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- Front Matter: Volume 9283
- Session 4-1
- Poster Session 9283
Front Matter: Volume 9283
Front Matter: Volume 9283
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This PDF file contains the front matter associated with SPIE Proceedings Volume 9283 including the Title Page, Copyright information, Table of Contents, Introduction, and Conference Committee listing.
Session 4-1
Diffractive optical elements: fabrication and application
Show abstract
We review our recent progress on development of the methods for fabrication of precision binary and as well as highefficiency continuous-relief diffractive optical elements (DOEs) by combining complementary advantages of circular laser writing system (CLWS), direct laser beam writing in thermal and photo-sensitive materials and analog lithography. The main limitation and tolerances of writing methods are identified, and their influence on optical performance of DOEs is investigated. The latest results of fabrication and practical applications of DOEs with more than 200 mm diameter and a minimum feature size of 0.5 micrometer for testing large aspheric surfaces with a Fizeau-type interferometer are presented.
Analysis and optimization of a novel laterally deformable optical NEMS grating transducer
Show abstract
This paper discusses the analysis and optimization of a novel optomechanical structure based on a Wood’s type anomaly, in which tiny changes in the spacing of the nanostructured grating elements lead to a dramatic increase or decrease of the optical reflection amplitude. With this special feature, this structure is an ideal sensor component to observe very small amount of relative motion. This device is very sensitive to light source wavelength, the period and the width of the grating. Here, we analyze the performance of the structure with different parameters and incident light of different wavelengths through 3-D Finite Difference Time Domain method (FDTD). Simulation gives out the respective influence of those parameters and the optimized structure designs for different wavelengths which are most possible to fabricate with current surface micromachining processing similar to that used for the fabrication of polysilicon MEMS. The calculated data enables us to apply the structure into fields required for different sensitivities and dynamic ranges with different grating designs and thus broadens the further usage of such novel structure.
Experimental study on elliptical vibration cutting for optical microstructures
Show abstract
In the processing technology of optical microstructure, mechanical processing with high efficiency and quality is still
dominating. However, with microstructure surface quality higher and higher, the precision and ultra precision cutting
technology has been difficult to meet the needs of reality, and it still remains a big issue in production efficiency and
cost. In this case, the elliptical vibration cutting method is created. At present, research on the effect of elliptical
vibration cutting on surface quality of microstructures with special optical properties such as V-groove, micro pyramid
and sinusoidal grid surface is rarely seen. This paper focuses on the elliptical vibration cutting process of arc groove and
V-groove, aiming at finding the discipline of various parameters (frequency, amplitude, feed rate) and analyzing the
surface quality through experiments. Firstly, the principle of elliptical vibration cutting is introduced, the cutting
mechanism and the theoretical error are analyzed, and a vibration cutting system is designed for precision machining.
Because the surface quality and burr play have a huge impact on optical microstructure, effects of the vibration
frequency (0-2kHz), amplitude (0.5-2.5μm) as well as feed rate (6-30mm/min) on surface quality and burr suppression
are analyzed. The experimental results show that compared to normal cutting, elliptical vibration cutting has obvious
advantages. With the increases of the frequency and amplitude, the surface quality improves significantly, the surface
roughness is changed from 61.5nm to 25.3nm, and burr has been suppressed to some extent.
A novel desktop device for lapping thin-walled micro groove
Show abstract
This paper presents a novel desktop device for lapping thin-walled micro groove of a specimen used in optical equipment,
the device is aimed to remove metamorphic layer (about 1μm thick) formed on the groove’s upper surface as well as
ensure its thickness accuracy. It adopts the way of macro/micro motion combination, the macro-motion table uses stepper
motor and ball screws to realize motion in large stroke, high speed and the micron level positioning, the micro-motion
table uses the electrostriction appliance to actuate the flexible four bars mechanism to realize the small stroke, low speed,
and the submicron level positioning. The system uses the strategy of two ways of feedback, the macro/micro motion
table uses the precise linear grating as close-loop position feedback, and the sensing holder uses the eddy current
transducer as the force and deformation feedback of the elastic fixture. The most novel aspect is the first proposed idea of
realizing automatic feeding by elastic recovery of the fixture, whose structure has been delicately designed. In order to
ensure small lapping force and relatively high natural frequency, both static and modal analysis of the fixture has been
done by ANSYS, the results was in good accordance with experiments. Lapping experiments have showed that this
device can remove metamorphic layer efficiently as well as obtain good surface quality at the same time.
Space focusing mirror assembly with flexure hinges
Quanfeng Guo,
Wei Li,
Ji-hong Dong,
et al.
Show abstract
Focusing mirror assembly (FMA) is an important component of large space telescope. It can compensate the telescope's
defocus caused by environmental factors. Telescope launching vibration and shock, as well as the structure stress of
kinematic movement have great impact on focusing mirror assembly. To solve the problems of defocus result from
vibration, shock and other environmental factors, a focusing mirror assembly with flexure hinge structure for space
telescope is developed. Analysis and tests shows that the natural frequency of mirror assembly up to 130Hz. Before and
after the tests, the shape RMS error variation of focusing mirror is less than 0.002λ (λ = 632.8nm). So the flexure support can well meet the requirements of mirror assembly structure performance.
Simulation of internally referenced resonance in a three-layer-coated microsphere resonator
Show abstract
With the finite difference time domain (FDTD) method, whispering gallery modes (WGM) in a microsphere coated with
three layers of high, low, and high refractive index (RI) are simulated. In the simulation, the coupling system includes a
coating microsphere, a waveguide and a nanoscale gap separating the waveguide and the microsphere. A pulse with
ultra-wide bandwidth that spans over several resonant modes of the resonator is used for simulation. Via waveguide
coupling, the relative intensity spectra of the three layers and the transmission spectrum of the coupling system are
obtained. We investigate the effects of the waveguide RI and the thickness of the low-RI layer on resonance
characteristics. It is found that each of the two high-RI layers can sustain its own WGM if the values of RI and thickness
of the three layers are appropriate. Furthermore, the effect of the RI of the surrounding medium on resonance
characteristics is also studied. The simulation results show that a RI change of the surroundings will only change the
resonance wavelength of the outer layer, and will not affect the WGM of the inner layer. Such property makes it feasible
for a potential application in high-precision RI and temperature sensing.
Micromachined fiber optic Fabry-Perot underwater acoustic probe
Show abstract
One of the most important branches in the development trend of the traditional fiber optic physical sensor is the miniaturization of sensor structure. Miniature fiber optic sensor can realize point measurement, and then to develop sensor networks to achieve quasi-distributed or distributed sensing as well as line measurement to area monitoring, which will greatly extend the application area of fiber optic sensors. The development of MEMS technology brings a light path to address the problems brought by the procedure of sensor miniaturization. Sensors manufactured by MEMS technology possess the advantages of small volume, light weight, easy fabricated and low cost. In this paper, a fiber optic extrinsic Fabry-Perot interferometric underwater acoustic probe utilizing micromachined diaphragm collaborated with fiber optic technology and MEMS technology has been designed and implemented to actualize underwater acoustic sensing. Diaphragm with central embossment, where the embossment is used to anti-hydrostatic pressure which would largely deflect the diaphragm that induce interferometric fringe fading, has been made by double-sided etching of silicon on insulator. By bonding the acoustic-sensitive diaphragm as well as a cleaved fiber end in ferrule with an outer sleeve, an extrinsic Fabry-Perot interferometer has been constructed. The sensor has been interrogated by quadrature-point control method and tested in field-stable acoustic standing wave tube. Results have been shown that the recovered signal detected by the sensor coincided well with the corresponding transmitted signal and the sensitivity response was flat in frequency range from 10 Hz to 2kHz with the value about -154.6 dB re. 1/μPa. It has been manifest that the designed sensor could be used as an underwater acoustic probe.
A method for compensating the polarization aberration of projection optics in immersion lithography
Show abstract
As the numerical aperture (NA) of 193nm immersion lithography projection optics (PO) increasing, polarization
aberration (PA) leads to image quality degradation seriously. PA induced by large incident angle of light, film coatings
and intrinsic birefringence of lens materials cannot be ignored. An effective method for PA compensation is to adjust
lens position in PO. However, this method is complicated. Therefore, in this paper, an easy and feasible PA
compensation method is proposed: for ArF lithographic PO with hyper NA (NA=1.2), which is designed by our
laboratory, the PA-induced critical dimension error (CDE) can be effectively reduced by optimizing illumination source
partial coherent factor σout. In addition, the basic idea of our method to suppress pattern placement error (PE) is to adopt anti-reflection (AR) multi-layers MgF2/LaF3/MgF2 and calcium fluoride CaF2 of [111] crystal axes. Our simulation results reveal that the proposed method can effectively and quantificationally compensate large PA in the optics. In particular, our method suppresses the dynamic range of CDE from -12.7nm ~ +4.3nm to -1.1nm ~ +1.2nm, while keeping PE at an acceptable level.
Transmission characteristics analysis of a hybrid SNIMS plasmonic waveguide
Show abstract
We propose a new kind of hybrid plasmonic waveguide structure, namely the semiconductor nanowire -insulator-metal
strip waveguide, or SNIMS. It has been demonstrated using Finite Element Methods (FEM) that this
structure support hybrid plasmonic modes traveling over large distances(100~330um) with strong mode confinement
(ranging from λ2/300 to λ2/30) at telecom wavelengths. The result is better than that of a traditional semiconductor
waveguide. In addition,we stimulated a coupler based on the SNIMS structure. The coupling length Lc can be as short
as 2.2um when the separation D=400nm . In other words, this device can be used as a highly compact directional
coupler.
Vector simulation of pinhole diffraction behavior for high numerical aperture converging incident beam at deep ultraviolet wavelength
Show abstract
For in situ calibration of high numerical aperture wavefront sensor, a small pinhole, whose diameter should be less than
the diffraction limit of incident beam, is used to generate reference spherical wavefront. In this way, the calibration
accuracy is determined by the quality of pinhole diffracted quasi-spherical wavefront. Combining scalar and vector
diffraction theory, a pinhole diffraction model is established to determine the pinhole parameters which could generate
high quality quasi-spherical wavefront. The model includes three steps. Firstly, scalar diffraction theory is utilized to
propagate light from exit pupil of test optics to the pinhole’s incident near-field. Secondly, vector diffraction theory is
used to propagate light from pinhole’s incident near-field to the pinhole’s emergent near-field. Finally, scalar diffraction
theory is utilized again to propagate light from pinhole’s emergent near-field to the detection plane of wavefront sensor.
The most important feature of this model is that the influence of test optics’ exit pupil aberrations on the quality of
reference spherical wavefront can be taken into account quantitively. Based on the modeling approach above, we conduct
a simulation on the pinhole diffraction behavior of light with wavelength of 193.3 nm, X-polarized, numerical aperture of
0.75. The results show that, in order to achieve reference spherical wavefront error of 2 mλ rms, pinhole mask made up
of Chromium membrane with pinhole diameter of 170 nm and membrane thickness of 200 nm should be chosen. At the
same time, the pinhole lateral alignment, pinhole sidewall and pinhole eclipse should be controlled in ±20 nm, ±30 nm and ±10 nm, respectively. Also the requirement on the exit pupil aberrations of test optics is given based on wavefront error and intensity uniformity on detection plane.
Methods on micro lens compact applied in zoom systems
Show abstract
In order to solve the application scope of traditional zoom system, the method of adding new sensors and components,
and update the design method and structure configuration is used. on the basis of geometrical optics and the aberration
theory, the results show that system is optimized by without changing the lens on weight, size and structure. At the same
time the design degrees of freedom is increased, thus breaking restrictions in some kind of zoom systems is been
breaking.
Poster Session 9283
A novel measuring device for step gauge
Show abstract
Combining laser interferometric comparator with high precision inductance sensor, a novel measuring device for step gauge was developed. A high precision laser interferometer system was used for a length standard; a zero-crossing trigger signal of inductance sensor output voltage was used for the aiming signal. In order to improve the measuring accuracy, several high precision sensors were installed to measure environmental parameters for compensating the laser wavelength according to the Edlén empirical equation. A rotating mechanism was designed. Two key problems, probe obstacle avoidance and aiming repeatability, were solved. Experimental analysis of the contact force and speed of influence on measuring probe repeatability, and a segmented control method of the movement speed was established. The experiment indicates that the system has a high accuracy of measurement, which can be used for contact measurement of other one dimension length standard.
3D micropositioning control based on stereo microscopic visual servoing system
Show abstract
In this paper, the global visual servoing micropositioning control method is analyzed and the imaging model is derived based on the CMO type stereo light microscopes (SLM). The model contains no depth information and the left and right image information is used to obtain the image Jacobian matrix. Considering the kinematics characteristics of micro robot, we design an image-based controller. The experimental and simulation results based on the four degree-offreedom (DOF) microrobot system demonstrate the validity of the theory in this paper.
Effect of elastic modulus of PMMA films on its machinability by AFM-based nanoscratching method
Show abstract
In the present study, elastic modulus is used to estimate the machinability of Polymethylmethacrylate (PMMA) films
using an atomic force microscope (AFM). PMMA is widely used in microsystem field as coatings and packaging
materials. A better understanding of its mechanical properties is essential to optimize its application. By spinning coating
PMMA solution on a silicon substrate, the influences of the spin-coating speed and concentration of the PMMA solution
on the thickness of the PMMA films are studied. Results show that the film thickness decreases with the increase of
spin-coating speed and the decrease of solution concentration, respectively. Finally PMMA films with dimensions of the
thickness spanning from dozens to hundreds nanometers are obtained. The atomic force microscope has been
demonstrated to be a useful tool for fabricating and imaging materials at nanometer scale. Elastic moduli of the PMMA
films spin coated with different parameters are evaluated using the PeakForce Quantitative NanoMechanics (QNM)
module of the AFM system. Experimental results show that smaller elastic moduli are measured on thicker PMMA films.
Meanwhile, several V-shape grooves are scratched with the same normal load by AFM probes on different PMMA film
specimens. The relationship between elastic moduli and machinability of the PMMA films is obtained by contrasting the
depth of the grooves.
Multiple spectrum analysis and evaluation for optical constants of HfO2 thin films
Show abstract
HfO2 thin films were deposited on ZS1 silica by Ion Beam Sputtering (IBS) technique. Optical constants of
HfO2 thin films were obtained by multiple spectrum analysis method, which combined the transmittance
spectrum and ellipsometry spectrum of the film. The refractive index and extinction coiefficient of HfO2 thin
films were evaluated by etching experiments of the film. The analysis spectral range was between 250nm and
850nm.
Study on the micro-milling of optical microstructure with the assist of the workpiece vibration
Show abstract
Precision micro-milling technology is an important method to machine microstructure. However, precision micro-milling
cutting system has relatively low stiffness. This will directly lead to the deterioration of the machining quality and thus
cannot fulfill the high accuracy requirements of parts. Vibration assisted machining has produced a good effect in high
stiffness cutting system using non-rotary tool. In this paper, the workpiece vibration assisted method is adopted instead,
to improve the processing condition and the practical machining quality.The vibration assisted system is a vibration
worktable driven by a piezoelectric ceramic actuator. In order to study the influence of vibration frequency on the
machining quality, a non-resonant vibration assisted worktable is designed to realize the adjustment of vibration
frequency. Orthogonal experiment is conducted to study the influence of three factors including the feed rate, vibration
frequency and amplitude on the machining quality. The ranges of these factors are 1 μm/z to 5 μm/z, 500 Hz to 4000 Hz,
and 0.5 μm to 2 μm, respectively. The experimental results show that, in the extent of the process parameters, form error
(P-V value) and roughness (Ra) decrease as the vibration frequency increases, while the vibration amplitude contributes
to good surface quality only in a proper range. Too low amplitude has little influence on the machining quality, and too
high amplitude may even worsen the quality. And after the vibration assisted method is applied, the PV value and Ra can
be reduced by approximately 27% and 42%.
Design and analysis of drum lathe for manufacturing large-scale optical microstructured surface and load characteristics of aerostatic spindle
Show abstract
In this paper, a four-axis ultra-precision lathe for machining large-scale drum mould with microstructured surface is
presented. Firstly, because of the large dimension and weight of drum workpiece, as well as high requirement of
machining accuracy, the design guidelines and component parts of this drum lathe is introduced in detail, including
control system, moving and driving components, position feedback system and so on. Additionally, the weight of drum
workpiece would result in the structural deformation of this lathe, therefore, this paper analyses the effect of structural
deformation on machining accuracy by means of ANSYS. The position change is approximately 16.9nm in the
X-direction(sensitive direction) which could be negligible. Finally, in order to study the impact of bearing parameters on
the load characteristics of aerostatic journal bearing, one of the famous computational fluid dynamics(CFD) software,
FLUENT, is adopted, and a series of simulations are carried out. The result shows that the aerostatic spindle has superior
performance of carrying capacity and stiffness, it is possible for this lathe to bear the weight of drum workpiece up to
1000kg since there are two aerostatic spindles in the headstock and tailstock.
The dynamic analysis of drum roll lathe for machining of rollers
Show abstract
An ultra-precision machine tool for machining of the roller has been designed and assembled, and due to the obvious impact which dynamic characteristic of machine tool has on the quality of microstructures on the roller surface, the dynamic characteristic of the existing machine tool is analyzed in this paper, so is the influence of circumstance that a large scale and slender roller is fixed in the machine on dynamic characteristic of the machine tool. At first, finite element model of the machine tool is built and simplified, and based on that, the paper carries on with the finite element mode analysis and gets the natural frequency and shaking type of four steps of the machine tool. According to the above model analysis results, the weak stiffness systems of machine tool can be further improved and the reasonable bandwidth of control system of the machine tool can be designed. In the end, considering the shock which is caused by Z axis as a result of fast positioning frequently to feeding system and cutting tool, transient analysis is conducted by means of ANSYS analysis in this paper. Based on the results of transient analysis, the vibration regularity of key components of machine tool and its impact on cutting process are explored respectively.
Intelligent control system based on ARM for lithography tool
Show abstract
The control system of traditional lithography tool is based on PC and MCU. The PC handles the complex algorithm, human-computer interaction, and communicates with MCU via serial port; The MCU controls motors and electromagnetic valves, etc. This mode has shortcomings like big volume, high power consumption, and wasting of PC resource. In this paper, an embedded intelligent control system of lithography tool, based on ARM, is provided. The control system used S5PV210 as processor, completing the functions of PC in traditional lithography tool, and provided a good human-computer interaction by using LCD and capacitive touch screen. Using Android4.0.3 as operating system, the equipment provided a cool and easy UI which made the control more user-friendly, and implemented remote control and debug, pushing video information of product by network programming. As a result, it’s convenient for equipment vendor to provide technical support for users. Finally, compared with traditional lithography tool, this design reduced the PC part, making the hardware resources efficiently used and reducing the cost and volume. Introducing embedded OS and the concepts in “The Internet of things” into the design of lithography tool can be a development trend.
Design of a projection objective with high numeric aperture and large view field
Show abstract
As the primary facility for the manufacturing of integrated circuit(IC), and MEMS devices [1], the lithographic
equipment’s improvement is restricted by the projection objective which can decide the capacity of the image
transmission of the facility and make the facility be capable of reaching the higher precision or beyond. On the basis of
the function, increasing the numeric aperture is coupled with the raising of resolution of the projection objective. In this
paper, a design of a projection objective with high numeric aperture and large view field for I-line lithography is
proposed. Owning a dual-telecentric structure this optical system owns an angular magnification of -1.25, an effective
image field of 90×90mm and an image numeric aperture of 0.2. Two aspheric surfaces are adopted in this projection
objective to enhance the quality of imaging that will insure the field curvature lower than a half of the DOF, restrict the
distortion lower than±σ/5 and make the MTF approximate the diffraction limits.
Optical property simulation of liquid crystal on silicon based on finite-difference time-domain method
Show abstract
In the design and development of Liquid Crystal on Silicon (LCoS), one can predict possible problems and propose
according solutions with calculating the director and optical characteristics of the liquid crystal. The optical property of
LCoS is calculated with the Finite-Difference Time-Domain Method (FDTD) in this paper. The diffraction characteristics
are exactly analyzed with incident plane wave and the computational space terminations are provided by a combination
of the perfectly matched layer (PML) and periodic boundary conditions (PBC). The influences on optical properties of
LCoS with different interpixel gap, pretilt angle and thickness are studied. The result shows that diffraction efficiency is
greatly affected by the thickness of cell. It’s significant and offer reference for the design and manufacture of LCoS.
Design of a micro lapping system based on double-feedback control algorithm for manufacturing optical micro components
Show abstract
This paper presents a micro lapping machine tool, which is dedicated for manufacturing the high-precision optical
micro components with 3-D micro structures. And it can remove the damaged surface layer efficiently.In order to control
machining process precisely, a double-feedback control system strategy is proposed and implemented. Lapping force
signal from the clamp feeds back at the same time with position signal from grating scale close-looped devices. With the
function of position keeping , a dual-stage drive micro-displacement servo system is used to provide the desired
performance in the vertical feeding direction. Random lapping trace is formed with combinations of two
mutually-perpendicular horizontal liner motion. A clamp with the function of micro force detection is designed to
monitor the machining process and control the lapping force. Based on force feedback, a tool auto-checking strategy is
conducted to realize the tool checking in limited tiny space. Corresponding experiments are undertaken to test
the properties of the machine tool.And, the optical micro components are manufactured successfully. The optical
components are measured and analysised before and after processing. The experimental results show that the
position-keeping accuracy of the dual-stage feed drive system can reach to ±0.02μm, the resolution of motion control can
reach to 20nm.The Sa value of the processed component can reach 0.0882um. Surface quality can be improved
obviously and the damaged surface layer is removed efficiently.The theoretical and experimental results show the
validity of the machine tool and the control algorithm.
Experimental study on lapping of micro groove with controlled force
Show abstract
Precision parts with complicated microstructures have been in increasing demand in the field of inertial navigation
systems and structured molds. Micro milling is a direct operation to manufacture the micro structure but it will induce
unexpected tool marks and deterioration layer. A novel lapping method based on controlled force is proposed as the final
finishing process. The method offers efficient position determination strategy for the structure and is capable to monitor
the lapping condition. In the paper, processing method and the developed lapping apparatus was firstly introduced. Then,
the individual influence on finished surface of several processing parameters including abrasive size, amount of feed and
lapping trajectory are investigated. Results show that the deterioration layer was successfully removed with different
slurries without diminution of its original form accuracy. Lapping efficiency is also taken into account in the choosing of
parameters. The formative mechanism of parallel scratches observed in experiments is analyzed and verified.
The polarization maintaining and polarization-basis calibrating in the free-space quantum communication system
Show abstract
Free-Space Quantum Communication(FSQC) based on the BB84(Bennett-Brassard 1984) protocol makes use of two groups of conjugate basis polarized photon as the carriers of information to realize the communication between a satelits and a group station. Polarization would show some problems like the contrast of polarization to be worser and the polarization-basis unmatched when transfering. In order to achieve the BB84 protocol, ground station needed to track and calibrate for the polarization zero direction of the satellite equipments. So the polarization maintaining and polarization-basis calibrating is one of the key technologies of the FSQC system. Firstly, this paper established the mathematical model of polarization in the FSQC system, and then derived the mathematical relation between the contrast of polarization and the phase delay in theory. Some proposals of Optical System designs have been suggested in the paper. Finally the problem of dynamic polarization-basis in the satellite-ground link had been analysed and the dynamic characteristic of the deviation angle of polarization-basis in this paper.
ASCOM based research on the universal control protocol of telescope
Show abstract
Remote control for the telescope can greatly reduce personnel requirements for observation and improve the quality of observation. It is important for astronomical observations. ASCOM provide a driver-client layer to separate astronomy device-specifics from the application software that uses those devices in the same time make sure that the drivers are usable from all programming languages. By building the server, client and drivers based on the ASCOM standard protocol to remote control the telescope. The software use Microsoft COM component programming model. Its API consists of a set of standard properties and methods , as defined in the relevant ASCOM interface specification and permit compatibility with all Windows languages. Applications control the operation of the equipment via ASCOM to invoke device driver. Using ASCOM common protocols will greatly improve the scalability and compatibility of system.
Fabrication of resonant subwavelength grating based on thiol-ene
Show abstract
This paper presents an approach used to fabricate resonant subwavelength grating based on thiol-ene material. First of all, polydimethylsiloxane soft imprint stamp with opposite structure of the subwavelength grating master mold is made by casting. Then, the desired subwavelength grating with UV-curable thiol-ene material grating structure is fabricated using the polydimethylsioxane soft stamp by UV-curable soft-lithography. Here, we fabricate a subwavelength grating with period of 300nm using the approach, which could reflect blue light with wavelength ranging from 448nm to 482nm at a specific angle and presents the excellent resonant characteristic. The experimental results are consistent with the simulation results, demonstrating that the approach proposed in this paper could effectively fabricate the thiol-ene material resonant subwavelength grating structure. The thiol-ene material is a new green UV-curable polymer material, including a number of advantages such as rapid UV-curing in the natural environment, low-cost, high resolution, and regulative performance characteristic. The fabrication technique in this paper is simple, low-cost, and easy to high throughput, which has broad application prospects in the preparation of micro and nano structures.
Design and preparation of film for microsphere based optical super-resolution imaging
Show abstract
In this paper, a novel thin film was proposed for optical super-resolution imaging, which contains a layer of closely-arranged barium titanate glass microsphere with diameter about 30-100μm embedded in a transparent polydimethylsiloxane soft mold. Then the imaging mechanism was analyzed by the finite-difference time-domain (FDTD) simulation and spectrum analysis method. Finally, the thin film was prepared and used to image the sample with sub-wavelength feature to confirm the capability of super-resolution imaging. The experimental result shows that an irresolvable Blu-ray DVD disk with feature size of 300nm can be resolved by placing a thin-film on its surface and then look through it with a conventional microscope. The thin film presented here is flexible, lightweight, easy to carry and can be used in the nanophotonics, nanoplasmonics, and biomedical imaging areas.
Visible stealth materials based on photonic crystals
Show abstract
Optical thin film can be used for invisible cloak. As a kind of low-dimension photonic crystal, it is a candidate for metamaterial
with designed Σ and μ. As a coating, it is convenient to be stacked to mimic continuous changing of electromagnetic
media. Anti-reflection film is suitable for matching coating between layers of media.
Design and performance of a wide-angle infrared plasmonic absorber
Show abstract
We study theoretically and experimentally a wide-angle infrared absorber constituting of a periodic array of rectangular metal patches on a thick metal layer, which were spaced by an ultrathin dielectric layer. We use a cavity plasmon resonator (CPR) model to describe the cavity mode field distribution in the absorber analytically and to analyze the resonant conditions and resonant absorption. A plasmonic absorber with square patches is numerically simulated and analyzed based on the CPR model, which shows that the absorption of the absorber is independent of the azimuth angle and remains high at moderate incident angles (θ ≤ 60° ) for both p and s polarizations. The dependence of the resonant wavelength and absorption on the geometric parameters and material of the structure is also investigated, with some design principles proposed for the parameter choice. As a proof-of-principle experiment, we design, fabricate and measure a sample, which shows over 85.7% absorption in the incident angle range of 20°~50° around the wavelength 1160nm for p-polarized incidence, and over 70% absorption around the wavelength 1135 nm for s-polarized incidence.
Nonlinear optical and optical limiting properties of graphene oxide dispersion in femtosecond regime
Show abstract
The third-order nonlinear optical properties of graphene oxide (GO) dispersion in distilled water were investigated in femtosecond regime, using a single beam z-scan technique. Induced by a focused Gaussian beam (λ~800 nm) with 150 fs pulse duration, the graphene oxide shows strong nonlinear absorption, which was dominated by reverse saturable absorption (RSA), originates from two-photon absorption (TPA) in GO. In addition, the optical limiting performance of GO was experimentally derived, indicating that the occurrence of RSA make GO a candidate for optical limiting. In addition, the further increasing of input intensity would enhance the nonlinear scattering effects in the sample so that the optical limiting threshold was reached.
Broadband optical concentration technology based on grating side-coupling
Show abstract
Though the technology of grating side-coupling is often applied in fields, such as coupling of light of single wavelength or
narrow waveband, pump of fiber laser, integration of optical waveguide, its application for broadband coupling of visible
spectrum is rarely studied. Sunlight can concentrate and output at the edge of waveguides by integrating sub-wavelength
gratings with waveguides, making it a novel solar concentrator. In this paper, we simulated different grating structures with
the finite-difference time-domain solution software (FDTD) to obtain the optimal structure design, since different grating
structures feature different diffractive efficiencies. The result demonstrates that the structures mentioned above all feature
good diffractive efficiencies in broadband wavelength, among which the blazing grating reaches the largest efficiency,
namely 48.8%.This kind of sub-wavelength gratings feature integration of small size, which makes it promising in
absorption of solar energy, such as lumination, photovoltaic cell, space melting, etc.
Integral imaging system with a soft substrate
Show abstract
Integral imaging system with soft substrate is proposed and fabricated by lithographic method. The integral imaging
system consists of microlens array and micro-image array. Based on the optical design theory, the geometrical
parameters of the microlens array and micro-image array is calculated and simulated by the software Tracepro.
Furthermore, some experiments are carried out. The microlens array and micro-image array is fabricated on
Polyethylene Terephthalate substrate by lithographic method. After the alignment between the microlens array and the
micro-image array, three dimensional image can be formed over the microlens array. The imaging system is easy to
curve and can be used on some static displays, such as three dimensional display, three dimensional picture and so on.
Uncertainties evaluations in the ray-tracing algorithm based on Monte Carlo method
Show abstract
Although Ray tracing method is an effective aided design method in optical system, the uncertainty caused by this
method is not very clearly. The relationship between the number of rays and uncertainty has been explored in this paper,
while using the Monte Carlo algorithm in Ray tracing method. It shows that if the simulation relative deviation should be
limited to 0.1%, at least 1000000 rays must be used.
A hybrid algorithm for the design of diffractive optical element for beam shaping
Show abstract
A hybrid algorithm based on the simulated annealing algorithm and the iterative algorithm is proposed for the design of diffractive optical element (DOE) to shape the laser beams. The algorithm has the global optimization ability of simulated annealing algorithm as well as the local optimization ability of iterative algorithm. Comparisons between the hybrid algorithm and other two optimization algorithms show that the hybrid algorithm has satisfactory convergence property and design accuracy. Numerical simulation results demonstrate that the diffraction efficiency of the DOE is higher than 94% and non-uniformity is less than 1%. Therefore, this algorithm can be well applied in the field of beam shaping.
Optical trapping force and sensing detection research based on optical fiber shapes and transmission modes
Hongmei Jiang,
Yan Liang,
Pengfei Cao,
et al.
Show abstract
We consider the relationships between the optical trapping force of fiber optical tweezers and the different optical fiber modes and shapes. It is well known that the different optical fiber transmission modes and shapes can bring great influence to the light transmission. We calculate the radiation field of each model in the circle waveguide by using Huygens Fresnel principle. Then, based on the Maxwell Stress Tensor Integral, we can calculate the optical trapping force by using these radiation fields. Through the calculation and simulation, we explain the reason that the optical trapping force of fundamental mode is greater than the high modes in the case of having same shape of exit end face of a waveguide. At the same time, we explore the relationship between the optical trapping force and the fiber taper angles both in the fundamental mode and high modes. And we can obtain the maximum value of optical trapping force by optimizing the fiber taper angle. Optical fiber waveguides have the potential for integration of several functions including the sensing detection. Our results paved the road for utilizing the optical fiber waveguides in nano optical devices, optical trapping, and sensing.
Double drive modes unimorph deformable mirror for femtosecond laser beam wavefront correction
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Once a laser beam suffers from wavefront aberrations, the intensity of the focal spot degrades and the shape of
the focus spot distorts. The same problem also exists in femtosecond laser fabrication system. The aberrations in the
femtosecond laser fabrication system contain two main components: system aberrations and aberrations from the
refractive index mismatch problem. Recently, adaptive optics (AO) has been used for laser beam aberrations correction
to improve the light beam quality. In this paper, we introduce an adaptive optics system with double drive modes
unimorph deformable mirror (DM) into the femtosecond laser fabrication system. In the experiments, the hill-climbing
algorithm based on Zernike modes is used to control the DM to correct the aberrations in the close-loop manner. After
correction for system aberrations and the refractive index mismatch aberrations, the shape and maximum intensity of the
focal laser spot is much improved.
Analysis and correction of drift-induced distortions on quantitative SPM surface roughness evaluations
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The surface roughness at micro/nano scale is essential in the quality of the optical surface. In quantitative
characterization of the roughness surfaces, SPM instruments are widely used due to its ultra-high resolution and powerful
performance. However, drift inevitably exist in SPM measurement and it can distort the quantitative characterization. To
evaluate the SPM measurements of roughness surface more accurately, both the influence discipline of drift on random
surface measurement and the development of effective correction methods need to be studied. Toward this purpose, SPM
imaging of roughness surface with the presence of drift is simulated and influence discipline to roughness surface
parameters was analyzed. Besides, counter-scanning correction method based on identification and matching of feature
points was used to correct the roughness surface. Both simulation and experiment verified the effectiveness of the
employed method. Experimental verification was conducted using roughness reference specimen with specially designed
and processed structural parameters.
Measuring the polarization aberration of hyper-NA lens from the vector aerial image
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Currently, the deteriorated lithography imaging caused by polarization aberration is increasingly prominent. Therefore
measuring the polarization aberration accurately also becomes important. However, traditional polarization aberration
measurement techniques integrated with complex apparatus such as polarimetry and polarizer which result in high cost
for lithography tools. An in situ measurement technique of polarization aberration in hyper numerical aperture (NA)
lithographic tools from the aerial image is proposed in this paper. As the polarization aberration can be decomposed into
scalar phase, apodization, retardation and diattenuation, the first two items are firstly represented by Zernike coefficients
of scalar Zernike polynomials, and the last two items are represented by Zernike coefficients of orientation Zernike
polynomials. Secondly, the linear relationships between the aerial image and the Zernike coefficients of these four items
are established from the rigorous vector imaging theory. Finally, the polarization aberration can be easily obtained by
using above relationships after the aerial images of test marks in different orientations and pitches under different
illumination settings are accurately measured. In addition, the validity of linear relationships and the performance of
proposed technique are clearly demonstrated by numerical simulation for an immersion projector with NA1.35. It is fully
expected that the proposed technique will simple to implement and will be applicable for retrieving the polarization
aberration of projector with hyper-NA.
Research development of thermal aberration in 193nm lithography exposure system
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Lithographic exposure is the key process in the manufacture of the integrated circuit, and the performance of exposure
system decides the level of microelectronic manufacture technology. Nowadays, the 193nm ArF immersion exposure
tool is widely used by the IC manufacturer. With the uniformity of critical dimension (CDU) and overlay become tighter
and the requirement for throughput become higher, the thermal aberration caused by lens material and structure
absorbing the laser energy cannot be neglected. In this paper, we introduce the efforts and methods that researcher on
thermal aberration and its control. Further, these methods were compared to show their own pros and cons. Finally we
investigated the challenges of thermal aberration control for state of the art technologies.