calculation, it revealed that the scattered
ultraviolet signal level was very low; therefore, a post signal processing circuit was necessary. The authors put forward
the key components of the circuit based on the compromise between signal bandwidth and gain. The performance of this
circuit was evaluated by means of software simulation, and continued work was involved to improve its signal noise ratio
(SNR). The transmitter used in this system was 365 nm UV LED array. Strictly speaking, this was not the practical
outdoor UV communication system. Since the scattering coefficient of 365 nm UV only drops a little compared with
solar blind UV, the research-grade UV communication could be carried out in a darkroom without a great influence. By
combining an APD with a compound parabolic concentrator (CPC) optical system, the effective collection area and field
of view (FOV) of the detector could be adjusted. Several issues were also raised to improve the performance of UV
communication system, including using more powerful UV LEDs and choosing suitable modulation schemes.
Study on the experiment of cable tension measurement with FBG sensors
Show abstract
Fiber Bragg Grating (FBG) sensors sense the change of temperature or strain by detecting the wavelength shifted
reflected by the Bragg grating carved on a fiber. Aiming at measuring tension of cables, we did a lot of experiments with
FBGs, testing its loading characteristics, temperature response, repeatability, consistency of different sensors, and long
term stabilization. When analyzing data, we find that environment temperature has a serious influence to the result. So
we use temperature compensation with a temperature sensor. Then we proceeded same experiments with traditional force
sensor under the same condition, compared their result and analyze the advantages and disadvantages of the two kinds of
sensors in the measurement of cable tension. At last, we made some prospect on FBG using on cable tension
measurement.
Photoluminescence of Mn+ doped GaAs
Huiying Zhou,
Shengchun Qu,
Shuzhi Liao,
et al.
Show abstract
Photoluminescence is one of the most useful techniques to obtain information about optoelectronic properties and defect structures of
materials. In this work, the room-temperature and low temperature photoluminescence of Mn-doped GaAs were investigated,
respectively. Mn-doped GaAs structure materials were prepared by Mn+ ion implantation at room temperature into GaAs. The
implanted samples were subsequently annealed at various temperatures under N2 atmosphere to recrystallize the samples and remove
implant damage. A strong peak was found for the sample annealed at 950 °C for 5 s. Transitions near 0.989 eV (1254 nm), 1.155 eV
(1074 nm) and 1.329 eV (933 nm) were identified and formation of these emissions was analyzed for all prepared samples. This
structure material could have myriad applications, including information storage, magnet-optical properties and energy level
engineering.
Photostimulated luminescence of BaFCl:Eu2+ in oxide glass ceramics
Xianguo Meng,
Ji Zhou
Show abstract
Oxide glass ceramics with different concentrations of BaFCl:Eu2+ doping have been prepared. Photoluminescence (PL)
and photostimulated luminescence (PSL) after x-ray irradiation were observed at room temperature. The PSL was
attributed to the characteristic emission of Eu2+ in crystallites of BaFCl, which formed in the glass. Increasing the
concentration of BaFCl:Eu2+ causes an increase in PSL conversion efficiency , but a decrease in transparency. The tradeoff
between optical transparency and PSL intensity over different concentrations of BaFCl for X-ray imaging plate
applications was briefly discussed.
A novel design of infrared focal plane array with digital read out interface
Xiaoyang Liu,
Ruijun Ding,
Wei Lu,
et al.
Show abstract
Infrared focal plane array (IRFPA) with digital read out interface is a key sign of the third generation IRFPA, which
plays an important role in the reliability and miniaturization of infrared systems. A readout integrated circuit (ROIC) of
IRFPA with digital readout interface based on dual ramp single slope (DRSS) analog to digital converter (ADC)
architecture is presented in the paper. The design is realized using shared ADCs in column-wise and these ADCs are
consisted of simplified DRSS architecture and shared units. Sample, conversion and readout are proceeded
simultaneously in order to adapt large scale and high readout frame rate application. This circuit also shows many
advantages, including small area and low power consumption. Simulation result shows that this architecture can be
expand to 320×256 pixel array with a frame rate of 100 frames per second or a larger size whit lower frame rate, the
quantized resolution of this circuit is 12 bit, and the analog power consumption is only 17μw per ADC.
Reliability studies of high operating temperature MCT photoconductor detectors
Show abstract
This paper concerns HgCdTe (MCT) infrared photoconductor detectors with high operating temperature. The near room
temperature operation of detectors have advantages of light weight, less cost and convenient usage. Their performances
are modest and they suffer from reliable problems. These detectors face with stability of the package, chip bonding area
and passivation layers. It's important to evaluate and improve the reliability of such detectors. Defective detectors were
studied with SEM(Scanning electron microscope) and microscopy. Statistically significant differences were observed
between the influence of operating temperature and the influence of humidity. It was also found that humility has
statistically significant influence upon the stability of the chip bonding and passivation layers, and the amount of
humility isn't strongly correlated to the damage on the surface. Considering about the commonly found failures modes in
detectors, special test structures were designed to improve the reliability of detectors. An accelerated life test was also
implemented to estimate the lifetime of the high operating temperature MCT photoconductor detectors.
Etch-induced damage of HgCdTe caused by inductively coupled plasma etching technique
Wenting Yin,
Wenzhong Zhou,
Jian Huang
Show abstract
HgCdTe third-generation infrared focal plane arrays such as avalanche photodiodes, two-color detectors and multi-color
detectors require isolation of high aspect ratio trenches with admissible etch induced damage at the surface and
sidewalls. Dry etch has many advantages compare with wet etch such as high anisotropy, good uniformity and good
reproducibility. Inductively coupled plasma (ICP) etching is most widely used for its low etch induced damage which is
a new high density plasma technique.
It's very important to understand etching mechanisms and reduce etch induced damage for the low damage threshold of
HgCdTe which is due to weak Hg-Te bond and low volatility of CdTe component. The main work of this paper is
researching the influence of etch induced damage caused by different mask technique using inductively coupled plasma
etching instrument with a feasible technics. In this experiment we used two different masks, one only has a film of silicon
dioxide which we called thin mask, its thickness is less than one micrometer, and the other is composed of resist and
silicon dioxide which we called complex thick mask, its thickness is several micrometers. We tested the current-voltage
(I-V) characteristics of a chip which has a special structure achieved by dry etch and about one micrometer wet etch to
remove the etch induced damage film. Then we found that in a same condition the I-V characteristics of the chip which
used complex thick mask is distinctly better than the chip which used thin mask. Resist and silicon dioxide complex
thick mask can effectively reduce etch induced damage. The reasons for this result have two aspects, in one hand, the
grown process of silicon dioxide can cause damage of HgCdTe surface, make a thick resist between HgCdTe and silicon
dioxide can reduce the damage of HgCdTe surface, in the other hand, complex thick mask can hold up the damage of
trench sidewall in etch process.
Effects of solution properties on the morphology and diameters of nanofibers fabricated by electrospinning
Show abstract
In this paper, four different series of polymer solutions were presented to study the effects of solution properties on the
morphology and diameters of nanofibers, including the polyethersulfone (PES) dissolving in N, N-dimethylformamide,
polyvinylpyrrolidone (PVP) in ethanol, poly(acrylic acid) (PAA) in water and poly(vinylidene fluoride) (PVDF) in N, Ndimethyl
acetamide. These solutions revealed different conditions of the formation of beads, the spatial structures and the
diameter of fibers. The PVDF nanofibers had plenty of small beads on the fibers, while the other three were uniform
fibers without beads. The nanofibers of PES, PVP and PVDF showed good three dimensional structures except the PAA
fibrous membranes. The change of fiber diameters of PVDF was much larger than that of PVP.
Research of a high-efficiency practical distributed fiber Bragg grating temperature sensor system
Yanjun Zhang,
Bo Wei,
Junbo Lou,
et al.
Show abstract
A novel practical distribute Fiber Bragg Grating sensor system is presented in this paper. When the bandwidth of the
broadband light source is 300 nm, the whole system can monitor more than 1000 meters and it is divided into 100
sections. Each section has 4 gratings with identical center wavelength, and these identical gratings monitor a small zone.
The center wavelength of grating will shift due to temperature changes. By detecting the reflected light, the change of
temperature and the location can be obtained. The system will alarm if this temperature is over setting value. A high-precision
optoelectronic detector is used to detect the optical power, and the resolution is 1 nw. Based on the theory
analysis, temperature experiments of different wavelength have been done. Based on the ARM Processor Cores, we
designed an optimized algorithm which encoded all gratings and coordinated Fabry-Perot (F-P) tunable filter and
optoelectronic detection system synchronously. The accuracy of the algorithm is up to 10 μs. The results show that
grating center wavelength varies with temperature and linearity is over 99.6 %. The system not only can realized the
temperature measurements but also expand the monitor range. It has been seen in experiments that the characteristics of
the measured precisions of good reliability and high efficiency, application in distributed multimetering.
Infrared non-uniformity correction algorithm based on fast independent component blind separation
Show abstract
Going with Infrared Focal Plane Array (IRFPA) development, the application of infrared imaging system is more and
more extensive, it's well known that the Non-Uniformity Correction (NUC) is the only necessary data soft processing in
the whole infrared imaging data link, it will be seen from this that the NUC quality stand or fall influences the final
imaging product quality directly, for target detection and identification system, it increases the complexity and timeliness
of the target detection and identification algorithm undoubtedly. Currently, the Non-Uniformity Correction (NUC)
algorithm can be divided two classifications: the one is that Non-Uniformity Correction based on calibration source, this
algorithm assumes the infrared system response characteristic is linear, takes the dark current and gain as the two
correction parameters, but for nonlinear, especially for the response drift characteristic and the ambient temperature
change, the higher the system sensibility is, the greater the influence is and the higher the design requirements for system
stray radiation are. The correction effectiveness is limited seriously; the another is adaptive correction algorithm based
on scene (SBNUC), it can be subdivided time domain, space domain and motion estimation processing algorithms,
although it do not need physical calibration source and also reduces the influence of system response drift to a certain
degree, but the requirement is rigorous for statistics specimen and size, and the rapidity of convergence and stability are
different.
In this paper, according to blind information source decomposition technique, the infrared image is divided to signal and
noise as two information sources, a new Non-Uniformity Correction method based on Fast Independent Component
(FastICA) blind separation is put forward. By means of the experimental contrast analysis for the linear correction
algorithm and constant statistics algorithm of real infrared image, by this new algorithm, the influence of the system
response drift and the ambient temperature change for the linear correction algorithm based on physical calibration
source is not only suppressed, but also the shortages of the scene-based Non-Uniformity correction (SBNUC) in statistics
specimen and size are overcome partly. The experimental result proved the effectiveness of this algorithm in the paper
which effectively separated the signal and noise of the infrared image. At the same time, the algorithm in the paper
supplied a new solution of Non-Uniformity Correction (NUC) by the experiment.
Application research of fault diagnosis expert system for photoelectric tracking device based on BP NN
Show abstract
In order to overcome the deficiencies of poor adaptive capacity, lack of inspiration and narrow domain knowledge of
expert system and fundamentally improve the diagnostic efficiency, an intelligent fault diagnosis expert system for
photoelectric tracking devices, based on BP neural network, is put forward. Firstly, in this paper, some key basic
concepts and principles of intelligent fault diagnosis technology are proposed. Secondly, according to the difficulty of
multiple and coupling fault diagnosis, after making a comparative analysis of the related BP neural network algorithms,
such as the quasi-Newton method, the stretch BP method and the conjugate gradient method, a neural network fault
diagnosis reasoning method based on the Levenberg-Marquardt is designed, which combined the implementation of the
diagnosis expert system. Finally, several interrelated essential implementation issues, such as the architecture of the
system and the VR technology based on OpenGL, are also discussed. Practical experiments and applications demonstrate
that the proposed approach is effective, robust and universal.
Distinguishing different parts of objects by terahertz imaging
Jin Ge,
Reng Wang,
Shuhong Hu,
et al.
Show abstract
Since every matter has its distinctive absorption and transmission capacity of terahertz, Terahertz time
domain spectroscopy provides a powerful means to distinguish the different parts of objects. The
transmittance of terahertz under different frequency can reflect the absorption distribution of the
different parts of the samples. The phase shift of the terahertz wave indicates the change of optical
thickness of the sample. Tree leaves, plastic ring, plastic convex lens and plastic piece with a small
hole have been imaged by terahertz. As widespread samples, leaves are proved to be well imaged by
terahertz wave. For the moisture content at different parts of leaves, such as mesophyll and vein, is
not the same, the absorption of terahertz at these parts are quite different. At 1.4THz, the leaf's image
is of good quality and the vein grids are well shown. The hole and defects in the plastic ring are also
clearly shown in the THz image because the phase shifts of terahertz in different parts, such as air,
defects or plastic region are not the same. It is also shown that objects with large radius of curvature
are suitable for THz imagining and the scattering of THz does not affect THz phase information too
much. In short, Terahertz imaging is a powerful technique to distinguish the different parts of most
objects as long as the absorption of THz is not very strong.
Fabrication and evaulation of the CdZnTe microlens arrays
Jian Huang,
Wenhong Zhou,
Wenting Yin
Show abstract
This paper presents a modified thermal reflow process to fabricate CdZnTe (CZT) microlens arrays and a new
convenient method to evaluate the quality of the microlens. In the fabrication experiment, square photoresist (PR)
isolated-islands with almost zero gap each other were formed on a CdZnTe substrate by the underexposure
photolithographic process firstly. Then, high fill-factor (almost 100 %) PR microlens arrays were generated via thermal
reflow the islands at 110 °C for 30 minutes. Finally, through etching the substrate using the PR microlens arrays as the
mask by an inductively coupled plasma (ICP) dry etching process with Ar/N2/CH4 gas, the high fill-factor CdZnTe
microlens arrays were achieved. Besides, a new convenient method to evaluate the quality of the microlens was also
established in this paper. At the first step of the evaluation, the data of surface topography of the microlens fabricated
was recorded by the confocal scanning laser microscope (CSLM). Then, the characteristic of the microlens such as the
surface topography, focusing properties, the light intensity distribution of the microlens, etc. was simulated and displayed
by the procedure base on the CZT optical parameters and the data of the actual surface topography of the microlens. The
results show that the microlens fabricated by the modified thermal reflow process can focus 80 % incident light of the
pixel on the 30 % central region, with only 1.6 % optical crosstalk.
Influence of doping I2 into MEH-PPV on carrier transporting capability and electroluminescence properties
Zhiming Cheng,
Fujun Zhang
Show abstract
The current-voltage characteristics and electroluminescence (EL) spectra were studied with different I2 doping
concentration in MEH-PPV based on single layer and double layer organic light emitting diodes (OLEDs). For the single
layer devices, EL intensity and current was increased with the doping concentration under the same driving voltage. For
the double layer devices, the charge carrier recombination zone was controlled by the different I2 doping concentration
compared to these devices without doping. The variation of EL spectra was discussed from the improvement of hole
mobility in MEH-PPV layer induced by I2 doping into it.
Non-uniformity correction for infrared focal plane array with image based on neural network algorithm
Show abstract
Non-uniformity response of detectors based on infrared focal plane array (IRFPA) result in fixed pattern noise (FPN) due
to detector materials' non-uniformity and fabrication technology. Once fixed pattern noise added to the infrared image,
focal plane image quality will have a serious impact. So non-uniformity correction (NUC) is a key technology in IRFPA
application. This paper briefly introduces the traditional neural network algorithm and puts forward an improved
algorithm for the neural network algorithm for NUC of infrared focal plane arrays. The main improvement is focused on
the estimation method of desired image. The algorithm is used to analyze the image array, correcting data on the array
both in space and in time. The correction image in the text is from the infrared data sequence which is more successful of
three frames of data obtained. It was found that the estimated image corrected by new algorithm is closer to real image
than the estimated image corrected by other algorithm. Moreover, we simulated the new proposed algorithm using
Matlab. The results showed that the method of spatial and temporal co-correction of the images is more realistic than the
original image.
Effective local-field confinement of silver nanoparticle dimer arrays
Li Yao,
Xufeng Li,
Tiangang Yang,
et al.
Show abstract
The optical properties of silver spherical nanoparticle dimer arrays with various incident wavelength are investigated by
using the finite difference time domain method. Due to surface plasmon resonance, in the arrays of strongly coupled Ag
nanoparticles, the energy of incident light is effectively confined in the gap of penultimate dimer under the influence of
surface plasmonic reflection at the end of array structure. Furthermore, the suitable radius of the nanoparticles can be
chosen to obtain the resonant peak at the optional position in the range of visible-nearinfrared wavelength. The above
effects can be utilized to design effective functional end-structures in integrated optics.
The influence of substrate temperature on the electrical and optical properties of titanium oxide thin films prepared by d.c. reactive magnetron sputtering
Show abstract
In this investigation, a novel heat-sensitive material titanium oxide (TiOx) thin film was deposited on well cleaned K9 glass substrates by d.c. reactive magnetron sputtering from a metallic titanium target in an Ar + O2 gas mixture. In order to obtain proper TiOx thin films, deposition parameters should be properly controlled. In our system, TiOx thin films were obtained at different substrate temperature while total pressure and oxygen partial pressure were kept at 1 Pa and 0.6 Pa, d.c. power of 100 W, and the deposition time was adjusted in order to deposit thin films with a constant thickness close to 200 nm. The crystalline structure was characterized by X-ray diffraction (XRD) analysis and the results show that all the deposited films have an amorphous structure. In this paper, we have mainly investigated the dependence of electrical and optical properties of the reactively sputtered TiOx thin films on the different substrate temperature during the sputtering process, i.e., as the K9 glass substrate temperature increases from 100 °C to 250°C, the sheet resistance Rs of TiOx thin films is ranged from 305 kΩ/square to 36 kΩ/square, temperature coefficient of resistance (TCR) value up to -2.12 %/K is obtained, optical band gap decreases from 3.34 eV to 3.28 eV. Through the analysis and discussion of the above experimental data, we could obtain the conclusion that the variation in substrate temperature during the sputtering deposition plays a considerable important role in the electrical and optical properties of all the deposited films.
Research of laser active image-denoising method
Show abstract
In this paper, an image-denoising method is presented based on mathematical morphology and wavelet transform. Highfrequency
coefficients are processed by mathematical morphology firstly. Then, according to the respective
characteristics, high frequency sub-band images at horizontal, vertical and angular directions are denoised by three
different filter templates after wavelet transform. We take measures to protect edge information and detail of image.
Experiment result shows that the noise of the image is removed effectively. At the same time, the detail of the image is
kept well. The method has better denoising effect.
A back-illuminated heterojunctions ultraviolet photodetector based on ZnO film
Xiandong Jiang,
Dawei Li,
Wenjun Yang,
et al.
Show abstract
In this paper, we present the investigation of a back-illuminated heterojunctions ultraviolet detector, which were fabricated by depositing Ag-doped ZnO based (ZnO-TiO2) thin film on transparent conductive layer of ITO coated quartz substrate though the reactive radio-frequency (RF) magnetron sputtering at higher oxygen pressure. The p-n junction characteristic is confirmed by current-voltage (I-V) measurements. The turn-on voltage was 6 V, with a low leakage current under reverse bias (-5 V), corresponding values was just 0.2 nA . It is clearly showed the rectifying
characteristics of typical p-n junction's rectifier behaviors. The structural, component and UV (365 nm, 1400 μW/cm2)
photoresponse properties were explored by X-ray diffraction (XRD), Scanning Electron Microscope (SEM), X-ray energy dispersive spectrometer (EDS) and Tektronix oscilloscope. The results showed that: Ag in substitution form in the ZnO lattice, Ag doping concentration is low, the sample is highly c-axis preferred orientation, With the increase in doped Ag volume, ZnO film of 002 peaks no longer appear. The surface of the Ag doped ZnO based film exhibits a smooth surface and very dense structure, no visible pores and defects over the film were observed.The ultraviolet response time measurements showed rise and fall time are several seconds Level.
Design of the acquisition system with low-noise based on 160×120 uncooled infrared detector
Yanmin Xing,
Yun Zhou
Show abstract
This paper discusses the importance of the Uncooled infrared focal plane array detector with low noise, and focuses on
solving the hardware problem - how to reduce the noise of the detector by the technique of I2C and differential input.
Meanwhile the hardware circuitry should meet the driving conditions. Beside of this, the author aims to describe the
method using in reducing the noise of the detector driver circuit, the quantization noise of the A/D circuit, removing the
image background noise, non-uniformity correction and so on. Moreover, the author analyzes the noisy level of each part
of the circuitry in theory, and obtains the RMS and SNR of the practical image. The results show that: the acquisition
system is working properly and has a comparably low noise performance. The RMS noise of the acquisition system is
568 μV, and the SNR reaches over 60 dB under the blackbody irradiation and the room temperature.
Design of high-speed low-noise pre-amplifier for CCD camera
Xucheng Xue,
Shuyan Zhang,
Hongfa Li,
et al.
Show abstract
Pre-amplifier circuit is critical for the noise performance of the high speed CCD camera. Its main functions are
amplification and impedance transform. The high speed and low noise pre-amplifier of CCD camera is discussed and
designed in this paper. The high speed and low noise operational amplifier OPA842 is adopted as the main part. The
gain-set resistors for the amplifier are designed optimally. The different precision gain-set resistors are swept using
Monte Carlo method. CCD video signal which has high DC offset voltage is AC coupled to the amplifier. The output
signal of the amplifier is source terminated using 50 ohms matching resistor so as to transmit the video signal through
coaxial cable. When the circuit works in high speed, the PCB will have important effect to circuit performance and can
even cause the amplifier unstable due to the parasitic problem of PCB. So the parasitic model of the PCB is established
and the PCB layout design issues are also presented. The design result shows that the pre-amplifier can be used in the
camera whose pixel rate could be up to 40 MHz and its input referred noise density is about 3 nV/Hz1/2.
High-efficient and brightness white organic light-emitting diodes operated at low bias voltage
Lei Zhang,
Junsheng Yu,
Kai Yuan,
et al.
Show abstract
White organic light-emitting diodes (OLEDs) used for display application and lighting need to possess high efficiency,
high brightness, and low driving voltage. In this work, white OLEDs consisted of ambipolar 9,10-bis 2-naphthyl
anthracene (ADN) as a host of blue light-emitting layer (EML) doped with tetrabutyleperlene (TBPe) and a thin codoped
layer consisted of N, N'-bis(naphthalen-1-yl)-N,N'-bis(phenyl)-benzidine (NPB) as a host of yellow light-emitting
layer doped with 4-(dicyanomethylene)-2-tert-butyl-6-(1,1,7,7-tetramethyljulolidin-4-yl-vinyl)-4H-pyran (DCJTB) were
investigated. With appropriate tuning in the film thickness, position, and dopant concentration of the co-doped layer, a
white OLED with a luminance yield of 10.02 cd/A with the CIE coordinates of (0.29, 0.33) has been achieved at a bias
voltage of 9 V and a luminance level of over 10,000 cd/m2. By introducing the PIN structure with both HIL and bis(10-
hydroxybenzo-quinolinato)-beryllium (BeBq2) ETL, the power efficiency of white OLED was improved.
The spectral adaptation applied to image color appearance model
Show abstract
The major aim of Color Appearance Model is trying to resolve the problem of high faithful color reproduction under
different viewing conditions, which is one of the main mathematical methods fulfilling the cross-media color production.
Currently used Color Appearance Model (CAM) based on von Kries chromatic adaptation transform, that is, CAM acts
upon chromatic signals such as tristimulus values rather than spectral characteristics. The spectral adaptation model
introduced by Fairchild in 2006 based on the spectral reflectance factor of stimulus and the spectral power distribution
function of light source. The new way models the vision phenomenon with no requirement for the chromatic processing.
Munsell color chips are used as basic data. Spectral adaptation model and CIELAB color space are employed to predict
corresponding color appearance attributes. Then the comparison to CAT02 chromatic adaptation transform is also made.
The result shows that spectral adaptation model has a high degree of accuracy in lightness performance, and the relative
error is between 2 % and 5 %. But the accuracy of chroma is less than CAT02, and both models have good uniformity in
hue performance. Taking the image color appearance model as the carrier, the spectral adaptation model is applied to the
image reproduction. The methods are used to model the image with no requirements for the CAT02 chromatic adaptation
processing and to use spectral adaptation as pretreatment, then to carry out the chromatic adaptation transformation.
Discussion of the advantages and limitations of the model and the practical value in image rendering is also presented.
Novel structure for ultrafast uncooled focal plane array
Zhengxi Cheng,
Bin Ma,
Xuemin Zhang,
et al.
Show abstract
A novel structure combining normal uncooled focal plane array (UFPA) microbridge and RF MEMS switch is presented.
The MEMS switch is integrated into the microbridge without any modification of the microbridge structure and
fabrication process. The upper electrode of the switch is the IR absorbing layer of the microbridge, and the down
electrode is the reflecting mirror of the IR resonant chamber on the substrate. With the help of the MEMS switch, the
microbridge can be pulled down to the substrate, and be cooled to the substrate temperature T0. Correlated double
sampling(CDS) method is used to read out the difference between R(T0) and R(T1), where R(T0) is the value of
thermistor on the microbridge when the microbridge is pulled down to the substrate, and cooled to the substrate
temperature T0, and R(T1) is the value of thermistor when the microbridge is heated up to T1 by radiation after the
microbridge is released from the substrate for a certain short time. The difference between R(T0) and R(T1) is just
related to thermistor R itself, and no reference resistor is need. Match between the thermistor and its reference in normal
structure, which is the most difficult task in fabrication, is no longer existed. And the signal due to mismatch between the
thermistor and the reference resistor, which is very large compared with the signal due to the thermistor change, and
which often makes op saturated, also no long exists. In CDS read-out circuit, the difference between R(T0) and R(T1)
can be very small, which cannot approximate thermal equilibrium state. So it only needs a very short time for the
microbridge to absorb radiation. The simulation results show that this novel structure can work up to 10KHz without any
performance decrease, which is 100 times faster than the speed of the normal structure.
Fabrication of black silicon materials by wet etching and characterization
Zhengyu Guo,
Zhiming Wu,
Anyuan Zhang,
et al.
Show abstract
In this paper we use Si3N4 membrane acting as mask in fabrication of black silicon by wet etching technique, and the
sample have nearly 90% absorptance at wavelength from 250 nm to 1000 nm. The experiments result shows that Si3N4
membrane as mask wet etching technique for fabrication of black silicon is feasibility, and has much more advantages
compared to fabrication of black silicon by using femtosecond laser, RIE and hydrothermal etching. It provides a proper
and economical method for fabrication of black silicon visible and near-infrared optoelectronic devices.
Effects of annealing on InAsSb films grown by the modified LPE technique
Changhong Sun,
Shuhong Hu,
Qiwei Wang,
et al.
Show abstract
We have studied the annealing effects on InAsSb thick films grown by the modified liquid phase
epitaxy (LPE) technique. Appropriate annealing treatment can efficiently eliminate Sb vacancy and
stain which are formed during growing process, thus it is necessary to study the influence of annealing
condition (temperature, ambient, time and cooling rate) on the properties of InAsSb epilayer. The X-ray
diffraction measurement (XRD) showed the annealed InAsSb films were polycrystalline with
(111)-preferred orientation, except for the two samples annealed with 350 °C for 15 hours and with
rapid cooling rate, respectively, which exhibited a (100)-preferred orientation. The Fourier transform
infrared (FTIR) revealed a cut off wavelength more than 10 μm for the samples. Also, the infrared
transmittance would be improved due to decreasing of film defects by appropriate annealing treatment.
Measurement of electrical properties for samples revealed the increase of electron mobility and the
reduce of carrier concentration at 77K when keeping anneal temperature low at 350 °C and extending
anneal time, indicating the electrical improvement of the InAsSb layers.
Preparation and mechanism of carbon encapsulated Cu nanoparticles
Show abstract
In recent years, research interests in copper nanoparticles have been increased significantly due to their excellent
performance in tribology, catalysis and many other fields. However, their applications have been still limited because the
bare nanoparticles are easily oxidized. Therefore, the study of copper nanoparticles encapsulated in carbonaceous shells
is an important issue. In this study, the carbon encapsulated copper nanoparticles were prepared using copper nitrate as
the metal sources and using sucrose as the carbon sources, through reducing and annealing. The phase, morphology,
particle size and structure of as-prepared samples were characterized using X-ray diffraction, field emission transmission
electron microscopy, scanning electron microscopy and Raman spectroscopy, respectively. The results indicate that the
samples exhibit well core/shell structure, with sphere form and uniform size (50 nm in average). The copper cores
consists of polycrystalline particles with fcc structure, whose size varies from 20 nm to 60 nm. The shell is amorphous
carbon and its thickness is about 10 nm. In addition, the formation mechanism of carbon encapsulated copper
nanoparticles was discussed and presented in the paper.
Studies of a colorimetric array consisted of metalloporphrins and Pt complexes
Jing Luo,
Tengshuang Ma,
Lu Li,
et al.
Show abstract
We have studied the absorption of volatile organic compounds (VOCs) and vapochromic characterization by a
colorimetric array based on metalloporphyrins and Pt complexes: ZnTPP, CuTPP, and [Pt(Me2bizmpy)Cl]Cl
(TPP=tetraphenylporphrins; Me2bzimpy=2,6-bis(N-methylbenzimidazol-2-yl)pyridine). The array was exposed to
pyridine, tetrahydrofuran, ethyl acetate, methanol and acetonitrile. The experimental results demonstrate that the Pt
complexes are sensitive to methanol and acetonitrile, while ZnTPP and CuTPP present an obvious response to pyridine,
tetrahydrofuran and ethyl acetate. The response behaviors are reversible and rapid within seconds. The changes of Ultra
Violet Visible (UV-visible) absorption spectrums of ZnTPP and CuTPP LB films before and after exposure upon the
VOCs are also discussed. In addition, the differences of absorption spectrum of Pt complexes dissolved in several
solvents are mentioned. The results show that [Pt(Me2bizmpy)Cl]Cl, CuTPP and ZnTPP exhibit reversible changes of
action with VOCs, and they show promising future to be used in Smell-Seeing Electronic Nose to identify VOCs.
A novel colored electrophoretic core/shell particles prepared by precipitation polymerization
Yuguang Feng,
Feng Teng,
Shihua Huang
Show abstract
In one bath 3 stages process, Surface-ionized core with pyridinium was dyed separately with ordinary red, green, blue
acid dyes, and was changed into color microsphere. The shell polymer with epoxy group was prepared to reduce travel
resistance, and then the colored electrophoretic particle was obtained by means of ionizing the core-shell microsphere.
After the microsphere was characterized by DSC, TG, FTIR and SEM, zeta potential of electrophoretic particles
dispersed in organic solvents was tested and changed regularly with particle size and concentration.
Subpixel edge-detection algorithm based on pseudo-Zernike moments
Show abstract
In order to meet the demands of high precision localization and anti-interference performance for optoelectronic
detection and imaging devices, a new subpixel edge detection approach based on orthogonal Pseudo-Zernike moments is
proposed in this paper with both theoretical analysis and experimental demonstration. First, the ideal step model of
subpixel edge is established, and the specific characteristics of edge points can be extracted through the convolution with
each order of Pseudo-Zernike moments. According to the principle of amplitude rotation invariance, the parameters of
subpixel edge can be obtained by analyzing the relationships between different orders and repetitions of Pseudo-Zernike
moments when the image edge is rotated to the vertical direction. And then the actual coordination of the subpixel edge
point can be identified. Comparing with other approaches such as spatial moment operators, and Zernike moment
algorithm, the experiment results prove that the proposed method has the virtue of higher measuring precision and better
noise suppression performance. The edge detection accuracy is up to 0.07 pixel for straight lines with noise, and 0.1 pixel
for curves with noise. Therefore, it can be concluded that the proposed method is an efficient approach with a relatively
high accuracy and stabilization for image edge detection.
Study on height calibration in the PMP measurement system
Ya-feng Zhang,
Hua-zhi Wu,
Xuetao Pan,
et al.
Show abstract
Phase modulated object height information is get by phase shift technology or Fourier transformation technology in the
PMP measurement system, and then get continuous phase by phase demodulation and phase unwrapping technology, and
get object height information based on system height formula. In theory, telecentric beam path projector lens center and
CCD incidence diaphragm center are located in the common vertical plane, and their light axis are located in the
common horizontal plane, and then exact system parameters are get. But it is impossible to come true this demand in
fact. So in this paper, calibrate object height and optimize structure parameters in a general system by the least square
interactive method and genetic algorithm, in which selected real-coded Genetic algorithm, right population size, adaptive
fitness function, crossover operator and mutation operator, and then realized spatial identification. Compared with the
traditional least square interactive method, experimental results show that this method has better calibration precision
and improves the 3-D measure precision of the system.
Effects of different nanostructural ZnS films on the characteristics of organic/inorganic heterostructure devices
Show abstract
Organic/inorganic heterostructure ITO/poly[2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylene vinylene] (MEHPPV)/
ZnS/Al devices were fabricated. The effects of different nanostructural ZnS thin films on the characteristics of the
devices were studied in detail. Different nanostructural ZnS thin films were prepared by glancing angle deposition
(GLAD) technology. ZnS films were deposited on pieces of indium tin oxide (ITO) substrates coated with MEH-PPV in
an electron beam evaporation system when the oblique angle was set to 0° and 80° respectively. During the deposition
process, the base pressure of vacuum chamber was 3×10-4 Pa, the deposition rate was fixed at 0.2 nm/s and the rotation
rate of the substrate was 0.05 rev/s. Scanning electron microscope (SEM) images show that ZnS nanocrystalline films
were formed on the substrates at different oblique angles, but the nanocolumnar structure was only formed at the
situation of α=80°, and a continuous and uniform ZnS thin film was obtained at 0°. The electroluminescence (EL)
intensities of the organic/inorganic heterostructure devices were enhanced compared with the single-layer devices, and
the device with the nanocolumnar ZnS layer showed higher emission intensity compared with the one composed by the
continuous ZnS film deposited at normal incidence under the same driving voltage. The different nanostructural ZnS
films were found to have direct effects on the electrical and luminance characteristics of the organic/inorganic
heterostructure devices.
Au-coated MCP photo-detector and its energy spectrum response
Show abstract
Micro-channel Plate (MCP), which can be served as electron multiplier achieved by the surface of micro-pores that has
some electrical conductivity and performs well in producing secondary electrons, is a fiberglass plate made of silicate
glass containing oxide of lead, bismuth and otherwise. Once coated with cathode film both sides, MCP is capable of
responding to ultraviolet (UV) of several eV and x-ray of several keV. When gold is applied as photocathode, it has good
stability of emission, photoelectric emission character would not be changed even though exposed in the air several
times, and the photoelectric current density distributes uniformly. This article introduces a special photo-detector, which
employs MCP as dielectric substrate, and evaporates a layer of thin Au on the front surface acted as the photocathode
and input electrode, while a layer of general electrode on the back surface. In addition, an electron receiver is also needed
to structure the photo-detector. Energy spectrum response at ultraviolet band of this Au coated MCP photo-detector was
measured through measuring the response current of the detector between 200~340 nm (3.66~6.22 eV) directly. The
selective photoemission of Au has been found, which had been found only for alkali metals.
Organic light-emitting diodes based on bipolar material FLAMB-1T
Show abstract
Organic light-emitting diodes (OLEDs) were fabricated with a structure of indium-tin-oxide (ITO)/poly(Nvinylcarbazole)
(PVK): 2-{4-[bis(9,9-dimethylfluorenyl)amino]phenyl}-5-(dimesitylboryl)thiophene (FLAMB-1T)/[tris
(8-quinolinolato) aluminum (Alq3) or 2,2',2"(1,3,5-benzenetriyl) tris-(1- phenyl-1Hbenzimidazole) (TPBi)]/Mg : Ag by
spin coating method using a bipolar material of FLAMB-1T. Electroluminescent (EL) spectra characteristic was
investigated, and the performance differences of the OLEDs were analyzed. Also, the luminance-voltage characteristics
of the two devices were compared. The luminances of the devices were 2085 and 4389 cd/m2 at 15.5 V. The maximum
power efficiencies of the devices were 0.24 and 4.9 lm/W. The EL spectra were located at 520 and 478 nm with the
electron transporting layer of Alq3 and TPBi, respectively. The emitting processes of the device were discussed using
energy transfer and direct carrier trapping principle in polymeric material.
Effect of corona poling on structure evolutions of alpha-phase and beta-phase PVDF films
Show abstract
In this work, Static piezoelectric measuring tester was used to examine piezoelectric strain constant variations as
function of corona fields; it also introduced XRD experiments were carried out on PVDF films with different corona
voltage. Such information may be relevant in identifying changes in the degree of crystallinity and crystalline phase
changes that occur during poling process. Complementary information was also obtained by performing differential
scanning calorimetry (DSC) studies of the same samples. The results show that the poled films exhibit better
piezoelectric properties than non-poled ones due to structural changes during corona poling process. A decrease in the
degree of crystallinity is found and better piezoelectric characteristics can be obtained in poled β-phase films. However,
the value of piezoelectric strain constant of poled α-phase films was relative lower in comparison with β-phase ones due
to existence of a considerable number of non-polar phase content in crystalline region.
Study on the detectivity of the pulsed infrared thermograph
Show abstract
Infrared thermography as a wide-area, rapid, and noncontact nondestructive testing (NDT) method has been widely
recognized for many years. It is based on the thermal wave theory, using different heat source to heat the detected
samples, Pulsed Infrared Thermography has emerged as the most widely used form of the technique, through the
measurement of the surface temperature, the inside information of the sample can be obtained. However, the detectivity
of the Pulsed Infrared Thermography has its limitations, fundamental detectivity of a flaw will depend on its size, depth
and the distance between two adjacent flaws. In this paper, the theoretical analysis of detectivity of infrared pulsed
thermography and criteria to assess the detectivity are discussed , as well as the theoretical testing limit is given for the
Pulsed Infrared Thermography , two related experiments are done, one sample is the aluminum plate with back-drilled
rectangle flumes, having six flumes in the same size but different depths, the sample is used as the detectivity reference
sample, which is used to analysis the relationship between detectivity of the pulsed infrared system and the characters of
a flaw. Meanwhile, a second sample is the Sandwiched structures which are composed by a honeycomb core between
two multi-layer carbon fiber reinforced plastic (CFRP) facesheets, the structure is widely used in aerospace nowadays, it
has flaws in different sizes, depths and distances between two flaws, the second sample is used to study the influence
factors of the detectivity of the Pulsed Infrared Thermography. For the CFRP sample, the detectable size, depth, and
distances between the flaws are given as a result. From the two different experiments, detectivity of the Infrared Pulsed
Thermograhy has been studied.
CMOS image sensor with contour enhancement
Liya Meng,
Xiaofeng Lai,
Kun Chen,
et al.
Show abstract
Imitating the signal acquisition and processing of vertebrate retina, a CMOS image sensor with bionic pre-processing
circuit is designed. Integration of signal-process circuit on-chip can reduce the requirement of bandwidth and precision
of the subsequent interface circuit, and simplify the design of the computer-vision system. This signal pre-processing
circuit consists of adaptive photoreceptor, spatial filtering resistive network and Op-Amp calculation circuit. The
adaptive photoreceptor unit with a dynamic range of approximately 100 dB has a good self-adaptability for the transient
changes in light intensity instead of intensity level itself. Spatial low-pass filtering resistive network used to mimic the
function of horizontal cell, is composed of the horizontal resistor (HRES) circuit and OTA (Operational
Transconductance Amplifier) circuit. HRES circuit, imitating dendrite of the neuron cell, comprises of two series MOS
transistors operated in weak inversion region. Appending two diode-connected n-channel transistors to a simple transconductance
amplifier forms the OTA Op-Amp circuit, which provides stable bias voltage for the gate of MOS
transistors in HRES circuit, while serves as an OTA voltage follower to provide input voltage for the network nodes. The
Op-Amp calculation circuit with a simple two-stage Op-Amp achieves the image contour enhancing. By adjusting the
bias voltage of the resistive network, the smoothing effect can be tuned to change the effect of image's contour
enhancement. Simulations of cell circuit and 16×16 2D circuit array are implemented using CSMC 0.5μm DPTM
CMOS process.
CFRP sandwiched facesheets inspected by pulsed thermography
Huijuan Li,
Yan Huo,
Liangxu Cai,
et al.
Show abstract
Carbon fiber reinforced polymer (CFRP) has been always used in aerospace, Sandwiched structures composed by a
honeycomb core between two multi-layer CFRP facesheets are very common on aerospace parts. As to the application of
the CFRP sandwiched facesheets is extended, The demand for quality control of CFRP sandwiched composites is
increasing, Infrared thermography is one of several non-destructive testing techniques which can be used for defect
detection in aircraft materials such as carbon-fibre-reinforced composites. Infrared thermography can be potentially
useful, as it is quick, real time, non-contact and can examine over a relatively large area in one inspection procedure. The
technique is based on heating the sample surface with different heat sources and monitoring the surface temperature of
the sample with an IR camera, any abnormal behavior of the surface temperature distribution indicates the subsurface
defect. This kind of structure is normally affected by anomalies such as delaminations, disbonding, water ingressing to
the core. in this paper, several different kinds of defects which are of various size and depth below the test surface are
planted in the CFRP composites, the Teflon inserts between the plies in the facesheet represents the delaminations, the
Teflon inserts between the inner facesheet and adhensive or between adhensive and core are simulated disbonding in the
composites, they are all tested by pulsed thermography, meanwhile, these samples are also inspected by ultrasonic
testing, compare with each characteristic and the results got by these two different methods, it shows that pulsed
thermography is an effective nondestructive technique for inspecting CFRP composites.
Design of the data acquisition and real-time imaging system for UIRFPA
Show abstract
This paper presents a useful design of the time-series driving, data acquisition and real-time imaging system for the
uncooled infrared focal plane arrays (UIRFPA). The field programmable gate array (FPGA) is used as the central
processing unit (CPU) in the system, which can control and harmonize all functional modules. The Ping-Pong structure
is employed to realize real-time imaging. The SDRAM is adopted for the data storage to fulfill the need of mass
memory. And there are also some switches and keys to provide human-machine interaction. This system works for
UIRFPA with resolution of 320×240 steadily and authoritatively. The noise doesn't merge in main signals, so the system
can extract the signals of UIRFPA accurately and efficiently.
Modeling of image matching accuracy with image metrics based on least squares matching algorithm
Show abstract
The determination of conjugate points in a stereo image pair, i.e. image matching, is the critical step to realize automatic
surveying and recognition in digital photogrammetric processing. The accuracy of image matching is closely related to
specific matching algorithm as well as images. In this paper, the qualitative and quantitative relationships between the
matching accuracy and the image metrics are studied at the basic of Least Squares Image Matching algorithm (LSIMA).
Firstly, the algorithm is deduced mathematically, and then the main image metrics affecting the matching accuracy are
presented, including total variation (TV) metric and difference of signal-to-noise ratio (DSNR) metric. Subsequently,
variations of matching accuracy with TV and DSNR are analyzed, and mathematical model between them is developed.
Studies show that the matching accuracy presents the natural exponential rule along with TV and DSNR of image pairs.
Besides, parameters of the model are estimated and the model is verified by simulation experiments. Finally, the
correctness of the model is verified using real remote sensing images. Experimental results demonstrate the robustness
and accuracy of the proposed model.
Based on airborne multi-array butting for IRFPA staring imagery
Show abstract
Because infrared system detects the radiation energy of the target, it has the ability to work all day that the visible-light
detection system cannot achieve, at the same time, infrared system is a passive detection system, does not need active
detection technology such as radar, which requires large radiation power or a larger expandable antenna. It is more
suitable for airborne applications, therefore, infrared imaging based on the aircraft and aerostat platform, has been an
important means of monitoring the ground. However, due to detector limitations, the spatial resolution of current infrared
cameras or spectrographs and the total field coverage of view are generally not satisfied the customer's requirements.
This paper proposes an airborne infrared camera imaging method based on multi-planar arrays, using frame-type
imaging array. In order to provide large ground coverage together with good spatial resolution, the mirror is drove to
scan rapidly by the galvanometer. The scanning mirror works at staring imagery mode. During multi-planar detectors
exposure and imaging, the mirror moves to the staring position. There is more than 10 % overlapping sensor foot prints
between two adjacent frames, and the functions of image matching algorithms are used to ensure the seamless butting.
This imaging method improves the system integration time, and effectively improves the sensitivity of infrared systems;
frame-type imaging solves the serious image distortion caused by the platform attitude.
The design of the high-power semiconductor laser signal transmitter
Na Shen,
Xianjing Zhang,
Nengdong Wang
Show abstract
The paper mainly focuses on the research of the high-power semiconductor laser signal transmitter. There are two keys
in the design: first, the power-driven technology of the high-power semiconductor laser. The paper generates fast current
pulse in a low-impedance load by the way of control the pulse length to drive the semiconductor lasers. Second, the
information coding techniques based on laser pulses. It is realized in the control of Field-Programmable Gate Array. In
additionally, in the optical window design, the system use of inverted telescope lens structure to compress and collimate
the laser beam. The specimen achieved the desired performance in experiment.
Study on optical properties of two-color microbolometers
Show abstract
In this article, the practical structure of two-color microbolometers for uncooled infrared detection was considered, a
mathematical model to calculate infrared absorptance was described. The optical characteristic of multilayer structure
consisting of Nitride (SiNx) infrared absorber film/ Vanadium (VOx) heat sensitive film/ SiNx support film/ the first
optical resonant cavity/ a tunable reflecting Al micromirror/ the second optical resonant cavity /a bottom electrode made
up of Al was investigated. According to optical admittance matrix theory, relation between infrared absorber film
thickness, the first optical resonant cavity of two-color microbolometer and infrared absorptivity was simulated by
MATLAB software.
Fast-camera calibration of stereo vision system using BP neural networks
Show abstract
In position measurements by far-range photogrammetry, the scale between object and image has to be calibrated. It
means to get the parameters of the perspective projection matrix. Because the image sensor of fast-camera is CMOS,
there are many uncertain distortion factors. It is hard to describe the scale between object and image for the traditional
calibration based on the mathematical model. In this paper, a new method for calibrating stereo vision systems with
neural networks is described. A linear method is used for 3D position estimation and its error is corrected by neural
networks. Compared with DLT (Direct Linear Transformation) and direct mapping by neural networks, the accuracy is
improved. We have used this method in the drop point measurement of an object in high speed successfully.
Spectrum acquisition of detonation based on CMOS
Show abstract
The detection of high-speed dynamic spectrum is the main method to acquire transient information. In order to obtain the
large amount spectral data in real-time during the process of detonation, a CMOS-based system with high-speed
spectrum data acquisition is designed. The hardware platform of the system is based on FPGA, and the unique
characteristic of CMOS image sensors in the rolling shutter model is used simultaneously. Using FPGA as the master
control chip of the system, not only provides the time sequence for CIS, but also controls the storage and transmission of
the spectral data. In the experiment of spectral data acquisition, the acquired information is transmitted to the host
computer through the CameraLink bus. The dynamic spectral curve is obtained after the subsequent processing. The
experimental results demonstrate that this system is feasible in the acquisition and storage of high-speed dynamic
spectrum information during the process of detonation.
Study on algorithm and real-time implementation of infrared image processing based on FPGA
Yulin Pang,
Ruijun Ding,
Shanshan Liu,
et al.
Show abstract
With the fast development of Infrared Focal Plane Arrays (IRFPA) detectors, high quality real-time image processing
becomes more important in infrared imaging system. Facing the demand of better visual effect and good performance,
we find FPGA is an ideal choice of hardware to realize image processing algorithm that fully taking advantage of its high
speed, high reliability and processing a great amount of data in parallel. In this paper, a new idea of dynamic linear
extension algorithm is introduced, which has the function of automatically finding the proper extension range. This
image enhancement algorithm is designed in Verilog HDL and realized on FPGA. It works on higher speed than serial
processing device like CPU and DSP. Experiment shows that this hardware unit of dynamic linear extension algorithm
enhances the visual effect of infrared image effectively.
Calculation of optical band gaps of a-Si:H thin films by ellipsometry and UV-Vis spectrophotometry
Show abstract
Hydrogenated amorphous silicon (a-Si:H) thin films doped with Phosphorus (P) and Nitrogen (N) were deposited by
radio frequency plasma enhanced chemical vapor deposition (RF-PECVD). The optical band gaps of the thin films
obtained through either changing the gas pressure (P-doped only) or adulterating nitrogen concentration (with fixed P
content) were investigated by means of Ellipsometric and Ultraviolet-Visible (UV-Vis) spectroscopy, respectively. Tauc
formula was used in calculating the optical band gaps of the thin films in both methods. The results show that
Ellipsometry and UV-Vis spectrophotometry can be applied in the research of the optical properties of a-Si:H thin films
experimentally. Both methods reflect the variation law of the optical band gaps caused by CVD process parameters, i.e.,
the optical band gap of the a-Si:H thin films is increased with the rise of the gas pressure or the nitrogen concentration
respectively. The difference in optical band gaps of the doped a-Si:H thin films calculated by Ellipsometry or UV-Vis
spectrophotometry are not so great that they both can be used to measure the optical band gaps of the thin films in
practical applications.
Research on infrared image enhancement algorithm based on histogram
Jie Zhang,
Ziji Liu,
Yanzhao Lei,
et al.
Show abstract
Infrared image often has the defects of low contrast and high dynamic range. Image enhancement technology is very
important for infrared images. In this paper, several methods were introduced to improve the quality of infrared images.
At first, images from IRFPA must be pre-processed by the algorithm of blind compensation and non-uniformity
correction (NUC). Then, the image was enhanced by the algorithm of direct gray scale transformation and plateau
equalization (PE). The quality of the image was enhanced effectively. However, the noise was also amplified. At last, the
image noise was suppressed by using median filter. The experiment result indicates that infrared image enhancement
algorithm can not only enhance image contrast effectively but also keep the detail information of original infrared image
well.
Design of SOPC-based infrared image enhancement system
Show abstract
On the basis of the brief introduction to theory of uncooled infrared thermal imaging system and the infrared image
processing algorithms, the key technologies to real-time image enhancement was studied, which driving a 160×120
Infrared Focal Plane Arrays (IRFPA) imaging system. In this article, an uncooled infrared thermal imaging system with
real-time image processing and image enhancement was designed and developed, most importantly, a better result was
achieved. Aiming at the Infrared Focal Plane Arrays (IRFPA), the hardware system used flexible design approach and
efficiently developed tools on System-on-a-Programmable-Chip(SOPC)with two SDRAMs memories used as frame
buffers. By this means, the 160 × 120 of IRFPA realized image acquisition. In this article, the structure of the system and
the software realization of infrared images to achievement of the non-uniformity correction and image enhancement
algorithm for parallel operation On the SOPC were described in details.The results showed that the design of SOPCbased
real-time infrared image processing system could simplify system hardware and software design while ensuring
the computing abilitiy. To the IRFPA imaging system of 160 × 120, processed infrared image quality was improved
significantly to meet the real-time dynamic detection and tracking needs. Finally a system of uncooled infrared thermal
imager with high price quality and convenient reconfiguration condition was implemented.
Simulation and analysis of ACB'S photometric signature based on STK
Show abstract
The basic theory of observations on ACBs' photometric signature is studied in this paper. A ground-based
opto-electrionic observation emulation method with STK and MATLAB is presented to solve the problem that the real
space observation is hardly run under the condition of technology institute. A spatial object brightness change model is
established in combination of blackbody radiation theory. The photometric characteristics of space object are then
analyzed using the above model by the simulation platform. Respectively, a low-orbit satellite and a tumbling rocket are
simulated. The desired results are achieved by analysing brightness changes of the targets on various operating.
980-nm 14-pin butterfly module dual-channel CW QW semiconductor laser for pumping
Show abstract
Nowadays, with its mature progress, the 790 nm - 1000 nm wavelength semiconductor laser is widely used in the fields
of laser machining, laser ranging, laser radar, laser imaging, laser anti-counterfeit, biomedical and etc. Best of all, the
980 nm wavelength laser has its widespread application in the pumping source of Er3+ -doped fiber amplifier, optic fiber
gyroscopes and other devices. The output wavelength of the fiber amplifier which takes the 980 nm wavelength laser as
its pumping source is between 1060 nm and 1550 nm. This type of laser has its extremely wide range of applications in
optical communication and other fields. Moreover, some new application domains keep constantly being developed. The
semiconductor laser with the dual-channel ridge wave guide and the 980 nm emission wavelength is presented in this
paper. In our work, we fabricated Lasers with the using of multi-quantum well (MQW) wafer grew by MBE, and the PL-wavelength
of the MQW was 970 nm. The standard photofabrication method and the inductively coupled plasma (ICP)
etching technology are adopted in the process of making dual-channel ridge wave guide with the width of 4 μm and
height of 830 nm. In the state of continuous work at room temperature, the laser could output the single mode beam of 70
mW stably under the current of 100 mA. The threshold current of the laser diode is 17 mA and the slope efficiency is
0.89 W/A. The 3 dB spectrum bandwidth of the laser beam is 0.2 nm. This laser outputs its beam by a pigtail fiber on
which Bragg grating for frequency stabilization is carved. The laser diode, the tail fiber, and the built-in refrigeration and
monitoring modules are sealed in a 14-pin butterfly packaging. It can be used directly as the pumping source of Er3+ -
doped fiber amplifier or optic fiber gyroscopes.
Underwater object detection technology based on polarization image fusion
Yongguo Li,
Shiming Wang
Show abstract
The performance of the traditional underwater optical imaging systems is ultimately limited by the absorption and
scattering properties of the water substance. Polarimetric imaging can be used to remove degradation effects, and can be
applied to high-level vision tasks, such as object classification and recognition and camouflage identification, etc. The
method of improving contrast was presented by polarization imaging. The polarization images when the angle of
polarization are 0°, 45°, 90° and 135°, the gray levels of the images are calculated by program. There are much
complementary and redundancy information among the polarization images. According to the character of parameter I of
stokes vector, degree of linear polarization (DoLP) and the angle of polarization (AoP), A RGB false color based
polarimetric images fusion are given to enhance the contrast.
X-ray integrated digital imaging system based on a-si flat panel detector
Jian Fu,
Bin Li,
Baihong Jiang
Show abstract
X-ray phase contrast imaging (X-PCI) is one of the novel imaging methods. For the low density substance, it provides
better images than the conventional X-ray attenuation imaging. In order to get a high-quality image, X-PCI adopts the
high spatial resolution image intensifier as the detector. However, the X-ray attenuation imaging usually adopts the high
sensitivity a-si flat panel detector (FPD) as the detector. So it is currently one of the questions in the field of X-ray
imaging how to realize these two functions at a system: X-ray attenuation imaging and X-PCI. An X-ray integrated
digital imaging system based on FPD is designed and developed after analyzing the imaging principle of X-PCI and the
imaging feature of FPD. The results from simulation and experiments in this system show that the X-PCI image can be
acquired without affecting the quality of the conventional X-ray attenuation image. It demonstrates the possibility to
realize these two functions at a system.
Application of stimulated rotational Raman scattering technique in NO2-DIAL system
Dawei Fang,
Ben Xu,
Kai Yang,
et al.
Show abstract
Differential Absorption Lidar (DIAL) for detecting atmospheric pollution is used extensively for its high precision and
spatial resolution. The selection of the suitable absorption wavelength and the stimulation and modulation of the
corresponding laser source are of key importance for DIAL system. This literature presents first a new approach for
attaining the specific absorption wavelength in design of the new type NO2-DIAL. The third harmonic of Nd:YAG laser
itself is taken as the selected λon (354.7 nm), and is converted to the circularly or elliptically polarized laser to pump the D2 Raman cell, acquiring plentiful frequency spectrum of stimulated vibrational and rotational Raman scattering light, among which the first-order pure stimulated rotational Raman scattering light nearest to the pumping laser wavelength is
taken as the λoff (359.9 nm) for DIAL. The polarization state of the pumping laser can be conveniently modulated by using a λ/4 wave-plate. It is of large advantages in raising the technical performance and the economical efficiency. The technique will be very useful for DIAL to detect other constituents of atmospheric pollution.
Research on detection characteristics test method for infrared detector in low temperature background
Shitao Wang,
Wei Zhang,
Qiang Wang
Show abstract
In research fields such as infrared astronomical observation and space fragments distribution analysis etc, the first and
possibly the most critical evaluation parameter of interest is detection sensitivity. Without adequate detection sensitivity,
it is impossible for infrared detector to detect the target at a distance great enough and play the role of terminal detector
of background. Although cryogenic optical system can be employed for the aim of increasing detection sensitivity up to
the possible maximum extent, research on detection characteristics test method for infrared detector in low temperature
background must be undertaken primarily before the cryogenic optical system is designed and manufactured. In this
paper, some of the fundamentals of detection characteristics test method are presented, and a set of experimental
apparatus is designed and established. Based on this apparatus and by employing an extend plane source blackbody, the
general rule of detection characteristics of infrared detector from normal temperature background to low temperature
background are investigated. The voltage-output signals of every pixel are continuously acquisitioned for F (≥100)
frames under two different blackbody temperatures, and as a result we obtain the evolving regularity of different
performance index, e.g. limiting integration time and detectivity D*. The measurement results reported in the paper
confirm that the integration time can be improved by a large margin in comparison with normal temperature background,
and the specific detecivity D* has the same variation tendency, which can be increased up to one order of magnitude.
Iterative blind image restoration with ringing reduction
Ju-feng Zhao,
Hua-jun Feng,
Zhi-hai Xu,
et al.
Show abstract
Image restoration is one of the most important problems in image processing. It is extremely difficult to obtain the
accurate PSF (Point Spread Function) of the degraded image captured from imaging system, so the method of iterative
blind deconvolution which is superior to the other ones is adopted. In blind image restoration, the estimation of initial
PSF plays a significant role. Meanwhile, with the increase of the number of iteration, ringing ripples may appear at
boundary and the regions where gray values vary severely, which affects the quality of the restored image. Therefore,
estimation of initial PSF and ringing reduction are two primary problems in blind iterative image deconvolution. A novel
approach combined the estimation of initial PSF with ringing suppression in blind iterative restoration is proposed. First,
a sophisticated variational Bayesian inference algorithm with natural image statistics is used to estimate initial PSF.
Cyclic boundary method is applied to suppress the ringing artifact at the boundary. As to the ringing in areas near edges,
spatial weighted matrix is adopted, because spatial weighted matrix can impose an adaptive local constraint on
restoration and smoothing to achieve better results. Finally, image quality assessment is used to evaluate the restored
image, which also could agree with human visual system. Experiments of simulation and real images show that this
approach can restore boundary and edge areas well and reduce the noise in smooth regions, which means that this
method can suppress ringing ripples and preserve more details validly.
Monte Carlo simulation of detecting space debris with lidar
Shengliang Fang,
Yuhua Fu,
Zhen Li
Show abstract
On the basis of analysis and processing of space background radiation, the article gives the detection probability when
the lidar detecting space debris, and compare the random variable which is produced by Monte Carlo method with the
detection probability, then get the detection results. The results reveal that, the detection model can well reflect the
impact of the random variable such as characteristics of the noise fluctuations in the detection process.
Nondestructive testing of rocket engine injector panel using ultrasonic burst phase thermography
Show abstract
As the key parts of the liquid rocket oxyhydrogen engine, the injector panel is a kind of transpiration material, which is
braided and Sintered with stainless steel wire. If some hidden delaminition defects that are difficult to detect appear in
the process of Sintering and rolling, a significant safety problem would occur. In this paper, we use the Ultrasonic Burst
Phase Thermography (UBP) to detect the delamination defects in the injector panel, UBP is a rapid and reliable
nondestructive technique derived from Ultrasonic Lock-in Thermography(ULT). It uses a controllable, adjustable
ultrasonic burst as the heat source to stimulate the sample, the defects within the material are revealed through their heat
generation caused by friction, clapping and thermoelastic effect, as the resulting surface temperature distribution is
observed by an infrared camera. The original thermal images sequence is processed by Fast Fourier Transformation to
obtain the phase information of the defects. In the experiments of the delamination sample, the UBP realized the
selective heating of delamination defects in the injector panel, and the signal to noise of phase image is higher than the
original thermal image because the phase information can not be disturbed by the initial conditions (such as the reflective
surface of sample). However, the result of the detection of flat bottom hole transpiration panel sample reflects that UBP
is not appropriate for the detection of this kind of defects, because it is difficult to induce frictional heating of flat bottom
holes. As contrast, Flash Pulse Thermography is used to detect the flat bottom holes, all of the holes of different depth
and sizes can be seen distinctly. The results show that PT is more appropriate for the detection of flat bottom holes
defects than UBP, therefore, it is important to select the appropriate excitation method according to different defects.
High-speed motion-blurred image restoration based on blind deconvolution
Lixin Liu,
Rong Xu,
Ganhua Li,
et al.
Show abstract
Due to camera vibration, target motion, atmospheric turbulence and the other factors, the received image is degraded
severely in the process of tracking and measurement of high-speed flight aircraft in the atmosphere. Aiming at this
problem, optimization of blurred image restoration is proposed based on a blind deconvolution restoration method. This
method estimates the direction of point spread function (PSF) in the frequency domain at first, and then estimates the
size of PSF by autocorrelation, and finally restores the degraded image by iteration on the appropriate constraint and
convergence conditions. The analysis of experimental results show that the method could reduce the phenomenon of the
image blur and ringing caused by the uncertainty site of PSF in the process of blind deconvolution and make the system
of measurement more precisely and effectively.
A hyperspectral images compression algorithm based on 3D bit plane transform
Lei Zhang,
Libin Xiang,
Sam Zhang,
et al.
Show abstract
According the analyses of the hyper-spectral images, a new compression algorithm based on 3-D bit plane transform is
proposed. The spectral coefficient is higher than the spatial. The algorithm is proposed to overcome the shortcoming of
1-D bit plane transform for it can only reduce the correlation when the neighboring pixels have similar values. The
algorithm calculates the horizontal, vertical and spectral bit plane transform sequentially. As the spectral bit plane
transform, the algorithm can be easily realized by hardware. In addition, because the calculation and encoding of the
transform matrix of each bit are independent, the algorithm can be realized by parallel computing model, which can
improve the calculation efficiency and save the processing time greatly. The experimental results show that the proposed
algorithm achieves improved compression performance. With a certain compression ratios, the algorithm satisfies
requirements of hyper-spectral images compression system, by efficiently reducing the cost of computation and memory
usage.
Dim-small-targets detection based on higher-order cumulant and wavelet method
Show abstract
A novel two-dimensional (2-D) adaptive filtering algorithm to enhance 2-D signals of small spatial extent embedded in
white Gaussian noise and a variety of outstanding modern digital signal processing methods are combined in background
segmentation. The coefficients of the adaptive filter converge to a special 2-D slice of the fourth-order cumulant function
of the input signal. The proposed algorithm is called the 2-D cumulant adaptive enhancer (2DCAE). And the methods in
background segmentation is combining the wavelet energy transformation, data integration and threshold segmentation.
High-speed SPGD wavefront controller for an adaptive optics system without wavefront sensor
Show abstract
A non-conventional adaptive optics system based on direct system performance metric optimization is illustrated. The
system does not require wave-front sensor which is difficult to work under the poor condition such as beam cleanup for
the anomalous light beam. The system comprises a high speed wavefront controller based on Stochastic Parallel Gradient
Descent (SPGD) Algorithm, a deformable mirror, a tip/tilt mirror and a far-field system performance metric sensor. The
architecture of the wave-front controller is based on a combination of Field Programmable Gate Array (FPGA) and
floating-point Digital Signal Processor (DSP). The Zernike coefficient information is applied to improve the iteration
speed. The experimental results show that the beam cleanup system based on SPGD keep a high iteration speed. The
controller can compensate the wavefront aberration and tilt excursion effectively.
Joint transform correlator based on CIELAB model with encoding technique for color pattern recognition
Show abstract
The CIELAB standard color vision model instead of the traditional RGB color model is utilized for polychromatic
pattern recognition. The image encoding technique is introduced. The joint transform correlator is set to be the optical
configuration. To achieve the distortion invariance in discrimination processes, we have used the minimum average
correlation energy approach to yield sharp correlation peak. From the numerical results, it is found that the recognition
ability based on CIELAB color specification system is accepted.
Study the encountering simulation system for laser fuze based on intensity attenuation and fiber delay
Show abstract
Laser fuze is a kind of proximity fuze developed with laser technology. A encountering simulation system for laser fuze
based on environment simulator and fiber retarder is introduced in this paper. The system can simulate the process for
the laser fuze to approach the target quickly, with consideration of changing light path and intensity caused by factors
like environment and distance. It can be a reference for the future design of laser fuze.
The energy coupling between two chiral waveguides
Jiaqun Zhao,
Ping Cheng,
Junqing Li
Show abstract
We discuss the coupling properties in isotropic chiral waveguides. By using Lorentz reciprocity theorem, we obtain a set
of coupled linear equations for left- and right-circularly components in isotropic chiral waveguides. From the equations,
the light propagation properties in chiral waveguides are obtained. The numerical results show that all the energy in one
chiral waveguide can be completely converted into another at special position in coupling region. The energy coupling
between two chiral waveguides can be use to design novel optical devices.
Wave-shaping and engineering realization of CCD driving signals
Yan Wang,
Tao Li
Show abstract
High-speed driving signals will easily incur the substrate bounce of CCD(charge-coupled device), causing the charge
transfer of CCD, which not only reduces the charge transfer efficiency but also produces dispersion. Thus the CCD
imaging quality will be severely influenced. This paper introduces the classification and work principle of driving signals
and elaborates the mechanism of the occurrence of the substrate bounce of CCD. Taking the characteristics of high speed
driving signals into consideration, the paper provides a method to restrict the substrate bounce's disturbance to CCD
signals based on the driving signal wave-shaping theory. Theoretically speaking, the driving signal wave-shaping theory
may effectively restrict the substrate bounce of CCD. Moreover, the circuit simulation proves the correctness of the
theory. After the wave-shaping process to CCD driving circuits, the test results of CCD signals obviously excel those
without wave-shaping. The circuit test also shows that the substrate bounce's disturbance to CCD signals is effectively
restricted. The test proves the feasibility of the engineering about wave-shaping, providing a scientific theory for the
focal plane high-speed driving circuit design in the future.
Timing generator of scientific grade CCD camera and its implementation based on FPGA technology
Guoliang Si,
Yunfei Li,
Yongfei Guo
Show abstract
The Timing Generator's functions of Scientific Grade CCD Camera is briefly presented: it generates various kinds of
impulse sequence for the TDI-CCD, video processor and imaging data output, acting as the synchronous coordinator for
time in the CCD imaging unit. The IL-E2TDI-CCD sensor produced by DALSA Co.Ltd. use in the Scientific Grade
CCD Camera. Driving schedules of IL-E2 TDI-CCD sensor has been examined in detail, the timing generator has been
designed for Scientific Grade CCD Camera. FPGA is chosen as the hardware design platform, schedule generator is
described with VHDL. The designed generator has been successfully fulfilled function simulation with EDA software
and fitted into XC2VP20-FF1152 (a kind of FPGA products made by XILINX). The experiments indicate that the new
method improves the integrated level of the system. The Scientific Grade CCD camera system's high reliability, stability
and low power supply are achieved. At the same time, the period of design and experiment is sharply shorted.
128×128 dual-color ROIC with electrical crosstalk resistant design
Show abstract
Dual-color(MWIR/SWIR)infrared focal plane array with sequence integration mode. It can export two bands
photocurrent signal under irradiation. In order to deal with the signal electrical crosstalk problem which the unstable
and large variant bias voltage of N-P+-N HgCdTe infrared detectors bring while two bands switch, A novel
modified DI (MDI)circuit structure based on adjusting the bias voltage is presented. Through controlling timing
sequence, MWIR and SWIR signal are integrated in turn and readout at the same time. The chips of 128×128 ROIC
are designed and fabricated with 0.6 um double poly double metal mixed signal technology. The simulation shows
right function of the circuit. Power dissipation of analog module is 20 mW, that of digital module is 10.25 uW and it
has been tapped out.
A CMOS transimpedance amplifier for pulsed laser range finder
Show abstract
The pulsed laser range finding has been extensively applied in space exploration, military use and industry, due to its
advantages over other methods of non-contact ranging in simplicity, non-cooperativeness of objects, long detecting range
and short range acquisition time. The integration of its receiver channel will be beneficial to weight-lightening,
miniaturization and mass production of the laser range finder. A transimpedance amplifier for receiver channel of pulsed
range finder is designed using 0.6-μm CMOS technology in this work. It consists of transimpedance pre-amplifier, R-2R
resistors ladder variable attenuator and post-amplifier. A regulated cascade circuit (RGC) is used to isolate the input
capacitor from input node of transimpedance pre-amplifier, reducing the bandwidth suppression caused by large input
capacitor. R-2R variable attenuator is implemented for digital gain control, achieving a total gain control range of 42dB
with 7 steps and 6dB per step. Simulation shows that the circuit achieves a bandwidth of 83 MHz with the presence of a
5-pF input capacitor, and a maximum transimpedance of 125.5dBΩ, meeting the requirement of high-precision pulsed
laser range finder.