Direct diamond turning of steel molds for optical replication
Author(s):
Fritz Klocke;
Olaf Dambon;
Benjamin Bulla;
Michael Heselhaus
Show Abstract
In this paper the most recent investigations in ultrasonic assisted diamond machining of hardened steel at the Fraunhofer
IPT is presented. The goal of this technology is to unify the outrageous specifications of diamond machining process
with steel material. The focus lies on the kinematic influence of the discrete frequencies 40 kHz and 60 kHz. Special
interest is given to the reachable surface roughness depending on process parameters. The machined steel (1.2083,
X40Cr14, STAVAX ESU) is a common mold die material for optical replication processes.Results of the accomplished
investigations show the potential of the ultrasonic assisted process and recent developments. By increasing the frequency
from 40 kHz to 60 kHz the overall process stability is increased. This makes the process less vulnerable towards feed rate
variation or towards the variation of machined material hardness. Furthermore no tool wear is detected at high material
removal rates or high cutting distances during component machining.
Double-swing method used for polishing off-axis aspherical mirrors
Author(s):
Peng Wang;
Jun-feng Li;
Bin Xuan;
Xiao-ping Chen;
Shu-mei Song;
Ya Chen;
Jing-jiang Xie
Show Abstract
Based on the characteristics of off-axis aspherical surface, a new method used for polishing off-axis aspherical
mirrors-Double-Swing Method (DSM) is proposed in this paper, and the polishing mechanism of DSM is introduced.
The mathematical model of the DSM with steady movement state is established. The movement of this mathematical
model is simulated in a programming language; the comparison of simulation effects under different parameters is made.
In order to achieve optimal parameters, a high order off-axis rectangle aspherical mirror has been polished by DSM. The
final result of profile measurements of 12nm, RMS is achieved. The result indicates that the method is of practice and
has even higher working efficiency and precision.
A mechanistic cutting force model for diamond fly-cutting of microstructured surface
Author(s):
Qingliang Zhao;
Bing Guo;
Hui Yang;
Xiaohu Zhang
Show Abstract
In diamond fly-cutting of microstructured surface, the cutting force plays a crucial role in the establishment of cutting
plans, the setting of cutting conditions and the determination of the characteristics of cutting processes like tool wear
and surface texture. The characteristics of cutting force are introduced and a mechanistic cutting force model for
predicting the cutting force in diamond fly-cutting of microstructured surface is proposed in this study. In the model the
cutting edge radius of single crystal diamond tool is considered. Furthermore the contribution of elastic deformation of
the workpiese to the total force is also accounted. The force components in the horizontal 'X' and 'Y' direction are
calculated from material hardness, elastic modulus, uncut chip area, tool geometry and the average value of shear angle
respectively. And the predicted cutting forces are consistent with experimental cutting force.
Precision compression molding process of low Tg glass aspheric lenses
Author(s):
Tao Ma;
Jingchi Yu
Show Abstract
Precision Glass Molding Process is adopted for mass production of aspheric lenses, micro-lens array, diffractive optical
elements and free-form lenses which are difficult to be manufactured by using conventional methods. In this research,
high order aspheric lenses with 6th item are molded using the glass material P-SK57 which is characterized by a low
glass transition temperature (Tg) 493°C and thermal expansion coefficient (TEC) 8.9×10-6. Some of the molding
conditions are as follow: 1) the molding temperature is 565°C, 2) the pressure force is kept at 4KN for 90 seconds and 3)
the lens is cooling at an annealing velocity of 1.5~2°C /s to a release temperature of 180°C. The total molding cycle time
is about 16 minutes. Molded aspheric lenses are measured with a Taylorsurf contact profilometer and a Zygo Newview
white-light interferometer. As a result, the shape accuracy of molded lenses is less than 0.5um (PV) and surface finish
quality is less than 2nm.
Fabrication of microglass lens mould by using ultraprecision microgrinding process
Author(s):
Shaohui Yin;
Kun Tang;
Yongjian Zhu;
Fengjun Chen;
Yufeng Fan;
Li Guo
Show Abstract
With the rapid development of information technology and electro-optical communication industry, various micro
optical lenses have been used widely. Especially, because of great advantages concerning life, stability and imaging
characteristics, the demand for glass lens is increasing the high-precision imaging. This paper studies on the
ultra-precision parallel grinding technique of micro glass lens mould and investigates the form error compensation
technique in grinding process. Grinding test of micro-lens mould with 10mm in diameter is conducted, and the surface
roughness of Ra 5.98nm, Rz 34.95nm and form accuracy of PV 113nm, RMS 23nm are obtained.
Polishing of silicon based advanced ceramics
Author(s):
Fritz Klocke;
Olaf Dambon;
Richard Zunke;
D. Waechter
Show Abstract
Silicon based advanced ceramics show advantages in comparison to other materials due to their extreme hardness, wear
and creep resistance, low density and low coefficient of thermal expansion. As a matter of course, machining requires
high efforts. In order to reach demanded low roughness for optical or tribological applications a defect free surface is
indispensable. In this paper, polishing of silicon nitride and silicon carbide is investigated. The objective is to elaborate
scientific understanding of the process interactions. Based on this knowledge, the optimization of removal rate, surface
quality and form accuracy can be realized. For this purpose, fundamental investigations of polishing silicon based
ceramics are undertaken and evaluated. Former scientific publications discuss removal mechanisms and wear behavior,
but the scientific insight is mainly based on investigations in grinding and lapping. The removal mechanisms in polishing
are not fully understood due to complexity of interactions. The role of, e.g., process parameters, slurry and abrasives, and
their influence on the output parameters is still uncertain. Extensive technological investigations demonstrate the
influence of the polishing system and the machining parameters on the stability and the reproducibility. It is shown that
the interactions between the advanced ceramics and the polishing systems is of great relevance. Depending on the kind
of slurry and polishing agent the material removal mechanisms differ. The observed effects can be explained by
dominating mechanical or chemo-mechanical removal mechanisms. Therefore, hypotheses to state adequate explanations
are presented and validated by advanced metrology devices, such as SEM, AFM and TEM.
Freeform turning lathe with direct drives and aerostatic bearing
Author(s):
Chao-liang Guan;
Yi-fan Dai;
Zi-qiang Yin;
Fan Yang
Show Abstract
More and more precision freeform parts are required by defense technology and national economy today and in the
future. The applications of freeform parts have traditionally conformed to the limitations imposed by practical limits on
high effective fabricating technology. Single point diamond turning is one of the important methods of machining
freeform surface parts. Generally speaking, optical freeform surfaces have complex geometrical surface shapes and
require ultra smooth surface (roughness down to 10nm) and high form accuracy (form accuracy down to several ten
nanometers). So, the ultra precision turning lathe must improve the motion accuracy, dynamic stiffness and bandwidth of
every axis. Direct drive technology combined with aerostatic bearing do not affect by frication and eliminate the
micro-backlash and creeping; reduce the number of transmission element, shorten the transmitted chains and be
propitious to improve dynamic stiffness and bandwidth. This paper presents a ultra precision diamond turning lathe with
linear motor and aerostatic guide drive system. Combined with the lathe a FTS (Fast Tool Servo) system driven by voice
coil actor is use to machining free form surface. The turning experiments show that this lathe can satisfy the requirement
of machine freeform surface.
Influence of slurry pH on material removal rate and surface roughness of super-precision polishing of LBO crystal
Author(s):
Jun Li;
Yongwei Zhu;
Dunwen Zuo;
Yong Zhu;
Chuangtian Chen
Show Abstract
LBO crystal with high quality surface, which must be defect-free and super smooth, is urgently needed because of its
applications in high energy laser system. Chemical mechanical polishing (CMP) is adopted to raise surface quality and
processing efficiency in super precision polishing of LBO crystal. The polyurethane pad and colloidal SiO2 slurry are
chosen and the polishing experiments are performed on Logitech PM5 Precision Lapping & Polishing Machine. The
slurry pH is changed and its influence on material removal rate (MRR) and surface roughness is studied. The polished
surface roughness is measured by using atomic force microscope. MRR is calculated through the difference of the crystal
thickness between before and after polishing by polishing time. In the pH range from 2 to 6, MRR of LBO crystal
increases with pH decreasing and there is an optimal pH for surface roughness. While in the pH range from 7 to 13,
MRR and surface roughness vibrate with pH. The maximal MRR reaches 758 nm/min when slurry pH is kept at 2 and
the best surface roughness reaches 0.197 nm RMS when it at 4.
Material removal rate based on edge effects in ultraprecision polishing process
Author(s):
Wei Yang;
YinBiao Guo;
Qiao Xu
Show Abstract
Based on the edge effects in the ultra precision polishing process, a revised skin model is used to predict material
removal rate (MRR) of circular wafer. With force equation and torque equation, in order to calculate the skin width and
the pressure distribution, a revised formula is given. According to Preston's equation, by using Math-Cad software, the
material removal rate (MRR) of circular wafer is simulated, and two factors which influence MRR are discussed.One is
the distance between the circular wafer center and the polishing tool center; the other is the ratio of the angular velocity
of circular wafer to the polishing tool angular velocity.
Finite element simulation and experimental research in cutting forces of KDP crystal
Author(s):
Jinghe Wang;
Qingxin Meng;
Hongxiang Wang;
Shen Dong;
Jian Guo
Show Abstract
With the application of finite element (FE) software, a finite element model is established to simulate the cutting
procedure for KDP crystals. Based on this model, the influential factors on cutting force of KDP crystal in ultra-precision
cutting is analyzed. The study shows that the cutting forces will enlarge with the increment of the depth of cut, but the
influence of depth of cut on the cutting force is more significant. The cutting force decreases as the cutting speed
increases. The surface roughness decreases as the negative rake increases in the same cutting condition. Super-smooth
surface of KDP crystal can be obtained when edge angle is negative rake angle. Finally, cutting experiments are carried
out to validate the FE simulated results.
Experimental investigation on the effect of abrasive grain size on the lapping uniformity of a sapphire wafer
Author(s):
Donghui Wen;
Zhiwei Wang;
Kehua Zhang
Show Abstract
Experiments are taken to investigate the effect of abrasive grain size on the lapping uniformity of sapphire wafer, macro
and micro surface profiles are measured and compared by contact and contactless measurement methods. For W14
carbide boron abrasive lapping process, rolling and extruding effects are the main material removal mechanism and
leaves high density micro-crack on the lapped sapphire surface. On the other hand, W3.5 carbide boron abrasive grain
performs a ductile cutting process for material remove process under the same operated parameters, only scratch on
sapphire surface can be viewed by AFM. Experimental results show that abrasive grain size has a great effect on the
surface integrity of the lapped sapphire, charging status of abrasive grain into the lapping plate and its effect on the
surface integrity should be considered when choosing the abrasive grain size for precision lapping process. Lapping
uniformity both for macro and micro level, roughness and flatness of sapphire wafer can be achieved by using W3.5
carbide boron abrasive grain and acceptable by pre-polishing process.
Study on the influence and disposal method of the micro-cracks of optical components
Author(s):
Xiao-ping Chen;
Bin Xuan;
Peng Wang;
Jun-feng Li;
Shu-mei Song;
Hong Zhang;
Jing-jiang Xie
Show Abstract
Micro-crack is one of the most effective factor to the intensity and service life of optical components. Owing to the
micro-crack on surface, actual strength of optical components is reduced severely, even less than ten-percent of its
theoretical strength. According to fracture mechanics, the mechanisms of the formation and propagation of micro-crack
and the growth theory of sub-critical micro-crack are discussed in the paper firstly. Based on practice, an on-line test
method disposing etching holes-the molecule-infiltrating method and the principles of acid-etching method disposing
micro-crack are described. Followed by the demolishing mechanism of abrasives and a more reasonable removal
redundancy of fine-grinding and polishing during ,optical production is given by using abrasives in different-size orderly.
Experimental investigation on polishing of ultrasmooth surface in nanoparticle colloid jet machining
Author(s):
Xiaozong Song;
Yong Zhang;
Feihu Zhang;
Dianrong Luan
Show Abstract
In this paper, a nanoparticle colloid jet machining system has been developed for shaping and polishing ultra smooth
surfaces of brittle materials. Nanoparticle colloid jet machining is an ultra smooth surface processing technique which
utilizes surface chemical reaction between work surface atoms and nanoparticles in alkaline colloid to remove the
uppermost surface atoms. The purpose of the paper is to investigate the surface removal mechanism and process of
optical glass in nanoparticle colloid jet machining. Removal experiments have been conducted to show the removal
process. A K9 glass sample with a regulated surface profile has been polished and flattened in nanoparticle colloid jet
machining. The roughness of the K9 glass surface has been reduced from 31.6 nm RMS to less than 1 nm RMS. Atomic
force microscopy (AFM) were used to observe the surface microscopic morphological characteristics of K9 glass sample
processed by nanoparticle colloid jet machining. The observation results show that the protuberant sites on the work
surface are preferentially removed in nanoparticle colloid jet machining. Power spectral density analyses have been done
to evaluate the performance of the nanoparticle colloid jet machining. The PSD curves show that the surface has been
flattened within spatial wavelength of 0.04~10 μm after nanoparticle colloid jet machining.
Optical design and optimization of zoom optics with diffractive optical element
Author(s):
Yi-Chin Fang;
Han-Ching Lin
Show Abstract
The optical design of 350X zoom lens with Diffractive Optical Element (DOE) is demonstrated at the proposal. This lens
is composed of front elements, a zoom motor group and a compensation group. The compensation group is specially
designed to meet the further step motors under the control of DSP chips. Besides, location of DOE will be determined by
HTGA (Hybrid Taguchi Genetic Algorism) for further elimination of chromatic aberration. The results show that
regardless of whether chromatic aberration is axial or longitudinal, issues concerning the optical lens's DOE location
could be determined and chromatic aberration could be significantly reduced.
Effects of velocity and pressure distributions on material removal rate in polishing process
Author(s):
Yaguo Li;
Jian Wang;
Qaio Xu;
Wei Yang;
Yinbiao Guo
Show Abstract
The distributions of velocity and pressure during polishing process are analyzed in this paper and the effects of which on
material removed/removal rate (MR/MRR) are discussed. Usually, polished wafer moves in planetary kinematics pattern,
and when the rotation rate of wafer is identical with that of polishing pad the velocity distribution is theoretically
uniform from the viewpoint of wafer-pad interface as a whole. On the other hand, when a load is applied to the top
surface of wafer pressure distribution is even in the interior of wafer while the pressure sharply increases at the wafer's
border, which will inevitably affect the non-uniformity (NU) of MR/MRR, and therefore we have to adjust other
parameters, such as rotation rate of pad (or wafer) or improve motion pattern of wafer with respect to polishing pad, to
optimize the NU.
Development of an ultraprecision three axis micromilling machine
Author(s):
Peng Zhang;
Bo Wang;
Yingchun Liang
Show Abstract
To meet the requirement for high efficiency machining of the ultra-precision, ultra-smooth micro structured optical
surface, an ultra-precision three axes micro milling machine was developed. The overall size of the machine is
600mm×500mm×700mm and all the strokes of three axes are 75mm. To overcome nonlinearity that always exists in
conventional servo mechanism driven by ball screw, permanent-magnet linear motor is used to directly drive the
aerostatic bearing slide. Linear encoder with 1.2 nm resolution was used as the feedback of position to buildup closed
loop control system. The open architected CNC system is composed of the high performance embedded PMAC motion
control card and standard industrial PC, and the control algorithm is based on "PID + velocity/acceleration feed forward
+ notch filter" strategy. Test results indicate that the positioning accuracy of all the three axes is less than ±0.25μm, and
the repetitive positioning accuracy is less than ±0.2μm. The machine is proved to achieve nanometer scale through step
response and sinusoidal signal track. The preparatory milling experiments with micro cemented carbide milling cutter
further proves the processing capacity.
Deterministic magnetorheological finishing of optical aspheric mirrors
Author(s):
Ci Song;
Yifan Dai;
Xiaoqiang Peng;
Shengyi Li;
Feng Shi
Show Abstract
A new method magnetorheological finishing (MRF) used for deterministical finishing of optical aspheric mirrors is
applied to overcome some disadvantages including low finishing efficiency, long iterative time and unstable convergence
in the process of conventional polishing. Based on the introduction of the basic principle of MRF, the key techniques to
implement deterministical MRF are also discussed. To demonstrate it, a 200 mm diameter K9 class concave asphere with
a vertex radius of 640mm was figured on MRF polish tool developed by ourselves. Through one process about two hours,
the surface accuracy peak-to-valley (PV) is improved from initial 0.216λ to final 0.179λ and root-mean-square
(RMS) is improved from 0.027λ to 0.017λ (λ = 0.6328um ). High-precision and high-efficiency convergence of
optical aspheric surface error shows that MRF is an advanced optical manufacturing method that owns high convergence
ratio of surface figure, high precision of optical surfacing, stabile and controllable finishing process. Therefore, utilizing
MRF to finish optical aspheric mirrors determinately is credible and stabile; its advantages can be also used for finishing
optical elements on varieties of types such as plane mirrors and spherical mirrors.
Image density property of optical information recording microcapsule material
Author(s):
Weidong Lai;
Xiaowei Li;
Xinzheng Li;
Guangsheng Fu
Show Abstract
The microcapsules can act as novel optical functional material in which the optical recording substance such as
color-forming substance, photoinitiator and prepolymer are encapsulated. In this paper, the microcapsules with average
particle diameter of 300nm are prepared with interfacial polymerization method. The optical responding character of the
microcapsule is analyzed based on IR spectra and image density technique. Results show that the microcapsule material
encapsulated prepolymer TMPTA and photoinitiator Irgacure-ITX, TPO has thermal phase-change at 140°C, at which
the penetrability of the microcapsule has the highest efficiency. With the increase of exposure time, the reduction in
absorption intensities of the prepolymer TMPTA are observed at 1635cm-1 of C=C stretching and 898cm-1 of C-H
stretching on the C=C molecular bond. Such a result can be ascribed to the double bond cleavage process of the
prepolymer TMPTA is initiated by the optical-exposed photoinitiator, and superpolymer network is formed. The image
density contrast between the unexposed and exposed microcapsule is enhanced with exposure time increased.
Study on experiment of grinding SiC mirror with fixed abrasive
Author(s):
Xu Wang;
Xue-jun Zhang
Show Abstract
A brand-new technology for manufacturing SiC reflecting mirror that is different from the traditional method is adopted,
which is called as fixed abrasive surfacing technology. Not only the new method achieves better mirror quality with
bigger diamond in diameter quickly , but also because of the fixed motion between the abrasive and workpiece and it
will be good for surface finishing. During experiment, material removal characteristic which is on SiC under certain
rotation speed and pressure by W7,W5,W3.5,W1.5 pellets has been tested. Through those removal curves, we come to a
conclusion that the technology not only has a higher removal rate, but also has much more stability. In addition, the
surface roughness experiment is mentioned. In the first stage, we achieved a mirror with surface roughness 42.758nm
rms with W7 pellets. The surface roughness is descending as we change pellets with smaller diamond in diameter . At the
end of experiment, a smooth surface with roughness 1.591nm rms has been achieved after using W1.5 pellets.
Experiment results indicate that the technology which manufactures SiC reflecting mirror with fixed abrasive is able to
replace the traditional slurry abrasive completely in certain finishing phase and also has a great foreground in
application.
Structures and graphics of spacial spherical parallel grids with laser direct writing
Author(s):
Changhong Hu;
Zhezhou Yu;
Zhe Wang
Show Abstract
For improving laser direct writing in spacial spherical parallel grids, some definitions and descriptions of spacial
spherical parallels structure are presented. According to the formational principle of spacial spherical parallels and
geometry of space about the parallel grids, the mathematic model of spacial spherical grids is built up. Through
analyzing the part area of spacial spherical parallel grids and the angles constituted of the parallels, the angle formula
and area formula of spherical parallel grids are deduced. The relation of "the exactly square arc-shaped" and "the
irregular square" of the spherically parallel grids are studied. The program of these formulas is composed. And some
experiments are made to show its validity.
Transfer matrix method and dispersive formula of light in thin films
Author(s):
Hong-xia Dai;
Qi-neng Liu
Show Abstract
Using boundary conditions of electromagnetic waves , a new transfer matrix method that study electromagnetic waves in
thin films and a dispersive formula of 1D photonic crystal are derived. Using the formula reflection and refraction of
light is studied, the forbidden band of 1D photonic crystal is studied. The transfer matrix method and the classic
characteristic matrix method are compared. The transfer matrix method can not only solve the problem that characteristic
matrix method can solve, the transfer matrix method can also solve the problem that characteristic matrix method can not
solve. Therefore the transfer matrix method is a more fundamental and wider range of application.
Design of aspherical surfaces for panoramic imagers using multi-populations genetic algorithm
Author(s):
Li-Ping Wang;
Zhong-zhu Liang;
Chun-Shui Jin
Show Abstract
A design method of aspherical surface for panoramic imaging system with two mirrors using multi-populations genetic
algorithms is proposed. Astigmatism induced by mirrors may significantly compromise image resolution. To solve this
problem, we induced algebraic expression of astigmatism in panoramic imager based on generalized Coddington
equation and theory of geometric optics. Then, we propose an optimization process for mirror profile design to eliminate
astigmatism and provide purposely-designed projection formula with aid of MPGA. A series of polynomial expressions
of aspherical surfaces are obtained and procedures of the design are presented. In order to facilitate ray tracing and
aberration calculation, even asphere surface model is obtained by using of hybrid schemes combining MPGA and
damped least squares. Finally, a prototype of the catadioptric panoramic imager has been developed and panoramic ring
image is obtained.
Three regions in the material removal rate with the increase of the concentration of abrasives slurry
Author(s):
YinBao Guo;
Wei Yang;
Qiao Xu;
YaGuo Li
Show Abstract
During chemical mechanical planarization polishing (CMP), with the increase of the concentration of abrasives slurry,
there are three regions of material removal rate (MRR). It is a noticeable phenomenon for several wafer material,
including copper, aluminum, tungsten, silicon and silicon oxide. In this paper, a new abrasion mechanism model in
solid-solid contact mode of the CMP, proposed by Luo and David, is revised to explain the three regions and two
transitions between these regions. Experiment data from fast polishing process (FPP) supports the prediction of material
removal rate regions.
Annealing induced optical properties of YSZ thin films prepared by EB-PVD
Author(s):
Chao-Yang Li;
Guang-Jian Xing;
Yong-Jun Yang;
Wei Jiang
Show Abstract
In this study, YSZ thin films with different Y2O3 content have been prepared by electron beam evaporation on different
types of substrates. The film properties such as surface roughness, microstructure, refractive index and transmission
spectra were characterized by using Scanning Probe Microscopy (SPM), X-ray diffraction, SEM, ellipsometer and
spectrophotometer respectively. The results indicate that the film properties and microstructure correlate with the
annealing process dramatically. It is found the film structure undergoes from amorphous to tetragonal phase then
ultimately to tetragonal and monoclinic phase with the temperature increasing from 100 to 1100°C, while the surface
roughness increases from 1.3 to 24.6nm, and the refractive index varies from 1.86 to 2.02. XRD analysis shows the grain
size increased with the annealing temperature, the reduction of defect and surface compact incurred by the high
temperature process results in the increase of refractive index. Further investigations show that the optical properties of
YSZ films have little effect with the content of Y2O3 and the variation of refractive index is caused by the compactness
due to the crystallization of the films under high temperature.
Study of PZT actuated deformable aspheric polishing lap
Author(s):
Ziqiang Hu;
Ning Ling;
Junhua Pan;
Wenhan Jiang
Show Abstract
In aspheric mirror polishing progress, the deformable polishing lap can change the lap surface to fit the surface of
aspheric optical mirror. A novel method of designing deformable polishing lap is brought forward by using PZT
actuator. It consists of an aluminum disk which can change surface profile continuously under the control of PZT
actuators. When the deformable aspherical polishing lap moves on the surface of aspherical mirror, the needed
deformation of each PZT actuator is calculated at any location. After each PZT actuator deforming, the surface profile of
deformable aspherical polishing lap is changed to an off-axis surface of aspheric optical mirror at that location. In this
paper, the rational of the PZT actuated deformable aspheric polishing lap is introduced,and the calculation method of
deformation is explored also.By using finite element method, the deforming capability of the PZT actuated deformable
aspheric polishing lap is simulated to reform a hyperboloid mirror with diameter 350mm,k=-1.112155,R=840.0 mm.
Two type of PZT actuator arrangements are compared and analyzed. The results show that the PZT actuated deformable
aspheric polishing lap can reshape to fit the surface of aspheric mirror and the RMS is less than 2um.
Infrared antireflection DLC films by femtosecond pulsed laser deposition
Author(s):
Shuyun Wang;
Yanlong Guo;
Xiaobing Wang;
Yong Cheng;
Huisheng Wang;
Xu Liu
Show Abstract
Diamond-like Carbon(DLC) films are deposited by Ti:Sapphire femtosecond pulsed laser(800nm, 120fs-2ps, 3.3W,
1-1000Hz) at room temperature. The substrate is n-type Si(100), and the target is 99.999%-purity graphite. After a great
lot of experiments, optimal technical parameters, which are 1000Hz repetition frequency, 120fs pulse-width,
5cm-distance between target and underlay and 1014W/cm2 power-density, were used to deposite 443nm thick DLC film.
Raman spectrum measurement shows a broad peak with a center at 1550 cm-1 for all films, similar to those of typical
diamond-like carbon films prepared using other methods. And sp3-bond content reaches 67% analyzed by XPS. There is
no nick on the film when scraped 105 times by a RS-5600 friction test machine under the pressure of 9.8N. The infrared
transmittance increases along with the oxygen pressure when between 0.03 Pa and 2 Pa. The result shows that oxygen is
effective in etching sp2-bond content. The extreme infrared transmittance of Si slice deposited DLC film on single
surface is higher than 64% at 3-5μm, superior to 53% when being uncoated.
Influence of cutting velocity on surface roughness of KDP
Author(s):
Y. F. Peng;
Y. B. Guo;
Q. Xu
Show Abstract
The cutting parameters have important effects on the surface condition of KDP crystal by single point diamond turning.
In this paper, the characteristics of single point diamond turning have been researched, and a model that related the
residual height of surface to the cutting parameters is established. The influence of spindle speed and the feed rate of
cutting on KDP crystal surface roughness have been studied. Experimental results show that the surface condition can be
improved by decreasing the cutting feed rate of KDP crystal. Another important trend is that by decreasing the spindle
speed of the main-axis can't improve surface roughness efficiently while increasing the approaching velocity of KDP
crystal at the same time. The reason can be explained as that the high spindle speed will cause exceeded temperature of
the deformed zone, which will change the deformation mechanism of KDP crystal.
Influence of tool presetting error on surface accuracy in ultraprecision machining
Author(s):
Guo Li;
Bo Wang;
Xuesen Zhao;
Shen Dong
Show Abstract
First of all, kinematics model of the lathe is built by synthetically applying the robot kinematics theory and multi-body
kinematics theory. Secondly, the influence of tool presetting error in different position on surface radius of curvature and
surface accuracy is theoretically analyzed respectively. The variation of surface accuracy (P-V value) and central residual
height with tool presetting error is gained through theoretical approach. Finally, experiments are carried out on the
ultra-precision lathe for validating the analysis results.
Research on realization technique of precision forming for laser shock
Author(s):
Sumin Yin;
Shandong Qi
Show Abstract
The mechanism and process of laser shock forming metal sheet is analyzed, which requires laser beam irradiating
vertical to the surface of metal sheet. The metal sheet surface becomes complex after rough shocking and how to acquire
normal vector of the complex surface is researched. Intelligent sensor of high resolution and numerical control system is
adopted to configure a simple three-coordinate measurement system. The three-dimension information of the shocking
point and its adjacent points is acquired through calculation and measurement. The normal vector of shocking point is
estimated according to micro tangent plane. Two groups of data are measured for accuracy improvement and measuring
process is given, as well as error evaluation. The key problem of precision forming metal sheet under laser shock is
solved.
Experiment and simulation of micromilling process for plastic material
Author(s):
Yazhou Sun;
Qingxin Meng;
Haitao Liu
Show Abstract
According to elastic-plastic finite element theory, micro-milling nonlinear elastic-plastic finite element simulation
analysis on micro-optical component material aluminum alloy 2A12 is carried out.Simulation and analysis on milling
force, milling temperature, minimum chip thickness of micro-milling have been done, which provide the basis for
improving machining accuracy of micro-optical component. Use Johnson-Cook's coupled thermal-mechanical model to
build micro milling processing two-dimensional finite element model. By means of FEM analysis, simulation results
under different rotating speed, different feed per tooth, different tool edge radius are obtained and analyzed. By this way,
influencing regularities of kinds of factors on milling force and milling temperature are obtained. Finally experimental
study on influencing factors of milling force is done.
IAD-Si coatings on RB-SiC space mirrors for ultrasmooth surfaces
Author(s):
Lingdi Xu;
Xuejun Zhang;
Ruigang Li;
Feng Zhang;
Xu Wang
Show Abstract
To eliminate surface limitation caused by Silicon impurity in RB-SiC space mirrors, a relatively thick Si film is
deposited on well finished RB-SiC substrate by a new process-ion assisted depositing (IAD) to provide a better
polishable surface. Testing results of IAD-Si properties are provided, showing that the amorphous film has great thermal
shock resistance. Then, polishing experiments on 10±0.5μm thick IAD-Si layers are accomplished focusing on smoother
surface. Surface figure and micro-roughness of the coating after polished reach 0.026λ RMS (λ=0.6328nm) and less
than 0.5nm RMS respectively. Moreover, reflectivity of IAD-Si polished surface with reflective films increases higher
than 4.5% than that of RB-SiC in 360-1100nm. High reflectivity and desirable thermal property make IAD-Si an
attractive coating material for RB-SiC space mirrors.
Research of optical flats in pad polishing
Author(s):
Jian Wang;
Yinbiao Guo;
Yaguo Lee;
Qiao Xu;
Wei Yang
Show Abstract
The influence of polishing an optical workpiece with a polyurethane pad is examined in this paper, including material
removal rate, surface roughness and surface form error. Usually, optical polishing pitch is applied to polish optical
workpieces, but the material removal rate (MRR) of pitch is quite low, and polyurethane foam is thus substituted for
polishing pitch. With the polyurethane pad a much higher MRR is obtained. Surface roughness and surface error form of
workpieces are also examined. We are gratified to find that there is surface form error and surface roughness is
comparable to the result of pitch polishing.
Improved two-dimensional orthogonal cylindrical lens arrays optical system with controllable focus profile for uniform irradiation
Author(s):
Jianzhou Zheng;
Qingxu Yu;
Bin Dong;
Xiaojun Cao;
Shouhua Guan;
Qi Yang
Show Abstract
A novel orthogonal cylindrical lens arrays (OCLA) system has been proposed to obtain two-dimensional (2D) uniform
irradiation with controllable focus width and transformation of beam-shape at the same time. The system is composed
of two pairs of mutual OCLA and aspheric lens. Based on adaxial matrix optics and scalar quantity diffraction integral
theory, the principle of this system with controllable focus profile is analyzed and optimum design of system parameter
are presented in detail respectively. The simulated results show that by a suitable choice of system parameters
two-dimensional uniform focusing of laser beams with controllable focus width from several hundred microns to several
millimeters can be achieved. And the system converts a circular laser beam into a flat-top square focal spot of steeper
edges without side lobes. In order to confirm our theoretical considerations, with Zemax optical design software, confirm
regular focus width with the variation of the distance between two groups of mutual OCLA, the shape and intensity
distribution of focal spot is confirmed in agreement quite well with theory.
Research on the surface of a nonspherical lens with photosensitive colophony
Author(s):
Fu Zhao;
Ping Wang;
Yanjue Gong;
Hongbing Xin;
Chunling Meng;
Hui Zhu
Show Abstract
This paper does research on the shrinkage deformation caused by photosensitive colophony solidification in
manufacturing aspheric surface lens. With Finite Element Analysis, Orthogonal Experiment, and BP Neural Network
methods, the relationship between the shrinkage deformation of aspheric lens and structure parameters is built up. With
the mathematic model, the shrinkage compensable software for aspheric lens manufacturing is compiled to find out the
original shape after the shrinkage deformed shape is given. As a result, the mould surface curve is easily obtained in
accordance with the given aspheric lens shape.
Manufacturing of the 1070mm F/1.5 ellipsoid mirror
Author(s):
Peiji Guo;
Jingchi Yu;
Yaoming Zhang;
Gufeng Qiu
Show Abstract
The manufacturing procedure of a φ1070mm in diameter F/1.5 ellipsoid mirror is introduced in detail. For testing the
rough-ground surface, guiding shaping and fine grinding, a three dimension X-θ-Z profilometer is developed, the
instrument measures surface profiles with 1μm accuracy and the biggest mirror being tested is φ1200mm in diameter.
During polishing and fine figuring, we chose null test by null corrector with point source at infinity, the designed null
corrector includes two piece of lenses and the designed residual wave front aberration is less than
0.008λ(λ=0.6328μm)PV. For avoiding the influence of gravity deformation during polishing and testing, a kind of
support system with multipoint unequal support force is developed by applying FEA-based optimization. The mirror was
finally figured to the shape accuracy of 0.016λRMS.
Fast tool servo system for online compensation of error motion on an ultraprecision lathe
Author(s):
Xiaohui Wang;
Tao Sun
Show Abstract
In order to obtain high accuracy and a fine surface finish of large area workpiece, position control of machine tool has
become the main concern to achieve high precision position control. In this system, diamond turning with a fast tool
servo (FTS) driven by a piezoelectric actuator along with a capacitive displacement sensor was chosen as the fabrication
method. A laser interferometer is implemented to measure the straightness error of the translational slide accurately. The
detected error signals are compensated by the FTS during the cutting process. To achieve better tracking performance,
proportional integral (PI) feed back control with a feed-forward predictor is implemented. Experimental results show that
the FTS can effectively and successfully compensate the straightness errors of the X-axis translational slide of the
miniature ultra-precision lathe.
Smoothing treatment of high order aspherical surface
Author(s):
Jianfeng Ren;
Binfei Dai;
Guanghua Xu
Show Abstract
Mass production of high order aspherical lens can only use CNC fabrication system. The moving tools belong to CNC
system can only be controlled by scattered point. To make manufacturer easy to fabricate high order aspherical lens, it
should keep surface smooth that's means there is no sharp oscillation of tool during working process. Generally, the
smoothing surface is of c1 and c2 continuous. It is known that c1 ad c2 continuous standing for height sequence and radius
sequence of special point sequence in different direction are continuous.
In this paper, we introduce a method to judge surface smoothing and propose a method to prevent high order aspherical
lens surfacefrom being bad smoothingness. This method proves mess production by Mason optics for several years.
Methods for increasing the etching uniformity of ion beam multiple mask
Author(s):
Xiaobo Zhang;
Ying Xiong;
Qiang Liu;
Yangchao Tian
Show Abstract
With uniform illumination, multi-step diffractive optical elements (DOE) are fabricated with ion beam multiple mask
etching technology. According to the technical process of ion beam multiple mask etching on DOE, a distribution of
surface error based on LKJ-150 ion beam etching machine is presented. Numerical analysis indicates that the surface
distribution of etching error results in lower performance of multi-step DOE, which consumedly reduces the uniformity
of target field with uniform illumination. After each etching process, the sample i.e, multi-step DOE fabricated by
LKJ-150 ion beam etching machine is measured. Through measurement data, we get the etching error. On the basis of
etching error, the mask can be made. Numerical analysis shows this method can reduce the impact of surface error on
the performance of DOE and increase the etching uniformity of. ion beam multiple mask
Novel method for optimizing polishing tool-path in CCOS based on weighted-iterative algorithm
Author(s):
Wei-jie Deng;
Xue-jun Zhang;
Xiao-kun Wang;
Xu Wang
Show Abstract
In Computer Controlled Optical Surfacing (CCOS), polishing tool-path is the base of solving other control parameters
such as dwell time. In order to improve the fabrication results of polishing off-axis aspheric, a novel method to optimize
the tool-path is discussed in this paper. The optimizing method named weighted-iterative algorithm is according to the
balance principle of the particle system. The power factor of each dwell point represents the requirement of dwell density.
Considering the factors which influence the polishing result, the power factors cosist of three elements include constant,
error distribution and dwell distance of workpiece edge. The tool-path is solved by numerical iterative method. In the
end, an error data is simulated with actual parameters using the matrix-based algorithm with two different tool-paths.
The one is X-Y uniform spacing model and the other one is to optimize it based on the first. The comparison shows that
the results of the optimized one are much better than traditional one, especially the rms convergence rate. Theory of the
algorithm is simple and exercisable, and it satisfies practical requirement as well.
Effects of thickness and substrate temperature on the electrical and optical properties of In2O3-ZnO films
Author(s):
Yu Pei;
Fachun Lai;
Limei Lin;
Liqin Fan;
Yan Qu;
Rong Chen
Show Abstract
The influences of thickness (d) and substrate temperature (Ts) on electrical and optical properties of In2O3-ZnO (IZO)
films are investigated. IZO films are deposited on quartz substrates by reactive direct current magnetron sputtering. The
target is 80 wt.% In2O3 and 20 wt.% ZnO mixtures. d of the films deposited at room temperature varied from 63 to 651
nm. Ts of the films with thickness of about 200 nm varied from room temperature to 400 °C. Transmittances of the films
are measured by spectrophotometer. The electrical properties such as resistivity, carrier concentration and mobility are
studied by van der Pauw method. Experimental results show that the resistivity (ρ) monotonously decreases from about
1.2 × 10-3 to 5.0 × 10-4 Ωcm when d increases from 63 to 300 nm. As d=160 nm, the average transmittance in visible
spectral region has a maximum (87%). Additionally, the average transmittances in visible spectral region for all the films
deposited at different Ts are about 82%, but the transmittance in near infrared spectral region decreases with the increase
of Ts. When Ts increases from 100 °C to 400 °C, ρ and mobility monotonously decrease, but carrier concentration
increases.
Investigation of conductive and transparent Al-doped ZnO/metal dual-layer films by magnetron sputtering
Author(s):
Liqin Fan;
Fachun Lai;
Limei Lin;
Yu Pei;
Yan Qu
Show Abstract
Transparent conductive Al-doped ZnO (AZO)/metal (Ag or Cu) dual-layer films were deposited on glass substrates by
direct current magnetron sputtering at room temperature. AZO layer thickness was about 30 nm. The thickness of Ag
layer changed from 4.0 to 12.0 nm, and the thickness of Cu layer varied from 2.7 to 8.1 nm. The influence of metallic
layer thickness on the structure, optical and electrical properties of dual-layer films was analyzed. Ag (111) crystalline
peak was clearly observed in X-ray diffraction pattern as Ag layer thickness increases to 12.0 nm. For AZO/Cu films,
besides the Cu crystalline peaks, there are copper oxide crystalline peaks. As Ag layer thickness increases from 4.0 to
12.0 nm, sheet resistance decreases from 6.37 to 3.91 Ω/sq and the average transmittance in the visible spectral region
decreases from 83.7% to 72.6%, respectively. The average transmittance of AZO/Cu films with different Cu layer
thicknesses is between 70.7% and 75.5%. The lowest sheet resistance is 19.2 Ω/sq when Cu layer thickness is 8.1 nm.
The performance of the dual-layer films was also compared using a figure of merit. The results show that the high quality
transparent and conductive films can be achieved by using AZO/metal dual-layer films.
Optical and electrochemical properties of the protonic state electrochromic device: NiOx/Ta2O5/WO3-x
Author(s):
Zhuying Li;
Liu Ye;
Minliang Zhang;
Chonglou Shun
Show Abstract
In the present investigation, the electrochromic properties of a protonic solid state device: WO3 / Ta2O5 / NiOx prepared
at room temperature (300K) is reported. The non-stoichiometric tungsten oxide thin film (100nm), the tantalum oxide
thin film (360nm) and the nickel oxide thin film (50nm) are prepared by RF magnetron sputtering technique on ITO
coated glass; The transmittance variation for Li+ device is +30% and for Ta+ device is -2%. The optical band gap for
WO3 film is 3.11eV, for WO3 / Ta2O5 / NiOx multilayer films is 2.98eV.
Optimization of actuator forces in shaping aspheric surfaces on ultrathin mirrors
Author(s):
Chunmei Zeng;
Jingchi Yu
Show Abstract
Shaping aspheric surfaces on ultra-thin spherical mirrors is a new idea which combines optical fabrication and
measurement, elasticity mechanics, active optics, etc. It can relieve pressures of fabrication, test and cost using
large-aperture aspherical mirrors. Both appropriate actuator arrangement and efficient loads are the keys to achieve
shaping aspheric surfaces. In order to determine the best actuator loads, the optimization of actuator forces is studied in
this paper. Firstly, an example of shaping aspheric surfaces on a large off-axis ultra-thin mirror is presented, and its
actuator arrangement and preliminary actuator loads satisfying surface accuracy have been given. Secondly, the
corresponding relation between actuator forces and aspherical figure are analyzed, and the optimization objective is set
up. Finally, the sequential quadratic programming (SQP) method for nonlinear constraint problem is applied to calculate
best actuator forces. Simulation results indicate that the RMS aspheric surface error is significantly improved, and the
number of actuators is also obviously decreased when the RMS error remains unchanged.
Moment acting on workpiece in solid abrasive plane lapping
Author(s):
Jiandong Yang;
Chunlin Tian;
Ziqiang Hao;
Haiyang Yang
Show Abstract
According to relative movement rule between lapping tool and workpiece in solid abrasive plane lapping this paper takes
a point on the workpiece as a differential unit to analyze force and moment acting on it, then we integratefor whole
workpiece, obtain the join moment acting on workpiece and get change relationship of join moment with workpiece
size and eccentricity. Because there is a transcendental function in integral equation, analytical result of join moment of
the lapping tool acting on the workpiece can not be got. By means of computer this paper gets digital results and draws a
three-dimensional figure of moment changing with workpiece size and eccentricity, which proposes a theoretical base for
selecting lapping parameters.
Influences of cutting section and corner radius to cutting force in diamond turning
Author(s):
Guojun Dong;
Chengshun Han;
Shen Dong;
Tao Sun
Show Abstract
During diamond turning process of metal mirror, the variations of cutting resistance are studied in this paper. In the
process of arc blade diamond turning, the diameter dependent variations of cutting force were explored, through the
calculation of cutting section area, deformation coefficient of cuttings and cutting force. The study showes that the ratio
of main cutting force Fz to radial force Fy decrease with the increase of corner radius and that unit cutting force
increases with the decrease of cutting section. This helps the choice of diamond turning tools and machining parameters.
Research on high-speed deposition thermodynamics characteristic for DLC thin film by RF-PECVD
Author(s):
Mi Zhu;
Changxin Xiong;
Changcheng Yang
Show Abstract
Diamond-like carbon (DLC) thin film is often used on the surface of Infrared windows as the protecting film. PECVD
method is one of the principal ways to obtain DLC film.
The key factors, which affect the deposition rate of DLC film, and how to achieve high speed rate have been analyzed in
this work. We prepared high-speed deposition DLC film samples on Germanium and Silicon by RF-PECVD, and the
relationships between deposition rate, RF power, vacuum degree and dimension size of substrates, deposition
temperature have been investigated. We found that when the deposition temperature rises, the deposition rate would rise
correspondingly but fall down later.
According to MIL-48616 environmental stability standards, the environmental and physical durability test results and the
curve of spectrum are also presented in detail in the paper.
Transparent conductive titanium-doped indium oxide films prepared by direct current magnetron sputtering
Author(s):
Limei Lin;
Fachun Lai;
Yan Qu;
Rongquan Gai
Show Abstract
Titanium-doped indium oxide (ITiO) thin films are deposited by direct current magnetron sputtering with different
sputtering powers from a titanium-doped indium oxide ceramic target. The electrical and optical properties,
microstructure characteristics of ITiO thin films are examined. The results demonstrate that all films show
polycrystalline structure and the crystallinity is improved with increasing sputtering power. The resistivity of the ITiO
films decreases with increasing sputtering power, and the lowest resistivity is about 4.13×10-4 Ωcm with sputtering
power of 180 W. The average transmittance above 80% is obtained for the ITiO films in a wide spectral range of
400~1500 nm.
Optical properties of In-doped TiO2 thin films
Author(s):
Mingliang Zhang;
Zhuying Li;
Cunlou Sun;
Shaohong Yang
Show Abstract
A series of In-doped TiO2 thin films are deposited by magnetron sputtering technique on glass substrates. The quantities
of In-element in these thin films are increased gradually. Scanning electron microscope, X-ray diffraction spectroscopy
and UV-visible spectroscopy are used to investigate the surface morphology, crystal structure and absorption spectrum of
film. The analysis of SEM results show that the surface morphology of film is granulated, and that the size of the
granules in the film is about 20~30nm. The analysis of XRD results indicates that the crystalline structure of film
cannot be confirmed from XRD patterns. In-element reduces the diffraction intensity of TiO2 film. Absorption spectrums
suggest that absorption peak and absorption edge of the film change regularly according to variety of In-doped. The
calculated value of optical constant of the film, bandgap, also changes regularly. O2 has significant effects on optical
performance.
Research on ultrathin mirror fabrication and demonstration of an Ø500mm ultrathin mirror
Author(s):
Qitai Huang;
Peiji Guo;
Jingchi Yu
Show Abstract
If an ultra-thin mirror with 2-4mm thickness is applied on deployable space optical system, the mass of the system can
be decreased while its diameter increasing, and the mirror surface active adjust is achievable. The advantage of the
ultra-thin mirror compared with traditional light-weighted mirror described above make ultra-thin mirror a strong
competitor for next generation space optical system. Many important institutions have researched on fabrication of
ultra-thin mirror. Contrary, the advantage of ultra-thin mirror application is just the disadvantage in the process of
fabrication. Because of the ultra thin thickness, large distortion will be caused by the pressure of grinding and polishing.
Also, the distortion caused by temperature alteration and stress can not be ignored. These will all affect the precision of
the surface and increase its fabrication difficulty. The factors will possibly cause surface distortion and relevant control
method in the process of fabrication and measurement are discussed in this article. &slasho;195mm and &slasho;340mm ultra-thin
mirror fabrication experiments are carried out and ameliorations of fabrication technology are summarized form these
experiments. Finally, a &slasho;500mm ultra-thin mirror has fabricated and the experiment of active adjust indicates that this
mirror can achieve acceptable surface quality.
Wide-angle and broadband nonpolarizing parallel plate beam splitter
Author(s):
Wenliang Wang
Show Abstract
When being used at oblique angels of incidence, the reflectance and transmittance of thin film exhibits strong
polarization effect. For much application about beam splitter, this effect is undesired and should be reduced. Up
till to now, most theoretical results published on non-polarizing beam splitter are valid for a very limit
wavelength or angular range. Here, we present a beam splitter with low polarization, operating at 450 to 650nm
wavelength range and 40 to 50 degree incident angle range. The paper presents lossless periodic dielectric
multilayer in characteristic of low polarization in the working range of wavelength and incident angle range. The
configuration can be made with current deposition technology.
Effect of substrate bias and arc current on AlN films
Author(s):
Haifeng Liang;
Hengping Liu;
Yang Zhou
Show Abstract
Aluminum nitride (AlN) thin films are deposited by means of d.c. magnetism filter arc deposition. Various processing
parameters, such as 0-V, -50V, -100V, -150V bias voltage and arc current of 55A, 75A and 90A, are optimized.
Ellipsometry, X-ray diffraction (XRD) and fourier transform infra-red (FTIR) are carried out to characterize AlN thin
films' properties. For 0-V and -50V bias, AlN films, prepared on silicon substrate, are show with 002 preferred
orientation, and the films are oriented to 100 at the -100V bias. However, the films has no preferred orientation when
using -150V bias voltage. Furthermore, the films are also shown without preferred orientation at 50A arc current (with
-50 bias voltage), and presented obvious preferred orientation at 75A and 90A. In addition, ellipsometry and FTIR
spectrum has shown that all the films extinction coefficient are near to zero and refractive index varied from 1.7 to 2.4.
The deposition rate increases with the decrease of arc current and decreases with the positive bias voltage. By combining
the spectrum of XRD and FTIR, the AlN films with good crystalline orientation, present obvious absorbing peak in To
(A1) or To(E1) vibration.
Primary optical system design for the optimization of light-emitting diode packages
Author(s):
Jian Zhang;
Zhi-wen Hu;
Hao-chen Qi;
Cheng-yue Liu
Show Abstract
Based on the particularities of illumination optical systems, the design of light-emitting diode (LED) primary optical
system is performed by using optical modeling and Monte Carlo non-sequence ray tracking method. The intensity
distributions of LEDs with different material and packaging parameters are obtained to get optimum values of reflector
cup and epoxy resin structure. The modeling and designing methods, including the optimized parameters, can provide
some referrence for LED primary optical system design.
Design of a detection system of highlight LED arrays' effect on the human organization
Author(s):
Shuwang Chen;
Guiju Shi;
Tongze Xue;
Yanming Liu
Show Abstract
LED (Light Emitting Diode) has many advantages in the intensity, wavelength, practicality and price, so it is feasible to
apply in biomedicine engineering. A system for the research on the effect of highlight LED arrays to human organization
is designed. The temperature of skin surface can rise if skin and organization are in irradiation by highlight LED arrays.
The metabolism and blood circulation of corresponding position will be quicker than those not in the shine, so the
surface temperature will vary in different position of skin. The structure of LED source arrays system is presented and a
measure system for studying LED's influence on human organization is designed. The temperature values of shining
point are detected by infrared temperature detector. Temperature change is different according to LED parameters, such
as the number, irradiation time and luminous intensity of LED. Experimental device is designed as an LED arrays pen.
The LED arrays device is used to shine the points of human body, then it may effect on personal organization as well as
the acupuncture. The system is applied in curing a certain skin disease, such as age pigment, skin cancer and fleck.
Analyzing and processing the images of self-organized patterns
Author(s):
Xiaohong Yang;
Shuhua Liu
Show Abstract
Some practical methods are presented for analyzing and processing the images of self-organized patterns with Matlab 6.5,
including "adumbrating the patterns", "adjusting the images", "locating the pattern units", "describing the brightness
distribution", "Fourier transformation", and so on. Adjusting the images is to make some characteristics of the patterns
more evidently. The method we use for adjusting the patterns is mapping the brightness of the original patterns to a new
range of value. The spatial brightness distribution in the patterns can be obtained with the function "improfile", which
computes the intensity values along a line or alone specified points in the image by using interpolation arithmetic. the
types of the self-organized patterns can be determined by obtaining the spatial frequency spectrum of the patterns using
Fourier transform. The location of the units is pinpointed by convolution operation between the unit digital picture and
the pattern digital picture.
Optical design of long focal length and wide field on an aerial CCD camera
Author(s):
Xiaowei Cheng;
Ying Che;
Changxi Xue
Show Abstract
Reconnaissance range and image resolution are increasingly paid more attention to with the development of airborne
reconnaissance, the optical system should be in characteristics of long focal length and wide field. At the same flight
altitude, the wider field can enlarge ground covering width and increase the reconnaissance range Longer focal length
can improve ground sample distance (GSD). Merits and advantages of reflecting system, catadioptric system and
refractive system were represented, with the help of code V software, a refractive system was designed to meet the
requirements, Optical material with special dispersion was adopted to remove second order spectrum. It has a focal
length of 903mm, with the field angle of 4.5°×4.5°, the size of CCD pixels is 10um×10um, spectral scope is from
0.43um to 0.74um, modulation transfer function(MTF) is all above 0.5 in whole field when spatial frequency is at
50lp/mm, distortion is less than 1%, image quality reaches the diffraction limit. The system with long focal length and
wide field can satisfy the demand of the wide ground overlay area and high resolution, and can apply in high altitude
photograph.
LED optical engine based on a rectangular CPC for microprojection display
Author(s):
Shu-ying Wang;
Wen-jun Sun;
Wen-bin Bu;
Zhong Meng
Show Abstract
A light uniformizing algorithm based on rectangular CPC is presented for micro-projection display. The designed optical
engine with rectangular CPC consists of LED, fly's-eye lens and micro-display panel DMD. The light uniformity on the
micro-display panel and energy efficiency of the optical engine with rectangular CPC is analyzed by means of software.
Experimental results show that the proposed light uniformizing algorithm and system compared with other uniformizing
light algorithm and system have advantages such as lesser capacity, lesser Etendue, higher light uniformity more than
92% and higher energy efficiency of 43% to meet the needs of micro-projection display.
Vector analysis of the characteristics of diffractive microlens having common focus for a number of wavelengths
Author(s):
Yuling Liu;
Chenghua Sui;
Pinggen Cai
Show Abstract
Not only harmonic diffractive microlens has a common focus for a number of discrete wavelengths, but also the ordinary
diffractive microlens which is modulo 2π has a common focus for a series of discrete wavelengths, the essence reason of
this phenomena is the same, such wavelengths with common focus are called harmonic wavelengths. A number of
focuses are generated when monochromatic light wave illuminates an ordinary diffractive microlens. The different focus
corresponds to different diffractive order. A series of harmonic wavelengths are focalized by a diffractive microlens at a
common focus corresponding to their own diffractive orders. One can design achromatic aberration microlens by using
the above characteristic of diffractive microlens. In this paper the diffractive microlens design method and the formula of
focallength for various diffractive orders are accounted for. A multilevel diffractive microlens is analyzed by using
finite-difference time-domain (FDTD) method. Two-dimensional electric field amplitude distributions for different
incident harmonic wavelength are given. The electric field along optical axis for the harmonic wavelengths is plotted at
the same time. The results show that the harmonic wavelengths can have common focus. Furthermore, the shorter
harmonic wavelength has higher resolution, shorter focal depth, and more focuses than the longer ones.
Indium-tin oxide conductive films on flexible substrates deposited by the DC magnetron sputtering method
Author(s):
Nana Wang;
Junsheng Yu;
Hui Lin;
Shuangling Lou;
Yadong Jiang
Show Abstract
Indium tin oxide (ITO) films on flexible polyethylene terephthalate (PET) substrates with low square resistivity and
high transmittance in visible region are prepared by DC magnetron sputtering deposition method. The dependence of
electrical property of ITO films on substrate temperature and DC power is compared using PET and glass substrates. The
results imply that the change trend of electrical property of ITO films is similar no matter what kind of substrate is used.
Using the ITO-coated substrates as anode, organic light-emitting devices (OLEDs) consisted of
PET/ITO/NPB/Alq/Mg:Ag are fabricated. The electroluminescence performance of the flexible devices is comparable to
the identical devices made of ITO-coated rigid glass substrates.
Methods for improving ion beam etching uniformity of large-sized DOEs
Author(s):
Ying Xiong;
Xiaobo Zhang;
Gang Liu;
Ying Liu;
Dequan Xu;
Yangchao Tian
Show Abstract
DOE is often produced by lithography and ion beam etching. The etching depth error directly affects the diffraction
performance of DOE. The uniformity of ion beam etching depth is particularly important for large-sized DOEs in that
errors by ion beam etching uniformity would result in an obvious aberrant spot of intensity in the focal area of DOE,
which consumedly reduces the uniformity of target field in uniform illumination. On the basis of the KZ-400 ion beam
etching equipment the method of improving DOE ion beam etching uniformity is investigated. The step-by-step method
is used to improve the uniformity of ion beam etching, in which the etching time and location are adjusted. Experimental
result shows that in the range of 190mm along the major axis of ion beam source the etching uniformity of DOE
increases from ±5% to ±1.3%.
Preparation of TiN solar spectrally selective absorbing thin film by DC magnatron sputtering
Author(s):
Shuying Fu;
Zhenquan Lai;
Wei Zhong;
Xiurong Zhu
Show Abstract
TiN solar spectrally selective absorbing thin film with good spectrum absorbing selectivity is prepared by DC magnatron
sputtering, using Ti as target material and Argon as working gas, on Si(111) substrate. Research shows: when keeping
other technique parameter constant, with sputtering air pressure varied 0.35-1.5pa, cubic phase TiN thin films with a (200)
preferred orientation are Synthesized; and thin film prepared with a sputtering air pressure of 0.35pa, is compact and
uniform, with a golden colar and a film thickness of 132nm, shows the best crystallinity, least resistivity of 33.8Ω×cm
(close to bulk resistivity of TiN), with average absorptivity α of visible light-near infrared (wavelength ranges
400-1000nm) at 0.83, and maximum reflectivity R of infrared at 0.90. Through analysis of film structure, film thickness,
absorptivity and reflectivity, TiN thin film prepared with a sputtering air pressure of 0.35pa, has good spectrum
absorbing selectivity, and therefore has high application potential and value in heat absorpbing surface of solar collector
or photothermal conversion building material directly.
Design of a time-correlated single photon counting spectrometer based on PC
Author(s):
Xiu-feng Zhang
Show Abstract
The time-correlated single photon counting spectrometer uses a peculiar splitter technique so the time spread can be dynamically
and statically compensated. Design time-correlated single photon counting electronic system. Develop data collection and transfer
chip based on PC, analyzer is used to measure time-resolved spectrum by opening the time windows. The system theory
and design of the spectrometer are presented in detail, and the process of operation is introduced with the integration of
the system. The spectrometer can measure fluorescence life-span and time resolution spectrum of different samples.
Many standard samples have been measured and the data have been analyzed and contrasted. Experimental results show
that the spectrometer's sensitive is single photon counting, and fluorescence life-span and time resolution is picosecond
level.
Study on fabrication technology of silicon-based silica array waveguide grating
Author(s):
Yanjun Sun;
Lianhe Dong;
Yanbing Leng
Show Abstract
Array waveguide grating (AWG) is an important plane optical element in dense wavelength division
multiplex/demultiplex system. There are many virtue, channel quantity larger,lower loss, lower crosstalk, size smaller and
high reliability etc. This article describs AWG fabrication technics utilizing IC(Integrated Circles) techniques, based on
sixteen channel Silicon-Based Silica Array Waveguide Grating, put emphasis on discussing doping and deposition of
waveguide core film,technics theory and interrelated parameter condition of photoetch and ion etching. Experiment
result indicates that it depens on electrode structure, energy of radio-frequency electrode gas component,
pressure ,flowing speed and substrate temperature by CVD depositing film .During depositing waveguide film by
PE-CVD, the silicon is not reacted, When temperature becomes lower,it is reacted and it is easy to realize the control of
film thickness and time with a result of film thickness uniformity reaching about 4% after optimizing deposition
parameter and condition. We get the result of high etching speed rate, outline zoom, and side frame smooth by
photoresist/Cr multiple mask and optimizing etching technics.
Numerical simulation of selective laser sintering transient temperature field
Author(s):
Jian Xing;
Xiaogang Sun
Show Abstract
A numerical simulation pattern based on finite element algorithm is proposed for calculation of selective laser sintering
transient temperature field. The patter is based on the transient thermal radiation and the boundary conditions is
concerned soundly, particularly during the transient sintering the relation between thermal conductivity and transient
sintering temperature is set up on the basis of practical test to simulate practical sinter process. As a typical and
comprehensive sample, polystyrene SLS transient temperature field is analyzed. In the process of sintering the cube of
72mm×7mm×5mm, in case different parameters (laser power, scanning speed), both in a time the scanning line
temperature and in a point the temperature variation with time could realize. At a time, the simulation result accords with
the practical measurement result using the infrared thermometer. The results show the simulation transient sintering
temperature is 252°C and that of practical measurement is 241°C with laser scanning speed 2000mm/s and laser output
power 15W. the simulation transient sintering temperature is 313°C and that of practical measurement is 299°C with
laser scanning speed 1750mm/s and laser output power 40W. With the simulation system of SLS transient temperature
field developed in this paper, the SLS transient temperature field could be obtained rapidly and precisely to different
materials and parameters, the basis of selecting sintering parameters soundly and next analyzing of stresses and defects
were found firmly.
A new algorithm to locate the laser spot center at a sub-pixel level
Author(s):
Ruifang Ye;
Chun Lin;
Zhenheng Lin;
Xizhao Lu;
Xiaolan Chu;
Yuanqing Huang
Show Abstract
Laser is widely used in processing and measurement because of its fine directivity and concentrated energy. The quality
of processing and measurement are mostly determined by the location of laser spot. However, it is difficult to locate its
center. A new algorithm, based on Hough Transform and sub-pixel methods, is proposed to locate laser spot center at a
sub-pixel level. In this algorithm, Hough Transform is utilized to detect the profile, center and radius of circle spot at a
pixel level, and the centroid method and curve fitting method are utilized to locate the center to sub-pixel level.
Simulation and experimental results show that the algorithm offers great accuracy in position locating for laser spot. This
method can be used in laser processing and measuring system.
Transmission spectra dependence on the grating lengths of long period fiber grating fabricated by 800nm femtosecond laser pulses
Author(s):
Yongqin Yu;
Shuangchen Ruan;
Yi Huang;
Chenlin Du
Show Abstract
Femtosecond laser pulses with ultrashort time duration and ultrahigh peak power can cause the refractive index change
in transparent materials and micron scale machining precision. Long period fiber gratings (LPFGs) with different grating
lengths in the standard single mode fiber are fabricated. Using laser direct writing method, Femtosecond laser pulses
with pulse width of 200 fs at a center wavelength of 800 nm in air is applied as laser source. The transmission spectra are
studied in the range of 1510 nm to 1610 nm. The loss peak of 1552 nm, the transmission loss of 16 dB and the FWHM of
20 nm are obtained with the period of LPFG of 400 μm. According to the theory of mode field coupling for long period
grating, transmission spectra of LPFGs are numerically simulated depending on the grating length.
Integrated development environment based on resource library for intelligent opto-electric instruments
Author(s):
Ming Cen;
Ping Wang;
Xingfa Liu;
Jianchun Jiang;
Kaibi Zhang
Show Abstract
Intelligent opto-electric instruments are synthetically products that are involved with optics, mechanics and electronics.
An effective development platform is necessary for efficient development. According to the conception of integrated
development and manufacture, an architecture of integrated development environment based on resource library and
resource management is presented to resolve the shortcoming of weak reusability and portability of resource, long
periods of development and weak openness of existing platform. The development environment provides a suite of
standard resource integration and management interface to integrate and regulate existing models, algorithms, tools and
components. Then reusable typical resource library is established by adding third party resource that accords with the
interface defined. Resources in library are expressed as reusable components. System modeling, rapid prototype
developing and online simulating and testing can be implemented rapidly and reliably by utilizing corresponding
resources in library, so technique difficulty and development periods can be reduced, and development efficiency is
improved. Because of describing resource by metadata and XML, the architecture is flexible and open, and can be
improved continuously to adapt to development and upgrade of various intelligent opto-electric instrument to meet the
requirement of efficient integrated development and manufacture perfectly.
Technique of adaptive laser beam shaping based on stochastic parallel gradient descent
Author(s):
Huizhen Yang;
Yuran Liu;
Xinyang Li;
Xunyin Bi
Show Abstract
An adaptive beam intensity shaping method based on the combination of a 61-element deformable mirror and stochastic
parallel gradient descent algorithm is presented. This technique can adaptively adjust the voltages of 61 actuators on the
deformable mirror to reduce the difference between target beam shape and actual beam shape. Numerical simulations
results show that within the stroke range of the deformable mirror, the system can be well used to create Gaussian and
super-Gaussian beam profiles on the focal plane that closely match the desired target parameters.
Ultraprecision finishing process integrated ELID grinding and MRF for BK glass
Author(s):
Shaohui Yin;
Hitoshi Ohmori;
Yoshihiro Uehara;
Yongjian Zhu;
Fengjun Chen;
Kejun Zhu
Show Abstract
An ultra-precision synergistic finishing process integrated MRF and ELID grinding was proposed for shorten total
finishing time and improve finishing quality. Sets of ultra-precision experiments were carried out to grind and finish
some optical glass BK materials. ELID grinding, as pre-finishing, was employed to obtain high efficiency and high
surface quality; and then, MRF, as the final finishing, was employed to improve further surface roughness and form
accuracy. BK13 plane glass was processed by integrated ELID grinding using #4000 wheel and MRF. After ELID
grinding, λ/5 P-V was obtained, and then, MRF 30 minutes, the form accuracy was improved to λ/28 P-V. Likewise,
curvature BK7 glass lens was also used to test. After ELID grinding using #4000 wheel, form accuracy λ/5 P-V and
surface roughness 261 nm rms were obtained; and then, MRF 17 minutes (2 cycles), the form accuracy and the surface
micro-roughness were improved to λ/18 P-V and 0.56 nm rms. By applying the ultra-precision synergistic finishing
process of ELID-grinding and MRF, the glass materials could be finished to sub-nanometer surface micro roughness and
~20 nm figure accuracy in a short time.
Analysis of parameters in fluid jet polishing by CFD
Author(s):
Chun Yan Shi;
Jia Hu Yuan;
Fan Wu;
Yong Jian Wan;
Yu Han
Show Abstract
Parameters of fluid jet polishing (FJP) are analyzed in this paper. According to the theory of Computational Fluid
Dynamics, we simulated the process of fluid jet polishing by using Computational Fluid Dynamics software. Based on
the results of simulation, the distribution of flow field is showed and analyzed, and the distribution of important process
parameters including the velocity and pressure of work piece wall, the grain concentration of slurry are gained. By
analyzing the characteristic of FJP and the influences of Parameters to FJP, it is found that the distributions of pressure
and velocity on work piece wall are related to the distribution of removed material, and the impact angle influences the
distributions of velocity and material removal. By simulating fluid jet polishing process with different impact angle
models, we found the optimal impact angle to the distribution of material removal.
Geometric models of precision machining conic optical asphere
Author(s):
Cheng-Shun Han;
Shen-Wang Lin;
Long-Jiang Zhang
Show Abstract
To enhance the machining precision before polishing, 2-axis NC machining method is put forward for conic aspheric
optical mirror manufacturing. The integrated geometric model and the corresponding machining parameters, such as
suitable radius of tools, tool path interval, horizontal feed and axis feed are presented based on precision assurance for
lower manufacturing cost and higher production. The feasibility of the scheme and the reliability of the model are proved
with numerical examples by computer simulation. Therefore, it could provide a reference for NC control software system
in producing quadric optical mirrors and for other kinds of aspherical surface manufacture.
3D finite element simulation and experiment of residual stress on the cutting surface
Author(s):
Haitao Liu;
Yazhou Sun;
Zesheng Lu
Show Abstract
According to elastic-plastic finite element theory, three-dimensional nonlinear elastic-plastic finite element simulation
analysis on optical component material aluminum alloy 2A12 is carried out, and residual stress on machined surface is
predicted and calculated, which provide the basis for improving the machining accuracy of optical component.
Johnson-Cook's coupled thermal-mechanical model is used as work piece material model, Johnson-Cook's shear failure
principle is used as work piece failure principle, coupled thermal-mechanical hexahedron strain hybrid modules and
adaptive grid are used to mesh, while friction between tool and work piece uses modified Coulomb's law whose slide
friction area is combined with sticking friction. By finite element analysis, simulation results of residual stress on the
machined surface is gained under different cutting velocity, tool edge radius, and by analyzing and comparing the results,
the basic influence law of various factors on residual stress on machined surface is found.
Study on the calculation and application for asphericity of rectangle off-axis aspherics
Author(s):
Jun-feng Li;
Bin Xuan;
Peng Wang;
Xiao-ping Chen;
Hong Zhang;
Jing-jiang Xie;
Shu-mei Song
Show Abstract
Asphericity which affects the manufacturing process and the grinding quantity is an important parameter of optical
aspherics. In this paper, the approximation, the least square fitting, wavefront aberration, sag methods are given for the
calculation of optical asphericity. The effects of different definitions of optical asphericity are analysed to optimize the
process of manufacture. A sag method is presented to solve the best-fit sphere and asphericity for an off-aixs aspheric
mirror with a rectangle aperture of 180mm×145mm, and polishing quantity and distribution plots are given. The optical
manufacturing and testing technology for different choices of best-fit spheres and asphericity are described and analyzed.
Therefore, proper definition of optical asphericity which is useful to manufacturing is very important for optical
fabrication and test.
Optical system of large relative aperture and wide field using aspheric corrector for detecting
Author(s):
Ming Ming;
Jianli Wang;
Jingxu Zhang
Show Abstract
The magnitude requirement of space target detecting determines that the image of detecting telescope should have
several performances: small spots, small 80% encircled energy diameter and good MTF(Modulation transfer function).
So the aperture and field of view of optical system have some demands accordingly. The larger aperture, the more energy
that telescope collects and higher magnitude the telescope detects; the wider field of view, the more extensive range
which the telescope searches. Now most of ground telescopes whose apertures are from 500mm to 1000mm is on-axis
optical system, so wide field of view becomes the most importance problem.
To obtain large relative aperture and wide field of view, the paper introduces a catadioptric telescope with small aperture
aspheric refractive corrector, whose conic surface will be used to remove the aberrations due to large relative aperture
and wide field of view. As to the optical system, there is only one aspheric refractive corrector, and it is relatively easy
for manufacturing because of its concave figure and normal material. The paper gives the example, and optimizes this
optical system with ZEMAX program. And then the paper provides a specific analysis program for testing the aspheric
refractive corrector. The aperture of this optical system is 750mm, and its relative aperture is 0.82, and the field of view
is 3.6° diameter(diagonal). Its structure is simple and the image quality is also very good.
Reversible dark-center diffraction of metal film in micromachining
Author(s):
Jin Xie;
Changhe Zhou
Show Abstract
When we utilized femtosecond laser to micromachine Cr film with glass substrate, we found reversible dark-center
diffraction of the transmitted probe beam passing through the chromium film and reversible bright-center diffraction of
the reflected probe beam from the chromium film, which are induced by the pump femtosecond laser. The dark-center
diffraction of the transmitted probe beam and the bright-center diffraction of the reflected probe beam appear and
disappear with and without the pump beam. A view of diffractive optics with binary phase plate is put forward, which
explains the reversible dark-center diffractive optical phenomenon. The pre-ablated hole on the metal film can be
regarded as a uniform light filed without phase modulation, the surrounding circular part around the pre-ablated hole can
be regarded as "phase modulated". Therefore, this diffraction optic view might be helpful for us to understand the phase
change of the metal film introduced by the femtosecond laser pulse.
Ultraprecision machining of steep aspheric parts with large sagittal height
Author(s):
Lin Mu;
Rui Zhao;
Qiming Xin
Show Abstract
Problems occurred during machining steep aspheric parts with large sagittal height on double-spindle diamond turning
machine are presented and the main reasons of the problems are described. And methods of solving these problems are
also suggested. When we machine steep aspheric parts with large sagittal height on a 2 axis diamond turning machine,
we have such problems as difficult control of part edge accuracy, poor roughness and rapid wear of the cutting tool. The
main reasons for these problems lie in: 1) Measurement. To make accurate measurements, the measurement range of
the profilometer must fall within the sagittal heights of the aspheric parts, and the measurement angle must also meet the
requirements, an insufficient measurement angle, for example, will have a big impact on the measurement and
fabrication accuracy of such parts; and 2) Machine and tool, firstly, the diamond cutting tool will suffer a very big force
when turning the edge section, resulting in bigger micro-vibration in the tool and tool post, thus affecting the part
accuracy and surface roughness. Secondly, the machine itself has location errors in axes X and Z during the processing,
leading to the severest destruction in the steep section of the aspheric part by their resultant force. Lastly, anisotropy of
diamond cutting tool hardness. The indentation hardness of the diamond is maximum in the direction of <1.0.0> of face
(100) and the front clearance has the best strength at tool point in the direction of <1.0.0>. When cutting a steep aspheric
part with large sagittal height, a bigger included angle of the diamond tool point arc will be used, and there will be a
more deviation from the <1.0.0> lattice direction. So the tool hardness is consistently decreased, resulting in a rapid wear
of the cutting tool when turning the steep section of the aspheric part, thus the accuracy and roughness in machining an
aspheric part become more difficult to control. The paper is concluded with the solutions of turning steep aspheric parts
with large sagittal height. Efforts have been made to reach an accuracy within 1.5 um, Ra 0.007 um (mold insert), and no
apparent tool marks on the surface when machining steep aspheric parts with large sagittal height on double-spindle
diamond turning machine.
Research on wheel error compensation of aspheric grinding machining
Author(s):
Liangyu He;
Yinbiao Guo;
Hao Huang;
Zhenzhong Wang;
Jian Wang
Show Abstract
This paper presents a compensation system based on wheel online dressing and online measuring. Because of its
excellent dressing performance, the Green-Carbon wheel Dresser was chosen to dress the diamond wheel. And a
measurement system was put forward, which included the method of diamond wheel arc detecting with displacement
sensor, radius filtering, and the least-squares curve fitting. Considering the radius calculated, the compensation
controlling points can be obtained. Compared with the traditional error compensation technology, advantages of this
system include four aspects: no new error is brought due to the complete online operation; introducing a GC wheel
dresser with tilting structure and lagging-dress method can enhance the dressing accuracy; the operation is convenient,
because there is no need to make strict equal-angle measurement and to confirm zero setting; processing data through
radius constraining and filtering can reach a high fitting precision, which is useful to the compensation machining later.
Keywords: online dressing, online measuring, filtering, least squares method
Design of an optical lens for a space tridimensional mapping camera
Author(s):
Li-ping Zhang;
Zhi Wang
Show Abstract
Three-linear array tridimensional mapping camera consists of three independent linear CCD cameras. Unique position
must be kept among the three linear CCD cameras. Optical lens is one of pivotal parts, MTF, resolving power, distortion
are its important techno-items. The optical lens of space tridimensional mapping camera is the key to accomplish the
tridimensional mapping mission. In order to meet the need of user, a design on optical lens of transmission
semi-telecentric beam path in image space is expounded, and assembly method based on DFT(Design For Test) of single
lens suit and whole optical lens are expounded. The test results indicates that the MTF of optical lens referred in the
paper is 0.45(@77lp/mm); the ground resolution power is 5m; the distortion is 3/10000. They meet the need of user.
Effect of several processing parameters on material removal ratio in the deliquescent polishing of KDP crystals
Author(s):
Feihu Zhang;
Shaolong Guo;
Yong Zhang;
Dianrong Luan
Show Abstract
A new ultraprecision machining technology for potassium dihydrogen phosphate (KDP) crystals, deliquescent polishing
technology for KDP crystals, which utilizes deliquescent effect for ultraprecision machining KDP crystals, is proposed.
The principle and the advantages of technology are introduced. The deliquescent polishing procedure of KDP crystals is
given. The deliquescent polishing experiments of KDP crystals are conducted, and the material removal ratios are
calculated. Through the experiments, the effect of four processing parameters (velocity of polishing plate, velocity of
drip, volume percentage of water in the deliquescent polishing fluid, polishing pressure) on material removal ratio in the
deliquescent polishing of KDP crystals is researched. The plot of material removal ratio versus every processing
parameter in the deliquescent polishing of KDP crystals is obtained, and the rules of material removal ratio in the
deliquescent polishing of KDP crystals are reached.
Passive Q-switching dynamics in all-fiber lasers with ring interferometer
Author(s):
Lin Huang;
Yongzhi Liu;
Zhiyong Dai;
Qianshu Zhang
Show Abstract
The cooperation of Rayleigh scattering (RS) in fiber interference loop and stimulated Brillouin scattering (SBS) in fiber
can change Q factor in resonant cavity, based on which a all-fiber Er-doped Q-switched fiber laser with interference loop
is designed. During experiment, the attributes of output laser exploiting interference loops with different coupling ratios
and lengths is investigated. A train of pulse laser with pulse duration of 7.2ns, pulse period of 4.709μs, average
output power of 5.4mW at pump power of 37mW is obtained which has a good waveform and a peak power fluctuation
of : 30%. The results show that interference loop with too high coupling ratio has no contribution to the generation of
pulse laser and the coupling ratio of 10% is suit for it. Even if the coupling ratio of : 10% is chosen, the length of the
loop has influence to the attribute of the output laser pulse and the length around 2m is conducive to obtaining good
output.
Ultraprecision fabrication of large stamping die of Wolter mirror for an x-ray telescope by ELID grinding
Author(s):
Shaohui Yin;
Hitoshi Ohmori;
Yoshihiro Uehara;
Fengjun Chen;
Yongjian Zhu;
Yu Wang
Show Abstract
This paper presents a ultra-precision manufacturing process of large stamping dies with confocal paraboloidal and
hyperboloidal surfaces of Wolter mirror for an X-ray telescope. In order to improve the alignment of the two substrates
and reduce the degeneration in imaging quality, two compound reflectors were formed from one thin substrate utilizing
synthetic ELID grinding and arc-enveloped grinding method. Because the thin foil substrate was obtained by press
forming, large stamping dies of foil substrate must be machined with high Fig. error and low roughness. In this ELID
arc-enveloped grinding system, cast iron fiber bonded (CIFB) diamond wheels were 3-dimentional controlled to scan the
workpiece and generate required surfaces. Through truing grinding wheel and ELID grinding for upper concave and
lower convex stamping dies, attainable form accuracy, surface roughness were investigated.
End-pumped Nd:YAG Q-switched laser with high energy and narrow pulse for glass carving
Author(s):
Ming Ling;
Guang-yong Jin;
Xue-chun Tan;
Zhi-chao Wu;
Zhu Liang
Show Abstract
In order to raise the accuracy of glass carving and improve deep cutting, a novel diode end-pumed solid-state laser is
researched. Selecting proper volume of laser crytal, one continue wave laser diode which longitudinally pumped Nd:YAG
crystal is performed and an applied optics coupling system is designed with self focusing.Computing with ray trace
software and MATLAB software, the best parameter is obtained, so pumping beam is coupled efficiently to
Nd:YAG.Used a Cr4+:YAG crystal with the singnal transmission of 82% and a line plane-concave cavity, nanosecond
narrow pulse is gotten. After two thermal-electrical coolers kept the laser to work at constant temperature instead of
water cooling, the volume of laser is markedly reduced. The method of thermal-electrical cooling could increase the
system efficiency,achieve the effect of low mode output.Experimental results indicate that the maximum laser output
energy in 1064 nm is 118mJ,pulse width is 5 ns, conversion efficiency from light to light is 15.7% under the condition of
the incident power of 5 W and the diameter of the output laser spot is less than 1 mm. This end-pumped Nd:YAG
Q-switched laser with the light output of high quality and long life, which has 0.01 mm accuracy after lens focusing can
satisfy the glass carving with higher precision, rapid speed as well as easy control. It can be used in carving all kinds of
glass and replace current CO2 laser.
Design and fabrication for the diffractive optical element of an infrared system
Author(s):
Changcheng Yang;
Shenghui Li;
Yong Li;
Bin Wang
Show Abstract
A diffractive/refractive system with a relative aperture of f/4.0, the EFL of 150mm at 3.7-4.8μm is designed. A
diffractive optical element (DOE) is fabricated by means of diamond turning on a conic substrate of the Germanium
lens in this system. The characteristics of the diffractive optical element are analyzed in the software of Diffsys. And the
zone radius of DOE and step height are detected by profilometry and result is produced. Test results of DOE are
coincided with the design figures and the DOE has tiny surface error and high diffractive efficiency. Result of
Modulation Transfer Function (MTF) for the system is tested by Ealing and the tested value is closely approximate to
diffractive limit. The DOE has better behaviour of chromatic aberration and athermalization.
New simplified coupling system of 15MW Nd:YAG laser pulse with 600um optical fiber by use of a taper fiber
Author(s):
Xinyan Fan;
Jingjiao Liu
Show Abstract
Optical fiber delivery of high peak power Nd:YAG Q-switched laser pulse is required for applications such as material
processing, medical or military. The maximal transmitting power is variously limited by optical breakdown of air in the
focal point and the damage threshold of fiber. A coupling system of 600μm all-silica optical fiber fused with taper fiber
coupler and 15MW, 8ns Nd:YAG laser pulses is presented, consisting of an inversed telescope and a taper fiber coupler
without the use of a vacuum chamber. The taper fiber delivers light basing on the principle of total reflection. The
influence of incidence angle and taper length on the reflection angle are theoretic analyzed based on geometric optics.
The coupling efficiency of the 12 tapered fibers fused with 1meter fiber is measured under different incidence angle of,
respectively, 20mrad, 40mrad and 60mrad. The experiment results show that the coupling efficiency decreases gradually
with the increase of taper length for larger modal loss. The larger incidence angle also decreases the coupling efficiency,
which is consistent with above theoretic analyze. For 20mrad incidence angle, the coupling efficiency reaches as
95.53%. No surface damage or bulk damage is observed for 20meters fiber. In conclusion, the system could transmit
15MW Nd:YAG laser pulses by 600μm all-silica optical fiber stably. Intensity of 600μm fiber output surface is
4.42GW/cm2. The simplified coupling system resolves air breakdown of focal area and surface damage of fiber surface.
Study on the technique of pulse electroforming in optical manufacturing
Author(s):
Hongyou Li;
Yinbiao Guo;
Xiaomei Liu;
Tongqun Ren
Show Abstract
In this paper, bipolar pulse current electroforming is introduced. The influencing parameters, such as electrolyte
parameter, additives, current density, PH value, temperature and pulse current parameters have been studied on
experiments. Experiments on nickel electroforming in precision optical parts and moulds have been done. Results
indicate that bipolar pulse current could improve the quality and precision, reduce internal stress duringoptical
manufacturing.
High brightness white LED driver with adaptive current control strategy
Author(s):
Xin Liu;
Shuxu Guo;
Lifang Bian;
Dong Qiao;
Zhengxuan Wang;
Yuchun Chang
Show Abstract
A high efficiency and high brightness white LED driver with adaptive current control strategy in 0.5um CMOS process is
presented in this paper. The current control mode is determined by output current level and input voltage value, switching
between normal low drop-out (LDO) regulator and 2×charge-pump mode. The presented whiter LED driver is able to
drive load current as large as 1.1A. The peak efficiency as high as 95% occurs at 220mA load current, with an output
voltage ripple lower than 95mV at 1.1A output current can be achieved.
Research and design of infrared optical system based on DOE
Author(s):
Xinling Wen
Show Abstract
The infrared optical system is an important part of an infrared detection system. With the keeping upgrading of infrared
detectors and requirements for infrared detection systems based on a variety of applications, higher requirements for
infrared optical systems have been put forward in terms of performance and designing optimization. Based on infrared
option system and DOE theory, the effects of environment temperature on optical systems are analyzed. This paper
introduces DOE theory, aberration and color difference characteristic, etc. Refractive-diffractive mixed system is carried
out by using DOE to infrared optical system, which results in high quality and simple optical system. The image quality
of the optical systems is eva1uated by making use of modu1ation transfer function (MTF). A performance comparison is
done between conventional refractive optical system and hybrid optical system, showing that hybrid optical system has
obvious advantages in terms of image quality, volume, weight, environmental adaptability over traditional refractive
optical system.
Design of a CAN bus interface for photoelectric encoder in the spaceflight camera
Author(s):
Ying Sun;
Qiu-hua Wan;
Rong-hong She;
Chang-hai Zhao;
Yong Jiang
Show Abstract
In order to make photoelectric encoder usable in a spaceflight camera which adopts CAN bus as the communication
method, CAN bus interface of the photoelectric encoder is designed in this paper. CAN bus interface hardware circuit of
photoelectric encoder consists of CAN bus controller SJA 1000, CAN bus transceiver TJA1050 and singlechip. CAN bus
interface controlling software program is completed in C language. A ten-meter shield twisted pair line is used as the
transmission medium in the spaceflight camera, and speed rate is 600kbps.The experiments show that: the photoelectric
encoder with CAN bus interface which has the advantages of more reliability, real-time, transfer rate and transfer
distance overcomes communication line's shortcomings of classical photoelectric encoder system. The system works
well in automatic measuring and controlling system.
Design on visible diffractive-refractive hybrid collimator
Author(s):
Xu-hua Zhai;
Hong-tao Zhang;
Hai-shan Zhao;
Hai-feng Xu;
Zhou Qu
Show Abstract
Collimator is an important equipment with high accuracy in optical experiment and measuement. In order to improve
measuring accuracy, based on the particular aberration property of diffraction optical element, hybrid refractivediffractive
aberration correction method is put forward. In this paper, a hybrid refractive-diffractive method is compared
with conventional method with 80mm diameter, 500mm focal length and 550mm overall length. The resolution is less
than 4.3". Having been optimized, the maximum spot is 5.2μm, and the modulation transfer function (MTF) at
50lp/mm is over 0.8, better than conventional method.
Three-dimensional thermal analysis for laser assisted machining of ceramics using FEA
Author(s):
Xuefeng Wu;
Hongzhi Zhang;
Yang Wang
Show Abstract
Laser-assisted machining (LAM) is an effective method machining difficult-to-machine materials such as ceramics which
uses a high power laser to focally heat a workpiece prior to material removal with a traditional cutting tool. To understand
the thermal process of laser heating and predict the operation parameters for experiment system, a transient,
three-dimensional heat transfer model for LAM of silicon nitride is developed using Finite Element Method. The model is
based on temperature-dependent thermophysical properties and considering convective heat transfer and radiation
exchange. A method of locally refining mesh according to machining sequence is used to reduce calculating time. The
effects of the operating parameters, such as laser power, laser beam diameter, laser preheat time, cutting depth, feed rate
and rotational speed on the average temperature of cutting region and the temperature of laser incidence are investigated.
The thermal stresses induced from the high temperature gradient are also investigated. The maximum normal thermal
stress failure criterion is used to predict the possibility of cracking on silicon nitride material owing to thermal stress. The
method of selecting optimizing operation parameters is presented.
Correction capability analysis and experimental validation of a kind of adaptive optics system based on a combined deformable mirror for compensating high-order aberrations
Author(s):
HuaFeng Yang;
ChangHui Rao;
WenHan Jiang
Show Abstract
A kind of new adaptive optics (AO) configuration, for which several deformable mirrors (DMs) with optical conjugation
relationships are combined to correct high-order aberrations, is proposed. Based on theoretical analysis and numerical
simulation, an integrated AO system with combinational-deformable-mirror (CDM) that consisted of two same
deformable mirrors is built, and its correction capability is validated experimentally. The results indicate that the CDM in
the AO system correct aberrations effectively as same as one single DM with more actuators by using the direct-gradient
control algorithm in closed-loop. This design can improve wavefront spatial correction capability by increasing the
number of actuators and the coupling coefficient. So it can be used for compensating high-order aberrations instead of
one single costly DM with more actuators for the same performance.
ITO glass polishing using carbon dioxide snow jet technique for organic light-emitting diodes
Author(s):
Junjian Li;
Tong Li
Show Abstract
Surface roughness of indium-tin-oxide (ITO) film plays a crucial role on the performance of organic lighting emitting
devices (OLEDs). A set of polishing apparatus with carbon dioxide snow jet as an actuating medium is established, and
the surface polishing of ITO glass are carried out by this equipment. The surface morphology of ITO film is measured by
using an atomic force microscope (AFM) before and after polishing treatment. The results show that before polishing,
the mean values of Ra, Rpv and the RMS of the ITO surface are 1.463, 46.87 and 2.726 nm, respectively. After polishing,
the value decreases to 0.773 nm, 19.51 and 1.078nm. It indicates that the polishing method is effective to reduce the ITO
surface roughness. Another merit of this polishing method is that the polishing process has a cleaning effect to the ITO
glass surface The performance of OLED can be enhanced and the production cost of device can be reduced.
Compositional dependence of absorption edges in evaporated Pb1-xGeTe thin films as infrared short-wavelength cutoff filters
Author(s):
Bin Li;
Suying Zhang;
Ping Xie;
Dingquan Liu
Show Abstract
Semiconductors which exhibit a very rapid transition from opacity to transparency at the intrinsic edge are particularly
useful in making excellent absorption filters. In this paper, we report the investigation on composition dependence of
absorption edges in the evaporated Pb1-xGexTe thin films, which will be of a potentiality to fabricate a single-layer
infrared short-wavelength cutoff filter by means of controlling the composition and processes. It is revealed that for
thin films with an identical Te concentration, the absorption edges will shift towards short-wavelength with the increase
of Ge concentration x in films; whereas, for those with a similar Ge concentration within a small range of deviation, the
edges will also shift towards the short-wavelength with Te concentration approach to stoichiometry.ÿÿ
Research on antireflection characteristic of rectangular subwavelength surface-relief structure
Author(s):
Weimin Tan;
Chun-hua Lu;
Zhongzi Xu;
Yaru Ni
Show Abstract
In this paper, using effective-medium theory (EMT) and finite different time domain (FDTD), the dependence of
reflectivity to 1.06 μm incident light upon structural parameters of rectangular subwavelength surface-relief structure has
been discussed, the reliability of FDTD has been proved, and the validity of the two theories has been contrasted. The
influence of refractive index and filled factor to reflectivity has been analyzed detailedly. And the structural parameters
also have been discussed by diffraction orders in the energy field of reflective area with FDTD. The results shows that
the best filled factor is near 0.7, the structure periods should less than 0.6λ, and the structure thickness would be set to
λ/4neff. It can be used as the basis for design and fabrication of surface structural materials with proper antireflection
property.
Study on the methods for ensuring the precision of an x-ray microscope
Author(s):
Lingling Zhao;
Delin Sun;
Peng Liu;
Jiasheng Hu
Show Abstract
In the latest 20 years, x-ray imaging technology has developed fast in order to meet the need of x-ray photo-etching,
spatial exploration technology, high-energy physics, procedure diagnosis of inertial confinement fusion (ICF) etc. Since
refractive index of materials in the x-ray region is lower than 1, and x-ray is strongly absorbed by materials, it is very
difficult to image objects in the x-ray region. Conventional imaging methods are hardly suitable to x-ray range. In
general, grazing reflective imaging and coding aperture imaging methods have been adopted more and more. In order to
ensure the tolerances of KBA, we take many measures to ensure the high requirements during the installation and
adjustment process.
Simulation of substrate temperature in HFCVD diamond thin films
Author(s):
Yongjie Wang;
Huijuan Wang;
Zengqian Yin
Show Abstract
The substrate temperature is one of the most important parameters for the synthesis of high quality diamond thin films in
hot filament chemical vapor deposition (HFCVD) system. Based on the principle of heat transfer, the substrate
temperature is calculated in the single hot filament system, the influence of filament height, filament diameter and
filament length on substrate temperature are also discussed. Results show that the substrate temperatures vary with the
space position. In the direction of parallel with the filament, the substrate temperatures vary smoothly, but, in the vertical
direction of the filament, the substrate temperatures change acutely. When H=8mm, L=7cm and df=0.5mm, the substrate
temperatures are well-distributed, this will give the support of some technique parameters for the growth of large area
HFCVD diamond thin films.
Design of an erbium-doped fiber laser based on ring cavity
Author(s):
Huawei Pang;
Hua Lian;
Ruimei Zhao;
Tianshan Liu;
Boning Hu;
Huimin Cui;
Yafang Wang
Show Abstract
Erbium-doped fiber laser has many excellences, such as narrow bandwidth and long range to tune. It could be used in
DWDM communication and sensing. We focuse on erbium-doped fiber laser, because it radiates at 1550nm lying in 3 rd
window of low loss in fiber-optic communications. In this paper, by studying erbium-doped fiber ring laser's theory and
using simulation method, we have obtained many key laser parameters, and designed a high efficiency erbium-doped
fiber ring laser with a fiber Bragg grating used as filter .When the pump power is 150mW, a ring-cavity all-fiber laser
worked at 1550.285 nm has been demonstrated with an output power of 45 mW and a bandwidth of 0.05 nm at 3dB. Its
pumping efficiency is 30%. In the design, we have adopted many kinds of methods to stabilize its power. Finally the
power stability is 0.20%. Such laser is suitable for communications and sensing.
Pressure distribution model in edge effect
Author(s):
Yu Han;
Fan Wu;
Yong Jian Wan
Show Abstract
For better explain the phenomena of edge effect, a Constant-Linear pressure distribution model is presented in this paper
according to a series of computer simulations. The limitations of the existing models are analyzed. Experimental results
show that the C-L model can correctly predict the material removal near border of work-piece.
Raman active phonons in RMnO3 (R=La, Pr, Nd, Sm) manganites
Author(s):
Wei-Ran Wang;
Geng-Xin Song;
Yan Zhao;
Xue-Ying Han
Show Abstract
RMnO3 (R=La, Pr, Nd, Sm) Manganites prepared using solid-state reaction method were examined by Raman
spectroscopy. Raman-active phonons in orthorhombic perovskitelike RMnO3 were studied by measuring Raman spectra
in various scattering configurations. The experimental Raman line wave numbers and the expected shapes for the phonon
modes were compared to those reported for other perovskitelike compounds with Pnma structure and to the results of
lattice dynamical calculations. The observed Raman lines in the spectra of RMnO3 were assigned to definite atomic
motions. The remaining spectral weight can be explained by the presence of dynamic John-Teller distortions that lower
the symmetry of the cubic perovskite. It is clear that Raman spectroscopy has the advantage of being very sensitive to
structure distortion and oxygen motion.
Cascaded chirped and phase-only sampled fiber Bragg gratings for efficient comb filters
Author(s):
Xiaojun Zhu;
Yuling Lu;
Chinhua Wang
Show Abstract
Cascaded chirped and phase-only sampled fiber Bragg gratings (CC-PSFBGs) are proposed for high efficient
multi-channel comb filters in wavelength-division multiplexing (WDM) systems. A CC-PSFBG consists of replicated
sections of chirped and phase-only sampled FBGs, in which the Talbot conditions for each section of phase-only
sampled FBGs are satisfied. Under the condition of phase matching among the cascaded sections, an arbitrarily tunable
channel spacing (tunable free spectral range, FSR) with both a controllable wavelength range and sufficient in-band
energy efficiency can be implemented. It offers a useful tool for improving the design flexibility and the energy
efficiency of conventional Talbot effect based multichannel comb filters.
Roughness evolution of fused silica during plasma polishing processes
Author(s):
Weiguo Liu;
Dasen Wang;
Minda Hu;
Yingnan Wang;
Haifeng Liang;
Lingxia Hang
Show Abstract
Plasma polishing process finds important applications in the fabrication of super-smooth optical surfaces. It can be
applied for the precise optical surface forming and to obtain optical surfaces with ultra-low roughness and without
sub-surface damage (SSD). Published results show that the plasma polishing process is mainly used for the precise
optical surface forming. Very limited results are reported in literatures on the process being used for the reducing of the
optical surface roughness. A novel plasma polishing process has been developed in the Laboratory of Thin Film
Techniques and Optical Test in Xi'an Technological University. In the process, highly stable SF6 and Ar plasmas are
generated by using capacitive coupled hollow cathode (CCHC) RF discharge method. Factors that affect the stability of
the plasma, such as gas flow rate, pressure and discharge power are systematically investigated. The polishing processes
of fused silica have been studied using CCHC RF plasma. When the process parameters of the gas flow, pressure, and
plasma powerare optimized, the roughness of the silica surface can be reduced from 1.2nm to 1.0nm in rms with
minimized SSD.
Study on deposition of amorphous hydrogenate DLC films on germanium substrates by RF-PECVD
Author(s):
Ji-long Tang;
Guo-jun Liu;
Jing Wang;
Zhi-chao Wu;
Ying-jie Zhao;
Xiu-hua Fu
Show Abstract
This paper aims to research the influence of hydrogen on the variation of mechanical properties and microstructure of
diamond-like carbon (DLC) films synthesized by radio frequency plasma chemical vapor deposition (RF-PECVD). The
DLC films were deposited on germanium substrates as protective layers with butane-hydrogen mixture gas. The films
obtained are polycrystalline and texture-growth, the surface of the thin films is grain-like and dispersing incompact. The
synthesis and post-plasma etching treatment of DLC films were prepared with low-temperature methods (T<150°C). The
reactant gas is a high pure mixture of butane (99.9%) and hydrogen (99.99%). The effect of deposition parameters on the
structure and properties of DLC thin films has been studied.
DLC films deposited are studied by atomic force microscopy (AFM), Raman, Fourier-transform infrared (FTIR),
nanoindentation and nanoscratch. Test results show the transmissivity of deposited DLC films from 8μm and 12μm
region is higher than 60% averagely, which closees to theory value firstly. Secondly, with the increase of deposition
voltage, the content of sp3C in the DLC thin films increases, the roughness of thin films decreases. Thirdly, with the
increase of deposition frequency, the content of sp3C in the DLC thin films increases, the roughness of the thin films
decreases. Finally, as the film thickness increases, the ratio of I(D)/I(G) increases and the hardness decreases. This
indicates as the film thickness increases, the bonding is towards graphite structure and reducing hardness. The high sp2
fraction and low hardness explain the poor adhesion of large film thickness. The results reveal that increasing the
concentration of hydrogen, thickness and roughness decreases.
Fabrication and characteristics of polarization maintaining polymer photonic crystal fiber with elliptical core
Author(s):
Yani Zhang
Show Abstract
A novel structure of highly birefringent polarization maintaining photonic crystal fiber is designed theoretically, the fiber
has an elliptical core and five ring square hexagonal structure, with the average hole-diameter, d=2.5μm, and the ratio of
average hole-diameter and hole-spacing d/Λ=0.4. The polarization mode field and birefringence are numerically
simulated by Beam propagation method based on full vector model. Research results showes that two orthogonal
polarized states of the fundamental mode become non-degenerate in the elliptical core PCFs and appear obviously an
ellipse and strongly linear polarization. Furthermore, we firstly fabricated successfully the fiber with near elliptical core
based on organic macromolecule polymer material by in-situ chemical polymerization technology and the secondary
draw-stretching of the preforms. The polarization mode fields and transmission loss are measured, and the results are
well accorded with theory, which will be promising to fabricate high birefringence polarization maintaining photonic
crystal fiber based on polymer for applications in data communication networks and for the development of range of new
polymer-based polarization maintaining fibers components.
Double grating monochromator optical design of the pure rotational Raman-lidar
Author(s):
Zhen Zhang;
Fang Liu
Show Abstract
The temperature of troposphere is an important meteorologic parameter, the pure rotational Raman-lidar technique has
already used on effective temperature-measuring of troposphere at present. Because many low-intensity scattering is
around high-intensity scattering, it is difficult to acquire Raman spectrum from high-intensity Mie+ Rayleigh scattering.
So the prismatic system needs reach high capability. The double grating monochromator for a pure rotational Ramanlidar
can provide better than 10-7 suppression of spectral line due to unshifted Mie+ Rayleigh scattering, obtain highpurity
rotational Raman spectrum, and improve transmission and stability of the optical system. The complex structure of
the double grating monochromator is always difficult to Raman-lidar. Two optical paths of grating are compared and a
conclusion can be drawn that the structure of beam path of grating of symmetrical arrange of optical fibre is better in
grating efficiency than the structure of beam path of grating of linear arrange of optical fiber. Then a formula about
relative of range of diffractive angle and order of grating is obtained through grating equation and rotational Raman
equation. When grating constant is 600 line/mm, the fifth order of grating is optimal. According to these, we can
optimize the double grating monochromator from the paths of grating and parameter of grating and improve transmission
and stability of lidar temperature-measuring system, make the whole lidar system higher Signal-to-Noise, and attain
more exact atmosphere outline.
Method for signal detection of integrated optic gyroscope based on digital signal processing
Author(s):
Zhen Zhang;
Xin Yin;
Cheng Cheng
Show Abstract
The integrated optic gyroscope (IOG) has many advantages, such as small volume, light quality, low propagation loss,
vibration-resisting and high stability, which is the development direction of high-precision and miniaturized optic
gyroscope. The result of signal detection influences the precision and detecting sensitivity of IOG directly. Noise is the
crucial factor to limit detecting precision. In the practical application, the output signal of IOG is mixed up with many
sorts of noise, which interferes the detection of useful message and lead drift and instability of output signal of
gyroscope. So increasing the precision and detecting sensitivity directly of IOG needs not only suppressing the noise
origin, but also detecting the signal in noise with effective method. According to the characteristics of output signal from
detector, a signal processing method for IOG is introduced, which detects signal from noise by taking advantage of
digital filter and cross-correlation, based on a digital system comprised of a high-performance digital signal processor.
The result of experiments shows that percent error is less than 3 percentage or large under condition of 10 dB signal-tonoise
ratio. The information of rotation in IOG is extracted effectively from the output signal mixed up with noise by this
method.
Low side bands wide spectrum width femtosecond passively mode-locked fiber laser
Author(s):
Yu Zhao;
Yongzhi Liu;
Deshuang Zhao;
Lin Huang;
Zhiyong Dai
Show Abstract
Femtosecond (fs) fiber laser is very useful in fiber sensor and OTDM optical soliton communication systems. To study
the suppression of side bands and the broadening of spectrum width in fs fiber laser, passively mode-locked fiber ring
laser were experimentally studied. This study was based on side bands generation principle and nonlinear polarization
rotation (NPR) mode lock principle. 3m deeply doped fiber was used in the ring of NPR fiber laser in the experiments, so
that there were enough group velocity dispersion (GVD), chirp and high-level nonlinear effects in the ring. And these
effects would help suppressing side bands and broadening spectrum width. The fiber laser with low side bands, spectrum
width of 25.4nm, spectrum width tuning range of 12.4nm and repetition rates of 15.8MHz was gotten in the experiments.
The theoretical limiting pulse width was about 300fs and the pulse amplitude had gotten 4% fluctuation.
Lasing behavior in cascade energy transfer in dual-doped polymer microcavities
Author(s):
Xuan-ke Zhao;
Qing-hua Zhang;
Qing-wu Zhao;
Lian-fen Wang
Show Abstract
We have studied a cascade energy transfer based on the long-range dipole-dipole Forster energy transfer between
polymer and two fluorescent dyes in surface emitting microcavities, which is formed by sandwiching a
poly(N-vinylcarzole) (PVK) film doped with 8-trishydroxyquinoline (Alq3) and 4-(dicyanomethylene)-2-tert-butyl-6 (1,
1, 7, 7-tet ramethyljulolidyl-9-enyl)-4H-pyran(DCJTB) between a distributed Bragg reflector (DBR)(with a reflectivity
of 99%) and a silver film (which depth is 140nm). The sample was optically pumped by a frequency-tripled Nd:YAG
laser (Continuum Surelite I) delivering 5.55ns pulses at 355nm with a 10Hz repetition rate. By optimizing the
concentrations of Alq3 and DCJTB in PVK, a low lasing threshold of about 9.62ΜJ per pulse attributed to efficient
cascade Forster energy transfer form PVK and Alq3 to DCJTB was obtained. The full width at half maximum (FWHM)
of the emission was 3nm with the peak wavelength at 630nm. Our results demonstrate that the PVK:Alq3:DCJTB could
be a promising candidate as gain medium for red organic diode lasers.
New architectures for high-performance organic solar cell introducing phosphorescent iridium complex
Author(s):
Hui Lin;
Junsheng Yu;
Wei Zhang;
Shuangling Lou;
Yadong Jiang
Show Abstract
In this work, We report on highly efficient organic solar cells based on bis[2-(4-tertbutylphenyl) benzothiazolato-N, C2,]
iridium (acetylacetonate) [(t-bt)2Ir(acac)], a material that has been investigated as dopants in organic light-emitting
devices (OLEDs). Organic device with structure of indium tin oxide (ITO)/(t-bt)2Ir(acac):CuPc/C60/BCP/Ag, is
fabricated. By doping (t-bt)2Ir(acac) into standard CuPc/C60 OPV cell, a high JSC of 8.23 mA/cm2, VOC of 0.36 V, and an
exceptionally high power conversion efficiency of 1.42% are achieved. The performance improvement is mainly
attributed to efficient light absorption by (t-bt)2Ir(acac) in the range of 380-500 nm, leading to more effective exciton
dissociation. Their findings motivate the use of phosphorescent dyes for increasing photon harvesting as well as charge
transfer efficiency.
High-quality silicon nitride films prepared by low-frequency plasma-enhanced chemical vapor deposition
Author(s):
Huile Zhang;
Xiangdong Xu;
Yuping Leng;
Weizhi Li;
Zhiming Wu;
Yadong Jiang
Show Abstract
With their excellent mechanical, thermal, and optical properties, silicon nitride (SiNx) films are widely used as both
supporting and insulating materials for MEMS structures. Practical applications of SiNx films rely on their film quality,
which will affect the performance and stability of the related devices. In general, SiNx films are deposited by low
pressure chemical vapor deposition (LPCVD) or high-frequency (13.56 MHz) plasma-enhanced chemical vapor
deposition (HF-PECVD). However, up to now, less reports about the deposition of SiNx films by low-frequency
plasma-enhanced chemical vapor deposition (LF-PECVD) have been made. This paper reports the preparation of SiNx
thin films by PECVD with a low frequency (380 kHz). The process parameters were carefully optimized for the growth
of SiNx films. And the thicknesses and refractive indices of SiNx films were characterized by spectroscopic
ellipsometry with small mean square error (MSE<2.5) using Tauc-Lorentz fitting model. It was revealed that the
thickness uniformity, deposition rate, and wet etching rate of the as-prepared SiNx films strongly depend on the key
process parameters, including RF frequency, power, gas flow ratio, deposition temperature and pressure. Our results
also indicated that the refractive index of SiNx film can be rationally tuned to be 1.874 ~ 2.145 by LF-PECVD.
Moreover, the wet etching rate of SiNx film in a diluted HF solution can be controlled to be 7.4 to 65.9 nm/min, and the
deposition rate ranges from 23.5 to 260.8 nm/min. We also experimentally confirmed that the SiNx thin films deposited
with low frequency (380 kHz) exhibit better thickness uniformity, higher deposition rate and lower wet etching rate,
compared with those deposited with high frequency (13.56 MHz). Particularly, 150-mm-diameter SiNx thin films with
high thickness uniformity (thickness nonuniformity <1.0%) were successfully produced in this work. With their
tunable physical properties, the LF-PECVD SiNx thin films exhibit great potential in microelectronics and
optoelectronics applications. Moreover, the SiNx films prepared by LF-PECVD are compared with those produced by
HF-PECVD and DF-PECVD.
Novel low area CMOS readout circuit for uncooled microbolometers with low noise
Author(s):
Jian Lv;
Yadong Jiang;
Yun Zhou;
Fengwu Luo
Show Abstract
We propose a novel CMOS readout structure without sample and hold (SH) circuit for uncooled microbolometers. In this
readout circuit, all the pixels in one row can be integrated simultaneously, and the readout integrated circuit (ROIC) area
can be reduced by as much as 30%. Moreover, a single capacitor implementation of both capacitive transimpedance
amplifier (CTIA) and correlated double sampling (CDS) is utilized to improve noise performance. An experimental
40x30 ROIC chip has been designed and fabricated with 0.5 μm CMOS technology. The test results show that the ROIC
has good linearity with 260μV RMS total output noise voltage and 1800x650 μm2 total circuit area.
High-efficiency blue organic light-emitting devices based on phosphorescent dopant material
Author(s):
Jiang Zhong;
Yadong Jiang;
Lei Zhang;
Junsheng Yu
Show Abstract
A novel kind of multilayer blue electrophosphorescent organic light-emitting diode (PHOLED) is developed via vacuum
thermal deposition method. Host and dopant materials are co-deposited to fabricate as an emissive layer (EML) in one
vacuum chamber. The (tpbi)2Ir(acac) as dopant material is synthesized based on noble metal element iridium. The film
thickness of each layer is in situ controlled with a quartz crystal microbalance. The typical device structure is ITO/CuPc
(30nm)/NPB (40nm)/TPBi(30nm):(tpbi)2Ir(acac) (X wt%)/Alq3 (20nm)/LiF (1nm)/Al (100nm), where X wt% stands for
the doping concentration ranging from 1 to 4 wt%. Optoelectronic characteristics including current, bias voltage,
brightness, efficiency and spectrum of the devices is characterized. The results showed that the current of the device
under low applied voltage is consistent with the Richaardon-Schotty emission, and has linear relationship under different
voltages. When X wt% is 3 wt%, a maximum luminance efficiency of the PHOLED of 5.37lm/W with a luminance of
317cd/m2 at 7.0V is obtained. When the driving voltage is 15 V, the brightness of the device reached to 7,827 cd/m2,
corresponding to the CIE coordinates of x=0.142, y=0.217.
Color-tunable organic light emitting diodes based on exciplex emission
Author(s):
Junsheng Yu;
Shuangling Lou;
Wen Wen;
Yadong Jiang;
Qing Zhang
Show Abstract
A fluorene derivative of 2,3-bis(9,9-dihexyl-9H-fluoren-2-yl)quinoxaline (BFLYQ) with blue fluorescence peaking at
425 nm is synthesized. The blend film of BFLYQ and N,N'-di(naphthalen-2-yl)-N,N'-diphenyl-benzine (NPB) exhibited
an additional bathochromic shifted and broadbanded emission at 513 nm besides blue light in photoluminescence (PL)
spectrum. The bilayer device with a structure of indium-tin-oxide (ITO)/NPB (40 nm)/BFLYQ (40 nm)/Mg : Ag showed
a low-energy emission peaking at green area in electroluminescent (EL) spectra, which is due to exciplex emission
between NPB and BFLYQ molecules, and the blue emission from BFLYQ increased with the enhancement of bias
voltage. Based on exciplex emission, using
4-(dicyanomethylene)-2-t-butyl-6-(1,1,7,7-tetramethyljulolidyl-9-enyl)-4H-pyran (DCJTB) as red dye, the color-tunable
organic light-emitting diodes (OLEDs) are fabricated by conventional thermal vacuum deposition. The devices showed
emission from red to white light with increasing the distance of DCJTB and the interface of NPB/BFLYQ. Also, the
luminescent mechanism of DCJTB is discussed.
Organic thin film transistor with a simplified planar structure
Author(s):
Lei Zhang;
Jungsheng Yu;
Jian Zhong;
Yadong Jiang
Show Abstract
Organic thin film transistor (OTFT) with a simplified planar structure is described. The gate electrode and the
source/drain electrodes of OTFT are processed in one planar structure. And these three electrodes are deposited on the
glass substrate by DC sputtering technology using Cr/Ni target. Then the electrode layouts of different width length ratio
are made by photolithography technology at the same time. Only one step of deposition and one step of photolithography
is needed while conventional process takes at least two steps of deposition and two steps of photolithography. Metal is
first prepared on the other side of glass substrate and electrode is formed by photolithography. Then source/drain
electrode is prepared by deposition and photolithography on the side with the insulation layer. Compared to conventional
process of OTFTs, the process in this work is simplified. After three electrodes prepared, the insulation layer is made by
spin coating method. The organic material of polyimide is used as the insulation layer. A small molecular material of
pentacene is evaporated on the insulation layer using vacuum deposition as the active layer. The process of OTFTs needs
only three steps totally. A semi-auto probe stage is used to connect the three electrodes and the probe of the test
instrument. A charge carrier mobility of 0.3 cm2 /V s, is obtained from OTFTs on glass substrates with and on/off current
ratio of 105. The OTFTs with the planar structure using simplified process can simplify the device process and reduce the
fabrication cost.
Concentration effect of dye dopant in organic light emitting diodes
Author(s):
Lu Li;
Junsheng Yu;
Shuangling Lou;
Yadong Jiang
Show Abstract
The influence of concentration effect of fluorescent dye dopant 5,6,11,12-tetraphenylnaphthacene (Rubrene) molecules
on the performance of small organic light-emitting diodes (OLEDs) has been investigated. An ultrathin dye layer is
deposited at the interface of host material via thermal vacuum deposition, dopant concentration is enhanced and the
effect of concentration quenching is more obvious. Also, the photoluminescence (PL) spectra of Rubrene solution are
provided to focus on concentration quenching. The devices have doping layer and ultrathin layer are compared via their
optoelectronic performance. It has been found from the electroluminescence (EL) spectra of the devices that the
concentration quenching effect of the doping dyes could be modulated through varying the thickness of ultrathin dye
layer.
Organic light emitting devices based on two novel silole derivatives
Author(s):
Qing Li;
Junsheng Yu;
Lu Li;
Yadong Jiang;
Xiaowei Zhan
Show Abstract
High performance organic light-emitting devices using two silole derivatives of 2,2,3,3-4,4-bisthienylsilole (TPBTSi)
and 2,2,4,4-tetraphenyl-3,3-Bisthienylsilole (TPB3TSi) as emitting materials are fabricated by vacuum thermal
evaporation method. N, N'-diphenyl-N,N'-bis (3-methylphenyl)-1,1'-biphenyl-4,4'-diamine (NPB) and
tris(8-hydroxyquinolinolato) aluminum (Alq3) are used as hole transporting layer (HTL) and electron transporting layer
(ETL), respectively. The luminance-voltage and current density-voltage characteristics of two devices are investigated,
and the performance difference is discussed. The results demonstrate that at a bias voltage of 16 V, the devices
consisting of novel emissive materials of TPBTSi and TPB3TSi have a maximum luminance of 11290 and 7508 cd/m2,
and the peaks of electroluminescence (EL) spectra locate at 516 and 580 nm, respectively.
White organic light emitting diodes based on a novel starburst fluorene derivative
Author(s):
Shuangling Lou;
Junsheng Yu;
Wen Wen;
Yadong Jiang;
Qing Zhang
Show Abstract
White organic light-emitting diodes (WOLEDs) are fabricated by thermal vacuum deposition method based on a novel
starburst fluorene derivative of 1,2,3,4,5,6-hexakis(9,9-diethyl-9H-fluoren-2-yl) benzene (HKEthFLYPh). The
photoluminescent (PL) spectrum of the HKEthFLYPh peaks at 374 nm, which overlapped with the absorption spectra of
N,N'-di(naphthalen-2-yl)-N,N'-diphenyl-benzine (NPB), tris(8-hydroxyquinolinato)aluminum (Alq) and
5,6,11,12-tetraphenylnaphthacene (Rubrene) materials. And PL spectra of HKEthFLYPh : NPB, HKEthFLYPh : Alq and
HKEthFLYPh : Rubrene blend in chloroform solution showed characteristics of NPB, Alq and Rubrene. Using
HKEthFLYPh as energy transfer layer, NPB as a hole transporting and blue light-emitting layer, Rubrene as a yellow
emissive layer, and Alq as an electron transporter, WOLEDs with a undoped structure are fabricated. The structure of
WOLEDs are indium-tin-oxide (ITO)/NPB (40-x nm)/HKEthFLYPh (4 nm)/NPB (x nm)/Rubrene (1 nm)/Alq (40
nm)/Mg : Ag (200 nm). The results demonstrated that when x=0 nm the device showed a yellowish white light with the
Commission Internationale de l'Eclairage chromaticity (CIE) coordinates changing from (x=0.37, y=0.40) to (x=0.34,
y=0.37) under bias voltage from 4 to 10 V; when x=5 nm the device exhibited a pure white light emission with CIE
coordinates changing from (x=0.32, y=0.30) to (x=0.34, y=0.34) under bias voltage from 4 to 10 V. Also, the pure white
device had a turn-on voltage (defined as the bias required to produce a measurable luminance of 1 cd/m2) of 3.8 V, a
luminance of 1137 cd/cm2 at a bias voltage of 15 V, and a maximum luminance efficiency of 0.51 lm/W at 4.25 V.
Electroplex light emission based on BCP and a novel star-shaped hexafluorenylbenzene
Author(s):
Tao Ma;
Junsheng Yu;
Shuangling Lou;
Yadong Jiang;
Qing Zhang
Show Abstract
Organic light emitting diode (OLEDs) are fabricated using a novel star-shaped hexafluorenylbenzene with a simple
structure of indium-tin-oxide (ITO)/1,2,3,4,5,6-hexakis(9,9-diethyl-9H-fluoren-2-yl)benzene (HKEthFLYPh):N,
N'-bis-(1-naphthyl)-N,N'-diphenyl-(1,1'-biphenyl)-4,4'-diamine (NPB)/2,9-dimenthyl-4,7-diphenyl-1,10-phenanthroline
(BCP)/tris(8-hydroxyquinoline) aluminum (Alq3)/Mg:Ag by spin coating method. The electroluminescent properties of
the device are characterized. The results show that there is a new peak at 600 nm, which is no appearance in PL spectra.
This new emission is proposed to be electroplex that occurred at the solid-state interface between HKEthFLYPh and
BCP in addition to the exciton emission from NPB. The Commissions Internationale De L'Eclairage (CIE) coordinates
of the device are (x=0.33, y=0.29) at 10 V, which obviously belongs to white light emission.
Electrical characteristics of phosphorescent organic light emitting devices with various emissive film thickness
Author(s):
Tao Wang;
Junsheng Yu;
Jun Wang;
Lu Li;
Yadong Jiang
Show Abstract
Multilayer organic light-emitting diodes are fabricated with a structure of
ITO/CuPc/NPB/CBP:(t-bt)2Ir(acac)/BCP/Alq/LiF:Al, and the current density vs voltage characteristic of organic
phosphorescent devices is investigated. The current density characteristics of triple-layer devices with different emission
layer thickness is simulated into three regions, which are no-emission region, emission region and saturated region,
corresponding to ohmic contact model, trap charge limited current model and space charge limited current model. The
film thickness of emission layer shows obvious effect on the device current density.
Study on charge carrier recombination zone with ultrathin rubrene layer as probe
Author(s):
Wen Wen;
Jungsheng Yu;
Yi Li;
Lu Li;
Yadong Jiang
Show Abstract
The characteristic of charge carrier recombination zone in
N,N'-bis-(1-naphthyl)-N,N'-biphenyl-1,1'-biphenyl-4,4'-diamine (NPB) based OLEDs is studied using an ultrathin
5,6,11,12-tetraphenylnaphthacene (rubrene) as a probe. By adjusting the rubrene thickness and location in NPB
light-emitting layer, the luminescent spectra and electrical properties of the devices are investigated. The results show
that when the thickness ranges from 0.2 to 0.8 nm, the surface morphology of rubrene exists as the discontinuous
island-like state locating on the surface of NPB film and seldom affect the electrical characteristics. While the location of
rubrene shifted from the interface of NPB/2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) to NPB side, the
maximum exciton concentration is found within 2 nm away from the interface, which is the main charge carrier
recombination zone. With an optimized structure of indium-tin-oxide (ITO)/NPB (40nm)/rubrene (0.3nm)/NPB
(7nm)/BCP (30nm)/Mg:Ag, the device exhibits a turn on voltage as low as 3 V and stable white light. The peaks of EL
spectra are located at 431 and 555 nm corresponding to the Commissions Internationale De L'Eclairage (CIE)
coordinates of (0.32, 0.32), which are relatively stable under the bias voltage from 5 to 15 V. A maximum luminance of
5630 cd/m2 and a maximum power efficiency of 0.6 lm/W is achieved. The balanced spectra are attributed to the stable
confining of charge carriers and exciton by the thin emitting layers.
Preparation and characterization of polyaniline/indium(III) oxide (PANi/In2O3) nanocomposite thin film
Author(s):
Xiaolei Yan;
Guangzhong Xie;
Xiaosong Du;
Huiling Tai;
Yadong Jiang
Show Abstract
In the last few decades, conductive polymers such as polyaniline, polypyrrole, and polythiophene have been widely
investigated as effective sensitive materials for chemical gas sensors. Among them, polyaniline (PANI) is frequently
used because of its ease and cheap of synthesis, environmental stability and intrinsic redox reaction. However, problems
with these conductive polymers include their low processing ability, poor mechanical strength and chemical stability.
There are tremendous approaches for the enhancement of mechanical strength and chemical stability of organic materials
by combining organic materials with inorganic counterparts in nano-size to form composite materials..which would
optimize the characteristics of gas sensors. In the paper, polyaniline/Indium(III) Oxide(PANi/In2O3) nanocomposite thin
films was prepared on a quartz substrate by combination techniques of electrostatic self-assembly and in situ chemical
oxidation polymerization at 10°C. Infrared spectrum analysis (IR) of the composite and scanning electron
microscope(SEM) of nanocomposite thin films were performed. PANi/In2O3 nanocomposite thin film gas sensor was
fabricated on AT-Cut quartz crystal microbalance(QCM) of Ag electrodes, and the sensitive properties of gas sensor to
CH4 and CO are characterized and analyzed. The results indicate that PANi/In2O3 thin film gas sensor has good linear
sensitive property to CH4 and CO, and is more sensitive to CH4, i.e., the sensitivity is 0.386Hz per ppm when the sensor
is exposed to 500 ppm CH4 while only 0.16Hz per ppm to the same concentration of CO. Such sensitive properties of gas
sensor in the constant concentration of CH4 at different temperature are also characterized. The result shows that
temperature would affect the sensitive property of gas sensor.
Performance optimization of polymer doped electrophosphorescent organic light emitting diodes
Author(s):
Xiaoqing Tang;
Junsheng Yu;
Wen Wen;
Lu Li;
Yadong Jiang
Show Abstract
Polymer doped electrophosphorescent organic light-emitting diodes with a structure of indium tin oxide (ITO)
/poly(N-vinylcarbazole)(PVK) : bis(1,2-dipheny1-1H-benzoimidazole) iridium (acetylacetonate) [(pbi)2Ir(acac)]
(1wt%)(70 nm)/bathocuproine(BCP)(× nm)/tris(8-hydroxyquinolate)-aluminum (Alq3)(30-× nm)/Mg:Ag have been
fabricated. The light-emitting layer is processed by doping noble metal iridium complex (pbi)2Ir(acac) into a carbazole
copolymer of PVK matrix with the low doping concentration of 1wt% using spin coating method. The influence of film
thickness of the hole blocking layer and electron transporting layer between the emitting layer and the cathode on the
performance of device are investigated. Results show that to keep the whole thickness of the hole blocking layer and
electron transporting layer as a constant, charge carrier recombination zone is transferred from electron transporting layer
to light-emitting layer by gradual increase the hole blocking layer thickness. The device performance is enhanced
simultaneously. The efficiency enhancement may be attributed to the formation of a narrow recombination zone, in
which both charge carriers and excitons are confined. High charge concentrations in the emissive layer results in the
efficient collision capture in the electron-hole recombination process, and exciton confinement leads to improving energy
transfer and charge trapping in polymer doped phosphorescent system.
Photochemical surface modification of flexible plastic substrate for organic light-emitting diodes
Author(s):
Yadong Jiang;
Hui Lin;
Shuangling Lou;
Junsheng Yu
Show Abstract
A method using UV-curable epoxy resin is described to modify organic polymer substrates without changing the bulk
properties of substrate material. The reagents contain an acrylate or other photoactive group which, when exposed to
light of appropriate wavelength, generates highly reactive intermediates that covalently bond with nearly any organic
material. Applying epoxy resin onto the surfaces of such materials, the surface properties can be modified to achieve
greatly increased bond strengths with conventional adhesives. Flexible organic light-emitting diode (FOLED) is
fabricated on indium-tin oxide (ITO) plastic substrate by inserting a UV-curable epoxy resin as a buffer layer between
plastic substrate and ITO film. A maximum luminance of FOLED of 4,860 cd/m2 at 12 V is obtained.
Influence of hole transporter doping on electroluminescent property of novel fluorene molecular material
Author(s):
Jincheng Qian;
Junsheng Yu;
Shuangling Lou;
Yadong Jiang;
Qing Zhang
Show Abstract
The luminescent characteristics of a novel small molecule fluorene material,
6,6'-(9H-fluoren-9,9-diyl)bis(2,3-bis(9,9-dihexyl-9H-fluoren-2-yl)quinoxaline) (BFLBBFLYQ) for organic
light-emitting diode are systemically investigated, especially focusing on the effect of hole transporter doping
concentration. Double-layer devices with a structure of indium tin oxide (ITO)/emissive layer
(EML)/2,9-dimethyl-4,7-diphenyl-l,10-phenanthroline (BCP)/Mg:Ag are fabricated by spin-coating method, where EML
is BFLBBFLYQ and blend of BFLBBFLYQ: N,N'-biphenyl-N,N'-bis-(3-methylphenyl)-1,1'-biphenyl-4,4'-diamine
(TPD), respectively. The results show that the performance of the device is improved two magnitudes by doping
BFLBBFLYQ with TPD. In the electroluminescent (EL) spectra, the BFLBBFLYQ device show a blue light emission
peaking at 485 nm, and the blend device exhibits a broad banded emission with 45 nm red-shifted peaking at 530 nm in
green light area. The photoluminescent (PL) spectra of BFLBBFLYQ, TPD and BFLBBFLYQ: TPD blend in xylene
solution and spin-coated film is also studied, yielding an evidence that exciplex maybe plays the role for low energy
emission.
Studies on PZT membrane resonant gas sensors
Author(s):
Wenjing Zhao;
Xuesheng Li;
Liangfeng Xu;
Jun Yao;
Limei Xu;
Yi Ma
Show Abstract
This paper presents a piezoelectric micro-bridge structure as a resonant gas sensor. The proposed micro-sensor is
designed to expand the narrow range of frequency changing and make correction convenient for detection. The
mechanical performance was simulated to obtain optimum design parameters by finite element method. The relationship
between dimensions, layer thickness and resonance frequency is discussed. The results show that resonance frequency
increased by about 0.6 MHz with a 8.25e-16 kg mass rise in gas-sensing layer in the frequency range of 8 GHz to 8.5
GHz. Thus, the sensor is very sensitive to the change of membrane mass and this makes it very suitable for concentration
sensitive detector. Finally the fabrication process for the sensor suitable for batch fabrication is proposed.
Study and comparison of two novel laser crystals Dy:NaGd(WO4)2, Dy:NaLa(WO4)2
Author(s):
Junjie Yang;
Wenqin Yang;
Ji Wu;
Shangyuan Feng
Show Abstract
Absorption spectra and Raman spectra of Dy:NaGd(WO4)2(Dy:NGW) and Dy:NaLa(WO4)2(Dy:NLW) crystal at room
temperature are investigated. Although the structure of them are similar, there is a bit discrepancy between Dy:NGW and
Dy:NLW of the set of spectra corresponding to the radius of Nd3+, La3+ and Gd3+. According to J-O theory, the oscillator
strength and intensity parameter are calculated and discussed. Due to the disordered structure of the host, the absorption
bands are strongly inhomogeneously broadened. The absorption broad bandwidth reduces the requirements on laser
diodes for zero-phonon-line (ZL) pumping with respect to the spectral bandwidth and wavelength stability for different
power levels. The same differences happen in the Raman spectra. It is beyond doubt that Dy3+-doped compounds,
including the low energy-phonon crystals will be one kind of very promising material in the laser application.
Experimental system of ternary logic optical computer with reconfigurability
Author(s):
Zhang-Yi Shen;
Yi Jin;
Jun-Jie Peng
Show Abstract
An experimental system of a ternary logic optical computer, including its working principle, architecture and main
components, is proposed. The main object of this paper is to give readers a holistic understanding of the ternary optical
computer. This experimental system, which fully exploits the parallelism of optics, can have huge data bus width that is
difficult for the general electronic computer to realize. The completeness of this system not only proves the feasibility of
the ternary optical computer principle and the decrease-radix design theory, but also sets down a solid foundation for the
research of the practicable hundreds-trit ternary optical computer.
Construction of a portable UV-VIS spectrophotometer
Author(s):
Sixiang Zhang;
Duogang Ran;
Feng Wan;
Cheng Li
Show Abstract
In this paper, a method for designing a portable UV-Vis Spectrophotometer is introduced. A miniaturized dispersion
system is developed based on Hamamatsu array detector S3904 - 1024Q and flat field concave holographic grating. In
order to solve the contradiction between spectral width and energy-utilizing ratio of light source, multi-band optical
fibers are employed, which one side of the multi-bands optical fiber is arranged to be rectangle as incidence slit. The
touch screen is employed as input and output system of the spectrophotometer and the miniaturized fiber-optic UV - Vis
light source is employed as light source. The research and testresults of prototypes show that the new spectrophotometer
based on our new method is miniaturization in volume (190*170*100mm3), can realize multi-wavelength detection
on-line, is easily handled (touch screen control) and the performance accords with the Chinese National Standard.
Preparation and optical performance detection of acid-leaching optical fiber image bundle
Author(s):
Dechun Zhou;
Fengxia Yu;
Fang Tan;
Jingjuan Lu
Show Abstract
This article determines three kinds of materials: core and clad glass,cladding glass,acid-leaching glass and the match
ability of physical and chemical performances of these materials is described.. The quantitative relationship between
concentration, temperature, acid type and resolution time are studied to determine a series of suitable technical
parameters. Many effective methods are identified to improve optical properties through a lager number of detecting and
analyzing the properties of fiber image bundle, which lays a good foundation for wider application.
Study on test metrology of large aperture optical system wavefront
Author(s):
Zhiying Liu;
Yuegang Fu;
Tianyuan Gao;
Zhijian Wang
Show Abstract
Large aperture optical system test has been a key problem for a long time. It could be solved by sub-aperture stitching
method after the sub-apertures are tested. Sub-aperture stitching technology is a feasible method for testing large
diameter optical system with small diameter interferometer sub-aperture stitching. Auto-collimating component will be
needed with interferometer stitching method. Auto-collimating component is defined that the image could be kept stable
when the optical component rotates about any axis in space. And the beam could be back along original optical path. By
this means, auto collimation could be realized. The auto-collimating component is smaller than the test system. The
whole wavefront of large aperture system could be tested through the method that the auto-collimating component
moves along the guide rail and rotates about optical axis. A right angle roof prism is chosen as the auto-collimating
component due to its character of easier manufacture. The active matrix, characteristic orientation and extreme axial is
deduced with dynamic optics. The sub-aperture stitching testing process is simulated by ZEMAX in detail. The test
result by stitching method is compared with that by directive test method for large aperture optical system. It is shown
that the relative test error is less than 4.3λ 0/00. The sub -aperture stitching test method is verified.
A neural-fuzzy model with confidence measure for controlled stressed-lap surface shape presentation
Author(s):
Minyou Chen;
Yongjian Wan;
Fan Wu;
Kaigui Xie;
Mingyu Wang;
Bin Fan
Show Abstract
In computer controlled large aspheric mirror polishing process, it is crucially important to build an accurate stressed-lap
surface model for shape control. It is desirable to provide a practical measure of prediction confidence to access the
reliability of the resulting models. To build a reliable prediction model for representing the surface shape of stressed lap
polishing process in large aperture and highly aspheric optical surface, this paper proposed a predictive model with its
own confidence interval estimate based on a fuzzy neural network. The calculation of confidence interval accounts for
the training data distribution and accuracy of the trained model with the given input-output data. Simulation results show
that the proposed confidence interval estimation reflects the data distribution and extrapolation correctly, and works well
in high-dimensional sparse data set of the detected stressed lap surface shape changes. The original data from the
micro-displacement sensor matrix were used to train the neural network model. The experiment results showed that the
proposed model can represent the surface shape of the stressed-lap accurately and facilitate the computer controlled
optical polishing process.
Neural-network-based intelligent control for active stressed lap optical polishing process
Author(s):
Li Yang;
Minyou Chen;
Yonggjian Wan;
Mingyu Wang;
Junhui Zhao;
Bin Fan;
Kaigui Xie
Show Abstract
A neural network based intelligent controller for an optical polishing machine with 60cm diameter active stressed lap has been developed. This paper briefly introduces the shape control strategy of the stressed-lap based optical polishing system. The dynamic change of the surface shape of the stressed lap during the operating process of polishing a large aspheric optical surface is investigated. The principle and structure of neural network based shape control system are discussed. The relationship between the stressed lap driven forces and surface shape is analyzed in detail. The original data from the micro displacement sensor matrix were used to train the neural network model. Simulation results show that the proposed control model can precisely produce the combined driven forces upon given surface shape of the stressed lap and improve the deformation precision.
Theoretical analysis of stressed mirror polishing
Author(s):
Tianxiang Sun;
Li Yang;
Yongqian Wu
Show Abstract
This paper presents the principle of stressed mirror polishing for rapid and low fabrication of the large number of
aspheric mirror. By means of establishing corresponding mathematical model, a proposed method for producing mid or
large sized aspheric mirror is discussed in detail. Based on the mechanics of elasticity, we emphasize the feasibility of
axisymmetric aspheric mirror and prepare for the next investigation of paraboloid mirror.
Electro-rheological finishing for optical surfaces
Author(s):
Haobo Cheng;
Peng Wang
Show Abstract
Many polishing techniques such as fixed-abrasive polishing, abrasive-free polishing and magnetorheological finishing
etc., have been developed. Meanwhile, a new technique is proposed using the mixture of the electro-rheological (Er)
fluid with abrasives as polishing slurry, which is a special process does not require pad. Electrorheological fluid is a
special suspension liquid, whose viscosity has an approximate proportional relation with the electric strength applied.
When the field strength reaches a certain limit, the phase transition occurs and the liquid acquires a solid like character,
and while the electric field is removed, the fluid regains its original viscosity during the order of milliseconds. In this
research work, we employed the characteristics of viscosity change of Er fluid to hold the polishing particles for micromachining.
A point-contact electro-rheological finishing (Erf) tool was designed with a tip diameter 0.5~1mm. Both the
anode and the cathode of the electric field were combined in the tool. The electric field could be controllable. When the
tool moves across the profile of the work piece, by controlling the electric field strength as well as the other
manufacturing parameters we can assure the deterministic material removal. Furthermore, the electro-rheological
finishing process has been planned in detailed.
Athermal design of hybrid refractive/harmonic diffractive optical system for far-infrared multi-band
Author(s):
Ying Liu;
Qiang Sun;
Zhenwu Lu;
Jinying Yue;
Hu Zhang;
Rui Zhu
Show Abstract
In order to get enough information about the target, avoid big chromatic aberration as a result of wide spectrum and the
complexity of optical system and adapt different special environment temperature, a hybrid refractive/ harmonic
diffractive optical system in far-infrared multi-band is described in the paper. This diffractive optical system has been
designed an athermalized multi-band imaging system with harmonic diffractive element in 15-50μm spectrum, based on
larger 1dispersion capability and particular thermal dispersive power of harmonic diffractive element. Then, at the
temperature range from 0°C to 40°C, this design can simultaneously meet with all requirements of the imaging system in
five harmonic wave bands, including15.8-16.2μm, 18.5-20μm, 23-25μm, 30.5-33.5μm and 46-50μm. In each harmonic
wave band, the magnification changes as a function of wavelength, which creates image registration error. To
compensate this shortcoming, a zoom optical system is designed with three lenses by means of optical two- component
method. The design results show that the hybrid refractive/harmonic diffractive optical system can realize athermalized
and achromatic design, and the zoom optical system makes half image height at 3.53mm in every harmonic wave band
and still realizes aberration compensation action. In the five harmonic wave bands, each optical transfer function
approaches the diffraction limit at ambient temperature range of 0°C to 40°C. Finally, the system realizes the
requirements of portability, mini-type and ease for fabrication.
Fabrication of small period blazed reflection gratings by fast atom beam dry etching method
Author(s):
ChaBum Lee;
DoKyun Woo;
JaeYoung Joo;
Sun-Kyu Lee
Show Abstract
This paper presents electromagnetic analysis of Si-based small period blazed reflection gratings for a period of 0.6 -
1.5μm in terms of rigorous coupled wave analysis (RCWA) and its fabrication by using dry etching method. Also,
diffraction characteristics on the facet material are discussed on the basis of its efficiency. First, the optical and
geometrical characteristics of blazed gratings are investigated and the first order diffraction efficiencies for TE and TM
polarization are estimated under the phase-matching requirement for four kinds of gratings (period 0.6-1.5μm). Second,
the optimized blazed gratings are successfully fabricated on a slanted silicon substrate by FAB etching method. From the
results, the first-order TE and TM polarized diffraction efficiencies for four kinds of gratings are evaluated from optical
testing and these results showed good agreement with these theoretical values, respectively. Also, it was found that
diffraction efficiencies of gratings with the smaller period than the wavelength in dimension are obtained 0% for TE and
TM polarization as expected. It is expected that this dry etching method for small size patterning in company with
coating technology can be applicable to high performance optical devices.
Mechatronic system design for tiled large-aperture grating
Author(s):
Lihua Lu;
Yingchun Liang;
Tao Jiang;
Fuli Yu;
Qingchun Zhang
Show Abstract
To obtain a large-aperture high damage threshold grating compressor for a Perawatt laser system, the multi-piece tiled
grating is an effective method. In order to avoid the influence of tiling error on the temporal and spatial characteristics of
grating, the rotation error between sub-gratings needs to be controlled in 1μrad, the piston errors including in-plane shift
and out-of-plane shift errors need to be controlled in 20nm. One mechatronic system is presented for tiled large-aperture
planar gratings based on parallel mechanism with five freedoms. Five uniform feed drives are improved dual mode
mechanism with servomotor and ballscrew as macro-actuator and piezoelectric transducer (PZT) with resolution of
1.2nm as micro-actuator. Key components of the mechanism are optimum designed based on finite element method
(FEM) to achieve proper dynamics of the mechanical system. The proposed system is applied in experiment to tile two
sub-aperture gratings of 200mm×400mm. Far-field diffraction patterns proves that the tiled grating can meet
requirements of accuracy and stability of laser system.
Optimization of removal function parameters in CCOS
Author(s):
Xusheng Zhou;
Yuehua Chen;
Hongbin Shen;
Yongqiang He
Show Abstract
Computer controlled optical surfacing (CCOS) technique is widely used in machining process of large and medium
aspheric surfaces, because of its high accuracy, simple process conditions, low cost and other merits. The characteristic
of the removal function of a polishing tool is a key factor in determining convergence rate in CCOS process. The shape
parameters, which influence the characteristic of the removal function of a dual-rotation polishing tool, are the rotational
speed ratio and the eccentricity ratio. A method is presented to optimize these two shape parameters, in which the error
correcting capability of the removal function is considered. The optimized parameters are compared with those from
other references. The results show that a removal function with a certain size has the highest error correcting capability
when the eccentricity ratio is 0.8 and the rotational speed ratio -3. With the optimized parameters, the final figuring of a
500 mm f3 paraboloid mirror is accomplished. With 95 hours of polishing time, the mirror is taken from an rms
deviation of 0.241 waves to an rms deviation of 0.015 waves, where a wave is 0.6328 μm. The results show that higher
precision and efficiency will be achieved with the optimized parameters in CCOS.
Study on the surface degenerative layer in ultraprecision machining of KDP crystals
Author(s):
Jinghe Wang;
Qingxin Meng;
Mingjun Chen;
Shen Dong;
Zhenxing Li
Show Abstract
The ANSYS analysis method is employed to analyze the stress field distribution within the whole cutting region. The
surface degenerative layer is studied by a nano-mechanical measurement system. The results show that, the forming
mechanism of surface degenerative layer is the change stress distribution in ultra-precision turning. The tensile stress is
major in machined surface. The stress and strain increase with the accretion of depth of cut, and decrease with the
accretion of cutting speed. In the three elements of cutting quantity, the cutting speed has the largest impact on the
thickness of degenerative layer, followed the depth of cut, and the feed rate has the smallest impact.
Dynamic analysis of wiresaw slicing brittle crystals
Author(s):
Tao Sun;
Yanbo Feng
Show Abstract
In the past few years, wire sawing was developed quickly and became the promising brittle crystals slicing technology
because of its advantages of processing large wafers of very small thickness, high surface quality, high yield, and ability
to slice brittle crystals made of various materials. In the process, the thin wire, the processing tools, travels at high speed,
and subjects to external excitation from many aspects. Dynamic effect is directly related to processing result, in this
paper the dynamic effect of wiresaw in cutting region is studied, a suitable model can be present according to continuous
gyroscopic system character. Research on wire oscillation form variation with the change of cutting depth; obtain the
steady state response of wire with different process parameters on wire saw manufacturing process, and a better
understanding of the wire saw operation can be developed. The effect the final surface finish of wafers is analyzed to
improve the process quality.
Frequency-domain analysis on the optical surface accuracy
Author(s):
Qinhua Huang;
Haobo Cheng;
Yongtian Wang;
Peng Wang;
Lingqi Wu
Show Abstract
Residual figure errors on the polished optical surfaces would affect the quality of the optical system. Among them, mid
spatial frequency defects would produce small angle scattering, which has the effects of smearing out of the imaging
core and degrading the resolution. In this paper, taking a classical Schmidt-Cassegrain system into consideration and a
cosine-modulation function is stacked onto the primary mirror surface to simulate and analyze the effect of the mid
spatial frequency. Actually, the mid spatial frequency irregularities could decay the resolution of imaging systems
although the conventional specifications such as RMS and PV meet the requirements.
Error analysis of a rotating mode diamond turning large aspherical mirrors
Author(s):
Cheng-Shun Han;
Long-Jiang Zhang;
Shen Dong;
Jiu-Bin Tan
Show Abstract
A precision rotating mode diamond turnimg method used for machining large optical asphercial elements is introduced.
The position errors between spindles of workpiece and cutting tool system are discussed, and error models of correctly
forming the aspherical reference sphere are set up. The constructed models are used in adjusting the machine for
ensuring the machining accuracy and efficiency.