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- Front Matter: Volume 6722
- Session 2-1
- Session 2-2
- Session 2-3
- Session 2-4
- Session 2-5
- Session 2-6
- Poster Session
Front Matter: Volume 6722
Front Matter: Volume 6722
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This PDF file contains the front matter associated with SPIE Proceedings Volume 6722, including the Title Page, Copyright information, Table of Contents, Introduction (if any), and the Conference Committee listing.
Session 2-1
Molding technology of optical plastic refractive-diffractive lenses
Qiming Xin,
Hao Liu,
Pei Lu,
et al.
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Diffractive optical elements (DOE) are becoming increasingly important for realizing compact and low cost optical systems. There are many fabrication methods for realizing the microstructures of DOE with different results.
Injection-molded plastic optics are commonly used to replicate diffractive optical surfaces. Current activities in molding optical plastic hybrid lenses at Chengdu Crystal Technology were presented, including the introduction of hybrid lens used in the lenses for CRT rear projection TV and the making of a kinoform profile on plated-electroless-nickel surface of mold core. Some of defects that degrade the image quality of optical systems, happened in the molding process, were discussed.
Obviously, it is quite important but very difficult by injection molding to get a perfect kinoform profile for high diffractive efficiency and good image quality. Carefully controlling some major parameters of molding process is definitely a key problem, to which every engineer should pay more attention.
Optical design in packaging and illuminating system for high power light-emitting diodes for projection system
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High power Light-Emitting Diodes are used as the illuminating system of the portable projection system more recently. Through analysis the optical structure of high-power LEDs, the LED's optical model and package were simulated and the luminous intensity distribution diagram was obtained. According to the rectangle illuminating requirement of the projection system (the ratio of illuminating length and width is 4:3), a pair of reflective fly eye lens illuminating system with the characteristic of high-bright and uniformity illuminating was designed. Experimental results showed that greater than 85% of the uniform degree of illumination, the output light energy utilization ratio of 80% and the angle of divergence of 38 degree on the object plane were obtained while using the white LED as the light source with illuminating model of Lambertian distribution, luminous flux of 120lm and angle of divergence of 150 degree. This system will be fit for the portable and mini-projection system and other small light-emitting area, uniformity illuminating projection system.
Calculating subtool pressures by using genetic algorithms
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An adaptive lens can be made from plastic and elastic material, its focal distance can be changed by appling radial forces at the lens border ring. To make these kind of lenses it is necessary to figure molds. However, these molds can not be figured by using rigid tools for rapid surfaces. Then we are developing a new technique based in a linear array of independent sub-tools. A linear tool consists of subtools, the pressures of each one can be regulated according to the measured surface errors. The pressures are given by weights put over each sub-tool. By using genetic algorithms the pressure values of each subtool have been calculated in order to obtain the optimal wear. They are shown numerical and experimental results for several axisymmetrical surfaces.
An analytical method for curved optical waveguides
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Analytical method for curved optical waveguides plays an important role in dealing with integrated optical devices based on curved optical waveguides. It helps us not only in understanding physical mechanism of waveguides deeply but also in improving performance of existing integrated devices and designing novel elements. Bend loss of curved optical waveguides is always a problem to be focused on. In order to reduce bend loss of curved optical waveguides, a number of strategies have been used. In this paper, we proposed a new method to analyze curved optical waveguides, which combined the conformal transformation method with ray optical method. An intuitionistic physical image of bend loss in optical waveguides was founded from this point of view, then the reason of bend loss was clearly shown. Accordingly, a new strategy to reduce bend loss in curved optical waveguides was given. Compared with general strategies of modifying the refractive indices whatever in core or cladding, the present strategy is totally deferent. This strategy is beneficial to decrease the radiation of propagation modes in curved optical waveguides by increasing the thickness of curved waveguides. Especially, it is more effective in situations that the radius of curvature of the waveguides and the refractive indices of materials were set beforehand. Software simulation based on BPM was used simultaneously as supplemental verification of this new strategy. Moreover, as an example with this strategy, a special design of ring waveguides structure was given.
Φ300 Hartmann field flattening laser beam expander
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As for laser beam expander with high magnification, wide aperture and fast relative aperture, the off-axis aberrations of Galilean and Keplerian structures are difficult to be corrected. Based on third-order aberration theory, a novel field flattening laser beam expander optical system is presented. An aspheric objective is introduced, and a combined eyepiece of Galilean and Keplerian is put forward. As an example, a laser beam expander with magnification 30, field of view 2mrad, clear aperture of objective 300mm, focal length of objective 800mm, and primary working wavelength 0.6328μm is discussed,. Final test results by laser interferometer show that the PV value of the objective is better than λ/10 on axis and rms λ/90, PV value of optical system is better than λ/8 on axis and rms λ/55.
Diamond turning aspheric projector mirrors
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Nowadays ultra precision machining of single-point diamond turning has played an important role in manufacturing high-precision optical components where surface finish is critical. This paper describes how diamond turning technology was applied to fabricate two tight-tolerance, high accuracy aspheric mirrors for a big-screen high-resolution television projection system. The system consists of two mirrors, a primary and a secondary mirror. Both mirrors have off axis rotational aspheric form. In order to get a good finish, the mirror surface was nickel plated and then diamond turned. Post polish was applied to remove diamond turning grooves and to improve the surface quality. As the off-axis aspheric surface could not be measured by conventional profile meter, a white interferometer was used to measure the off axis aspheric form. The measurement results were compared with that of the design CAD model. The form deviation was less than 3 um. The optical performance of the mirrors was tested in an optical lab. The result was very satisfactory. As the diamond turned prototype mirrors worked so wonderfully with the system, mass production of the mirrors by plastic injection is on the way to bring the new products to the market.
Fabrication of x-ray diffractive optical elements for ICF target diagnosis
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The combination of electron beam lithography (EBL) and x-ray lithography (XRL) has been developed to successfully fabricate x-ray transmittive diffractive optical elements (DOE) such as Fresnel zone plates (FZP) and transmittive gratings (TG). In fabrication processes, the master masks of FZP and TG were patterned with high resolution on free standing membranes by EBL and followed by electroplating. Subsequently, the final gold FZP and TG with vertical cross section were efficiently and economically replicated by XRL and electroplating. By using this combined method, FZP based on silicon nitride (SiNx) free standing membrane was achieved with 150 nm width of outermost ring and 6.7 high aspect ratio, due to a novel sandwich resist structure. A series of TG master masks (2000 g/mm, 3333 g/mm, and 5000 g/mm) were fabricated by EBL. Furthermore, final gold TGs with 2000 g/mm and 3333 g/mm were replicated by XRL. The spectrum of 2000 g/mm TG has shown its perfect performance in x-ray spectroscopy.
Experimental study on KDP crystal polishing
B. L. Wang,
H. Gao
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KDP (KH2PO4) crystal is a high-quality nonlinear optical material used for optical frequency-conversion devices and electron-optical switches in solid-state laser drivers for ICF (Inertial Confined Fusion). KDP crystal is considered difficult to machine because it is extremely soft, hygroscopic, brittle and thermally sensitive. This paper focuses on the polishing study of frequency-tripling crystal planes. The influences of different polishing pad, slurry and machining parameters on roughness, material removal rate and surface topography have been studied. Based on above experiment, the feasibility of KDP crystal polishing was discussed.
Process optimization of DLC films by unbalanced magnetron sputtering for laser-induced damage threshold improvement
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Diamond-like carbon films (DLC) have been widely used in the fields of optics, mechanics and materials science due to the high optical transparency, high mechanical hardness and excellent chemical inertness. On the other hand, the laser-induced damage threshold of DLC films, which are used for infrared antireflection protection coatings, is an important index to evaluate the quality of film. However, the films prepared by various processes have different laser-induced damage threshold. Therefore, it is necessary to investigate the damage properties of DLC films under different deposition conditions.
Unbalanced magnetron sputtering (UBMS), on the other hand, combines the advantages of conventional magnetron sputtering (MS) and ion beam assistant deposition. Applying this technique, it is promising to prepare hydrogen-free carbon films with excellent characteristics by physical vapor deposition method.
In this paper described an UBMS system in details. Hydrogen-free DLC films were prepared by this system under various processes arranged according to the orthogonal experiments method. The laser-induced damage threshold of DLC films were investigated by using a 1064 nm pulsed laser at a pulse width of 12 ns following ISO standard 11254. The results indicated that the damage threshold of the DLC films is about 0.2-0.7 J/cm2. It was found that the target current is the most important factor which affects the threshold of DLC films based on orthogonal experiments, compared with other experiment parameters such as argon gas flow rate, substrate bias and excitation current. A optimization process was obtained in this study at a mass flow of 200 sccm, excitation current of 120 A, bias of about -30 ~ -80 V and target current of 8 A. The higher damage threshold of 0.7 J/cm2 was achieved by depositing DLC film under the optimization process.
Session 2-2
Measurement of spatio-temporal dynamics of patterns in dielectric barrier discharge by using a special optical design
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A special dielectric barrier discharge system with two liquid electrodes and a special optical system are designed to study the spatiotemporal dynamics of nonlinear patterns. A rich variety of patterns including square pattern, hexagon pattern, spiral and square superlattice pattern have been obtained. The spatio-temporal dynamics of square superlattice pattern is investigated. Results show that it is an interleaving of two different transient square sublattices with the emerging sequence of S-L-L-S-L-L in one cycle of the applied voltage. The light signals of the two sublattices indicate that the interval of the emergence of each sublattice is at an order of 0.1 μs.
Design for progressive addition lenses
Quanying Wu,
Lin Qian,
Jingchi Yu,
et al.
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Progressive addition lenses design is focused on utilizing the shape of lens surface, which is not rotationally symmetric, and provides power addition. The lenses should meet power variation progressively without allowing the aberrations to attain detrimental values. The principle and e idea of designing progressive addition lenses are introduced. Several kinds of design methods are illustrated, and their advantages and drawbacks are also represented. Based on one of design methods, which the distance and near power points are determined firstly, then an umbilic line of progressive dioptric power is optimized to satisfy realistic requirements on stability of power and binocular compatibility, the form of the progressive power surface will be gotten, a progressive addition lens design that matches the particular visual needs of the patient is given out. Progressive addition lenses were manufactured with Satisloh VFT-compact machine. The lenses manufactured were measured using the Class Plus lens analyzer to provide sphere and cylinder across the surface of the lens. The results of measurement show that the lenses having a progressive power surface with a near portion and a distance portion, the near portion being of higher power than the distance portion, the form of the progressive power surface of the lens is effective to distribute surface astigmatism. In the current study, it is also shown that the optical characteristics of the different progressive addition lenses designs are significantly different from one another. The lenses designed and manufactured meet the needs. Compared with the lenses designed using Seiko software, the performance is similar with each other.
Research on the AI-AIN granular films prepared by D.C. magnetism filter arc deposition
Haifeng Liang,
Yang Zhou,
Changlong Cai
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Aluminum- Aluminum nitride (Al-AlN) granular films were grown on silicon substrate by using D.C. magnetism filter arc deposition. X-ray diffraction, X-ray photoelectron spectroscopy, optical microscopy, surface profiler were carried out to character films' properties. The crystalline orientation, chemical content, surface morphology were researched. The result shows that the films mainly consist of aluminum and nitrogen elements from XPS spectrum, and aluminum and aluminum nitride interfere peak in XRD spectrum were all observed. Furthermore, no metal macro-droplet can be observed from surface morphology.
3D reconstruction from integral images
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Integral Imaging is a technique that is capable of recording and replaying 3D scene in a form of a planar intensity distribution through micro-lens array. According to this technology, 3D scene information is existed in a great deal of "Element Image" under each micro-lens. A true volume spatial optical model of 3D scene can be perceived through the corresponding micro-lens array replaying. With recent progress in the theory and micro-lens manufacturing, Integral Imaging is becoming a practical and prospective 3D display technology and attracting much attention. For application, the generation of a depth map and 3D scene reconstruction from the planar recorded integral image is essential if real and/or computer generated objects are to be integrated within integral 3D images. It is also essential to enable content-based image coding and content-based interactive manipulation to be carried out within Integral images. This paper presented a method of extracting depth information and reconstructing 3D scene directly from planar recorded integral images through viewpoint image extraction, disparity analysis and depth calculation. Experiment proves that 3D scene information can be reconstructed directly from the planar recorded integral images through mathematical analysis (without using micro-lens sheet replaying). The result of the 3D reconstruction also is the foundation in further analyzing 3D spatial resolution of planar recorded integral images.
Research on key techniques of nanometer scale macro-micro dual-drive precision positioning
Xiaohui Xie,
Ruxu Du
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With the development of science and technology, high precision of positioning platform is needed in many areas, for example, cell fusing in biology and precision surgery in medical area. In such areas, both high efficiency and high precision are needed in some cases, for example, semiconductor processing equipment, super precision lathe etc. In a word, precision positioning platform becomes an important tool in exploring microscope world.
Precision positioning platform is a key element in microscope operation. Macro/micro dual-drive precision positioning is a key technique in high-efficiency high-precision area. By such techniques, large distance and high precision can get. In order to realize nanometer scale macro/micro dual-drive precision positioning there are some key problems. First, system structure of macro/micro combination precision positioning platform is worthy to work on. Another key work is realization method of micrometer scale macroscope motion and nanometer scale microscope motion. The third is mechanics, drive, detection and control techniques in nanometer scale positioning of piezoelectric ceramics drive, in which realization of nanometer scale microscope positioning and micro drive is important by solving hysteresis, creep deformation and non-linearity in piezoelectric ceramics driving. To solve hysteresis problem, instead of traditional Preisach algorithm, a new type hysteresis model with simple computation and identification is needed. The inverse model is also easily to get. So we can present new control method to solve hysteresis and creep deformation problem based on this inverse model. Another way, hysteresis and creep deformation problem exist in traditional voltage-feedback power source for piezoelectric ceramics. To solve this problem, a new type current feedback power source for piezoelectric ceramics is presented. In the end, a macro-micro dual-drive super precision positioning mechanism is presented. Combining macro with micro actuator, a system with large workspace and high resolution of motion is presented. The linear direct-drive motor is used in the macroscope motion and high frequency PZT-driven microscope stage is embedded in the motor and compensates the position error. A high-resolution linear encoder is integrated into the closed-loop feedback, which is used to measure the position of the end-effect in microscope scale.
Ferroelectric properties of multi-layer LiTaO3 thin films with Ta2O5 buffer
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The new sol-gel derived multi-layer LiTaO3 thin films with Ta2O5 buffer layer were prepared on Pt/Ti/SiO2/Si substrate using lithium ethoxide and tantalum ethoxide as starting materials. The sol of Ta2O5 was firstly covered on the substrate by spin coating at 6500rpm for 50s and then a rapid annealing at 650°C for 2min to form an about 20nm thick Ta2O5 buffer layer. Multi-layer LiTaO3 thin films were made over Ta2O5 buffer by repeated spin coating at 4000rpm for 30s and then a rapid annealing process at 700°C for 3min. The spectrum of XRD show the crystalline orientation of thin film type Ta2O5 is different compared to powder type Ta2O5. The SEM micrograph of the cross section shows the prepared sample is uniform, smooth and crack-free on the surface and the thickness of LiTaO3 thin film is 0.341μm. The ferroelectric hysteresis loop and leakage current of the prepared sample have been measured using Al/LiTaO3/Ta2O5/Pt structure electrode by a ferroelectric material analyzer PLC-100. The remanent polarization and coercive field of the prepared sample polarized at 13V were 3.4μC/cm2 and 185kV/cm respectively. The leakage current of the prepared sample was 2.66x10-7A at 71.43kV/cm .Experimental results show the prepared sample of LiTaO3 thin film with Ta2O5 buffer has good ferroelectric properties. Ta2O5 buffer introduction between LiTaO3 thin film and Pt substrate can effectively decrease the leakage current and improve the properties of uncooled LiTaO3 infrared device.
Q-switched Yb-doped rod-type photonic crystal fiber laser
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Rod-type photonic crystal fibers (PCFs) bring enormous advantages in Q-switched fiber laser with high pulse energy, short pulse width and good beam quality for its large mode area and short fiber length. In this paper, an acoustic-optic Q-switched photonic crystal fiber laser was investigated by using a 1m-long Yb-doped large mode area rod-type photonic crystal fiber as gain medium. A maximum pulse energy of 0.78 mJ (21.7 KW peak power) and the shortest pulse width of 20 ns were obtained at low repetition rates. A maximum 1033.6 nm average power of 14.5 W was demonstrated at 65 KHz with a slope efficiency of 56%. Further improvements would be obtained by optimizing the experiment configuration so as to achieve shorter pulse width and higher pulse energy.
Preparation and properties of GaP films on ZnS substrate
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By using Radio Frequency and Plasma Enhanced Chemical Vapor Deposition(RF-PECVD), GaP film is fabricated on ZnS substrate. Under low load condition, the film features Vickers hardness of 750kgf/mm2and film thickness of 10μm. With designed and fabricated DLC/GaP/ZnS film system on ZnS substrate with thickness of 4.2mm, the average transmittance in the bandwidth 8~12μm reached 80.4%. It is indicated by the study of deposition rate of GaP film, optical and mechanical properties and anti-rain erosion and anti-sand erosion that the film growing rate will be faster with the increase of RF power and the deposition rate will be decreased because of the increase of substrate temperature, so it is as the lab atmospheric pressure increase. However , it has more defects in films with the increase of RF power and this results in more absorption, reflection and scattering in the IR transmittance. The higher lab atmospheric pressure and vacuum is, the less impurity in the deposited film will be. GaP film has the ability of protecting ZnS substrate from rain erosion and this ability increases by the thickness of film. And the combination of DLC and GaP has excellent property in anti-sand erosion.
Session 2-3
Forecasting model for the machining accuracy of aspheric surface
Dongju Chen,
Yong Zhang,
Feihu Zhang
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Forecasting the accuracy of a machined surface shape is of a great concern for ultra-precision machining. Quick and accurate selection of the machining parameters and prediction of the measuring accuracy of the machined surface may reduce the time of experiment, shorten the cycle of machining and lower down production costs. This paper studied the parabolic aspheric surface, analyzed the main machining factors that affect the aspheric accuracy and established its back-propagation (BP) Neural Network (NN) model with experimental data taken into account. The model was used to predict the machining accuracy of the aspheric surface which is affected by various factors. Its prediction proves that the method is highly accurate.
Development of TIF based figuring algorithm for deterministic pitch tool polishing
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Pitch is perhaps the oldest material used for optical polishing, leaving superior surface texture, and has been used widely in the optics shop floor. However, for its unpredictable controllability of removal characteristics, the pitch tool polishing has been rarely analysed quantitatively and many optics shops rely heavily on optician's "feel" even today. In order to bring a degree of process controllability to the pitch tool polishing, we added motorized tool motions to the conventional Draper type polishing machine and modelled the tool path in the absolute machine coordinate. We then produced a number of Tool Influence Function (TIF) both from an analytical model and a series of experimental polishing runs using the pitch tool. The theoretical TIFs agreed well with the experimental TIFs to the profile accuracy of 79 % in terms of its shape. The surface figuring algorithm was then developed in-house utilizing both theoretical and experimental TIFs. We are currently undertaking a series of trial figuring experiments to prove the performance of the polishing algorithm, and the early results indicate that the highly deterministic material removal control with the pitch tool can be achieved to a certain level of form error. The machine renovation, TIF theory and experimental confirmation, figuring simulation results are reported together with implications to deterministic polishing.
Fabrication of multilayer laminar grating with high efficiency for extreme ultraviolet
Li-Chao Zhang,
Hui Lin,
Chun-Shui Jin,
et al.
Show abstract
The main goal for investigations on multilayer laminar gratings working at the EUV region is to enhance their efficiency. In this article, we demonstrate a routine to fabricate multilayer laminar gratings with high efficiency. This routine comprises three steps: first, preparing grating substrates with ideal groove profile and low roughness by holographic recording and ion beam etching process; second, optimizing fabricating techniques to obtain multilayer coatings with high reflectivity; third, strictly controlling errors of multilayer grating parameters to ensure the coinciding of the optical performance with the expectation. Results demonstrate that this routine is feasible. The measured peak efficiency of -1 order at 12.8nm was 14.3%. Some related issues about efficiency curves such as wavelength separation and suppression of zero order are discussed.
Time-resolved dynamics of 355-nm laser-irradiated surface damage on fused silica
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The dynamics of 355-nm laser ablation on fused silica were studied by instantaneous scattering pulse
measurement and a time-resolved shadowgraph imaging. The sharp increase of scattered light of pumped
pulse is assumed to be the damage precursor, therefore, the damage start nearly at the peak of the
pumped pulse. The plasmas flash due to ion-electron recombination occurred about 21ns after the
peak of pumped pulses. The propagating shock wave and ejected material to the air were imaged by
shadowgraphic technology. The damage process of fused silica under UV laser ablation was also
discussed.
Methods for integrated simulation of high-precision space opto-mechanical systems
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Each disciplinary has its own modeling and analysis tools to solve its own specific field problems. In order to achieve
integrated simulation of high precision space optical systems and predict optical performance respective to the
mechanical and thermal loads, data must pass through different analysis tools. Simulation tools used in the thermal,
structural and optical design process and the relationship among them were first depicted and the integrated simulation
methods were described in detail. Zernike polynomial fitting methods and interpolating approaches were also
demonstrated. Because of the orthogonality of Zernike polynomials, it was not probably used in some situations such as
noncircular apertures and discrete data, and the coupling of Zernike polynomial coefficients and other methods were also
introduced in the paper. The toolkit OMTIA (Optical, Mechanical and Thermal Integrated Analyzer) based on the
methods was developed, which appears as an indispensable tool for engineering practice.
Process monitoring and analysis of atmospheric pressure plasma polishing method
Jufan Zhang,
Bo Wang,
Shen Dong
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Atmospheric pressure plasma polishing (APPP) method is a novel non-contact machining technology. It utilizes atmospheric pressure plasma to excite reactive radicals which cause chemical reactions with surface atoms to perform atom-scale removal process. Since the machining process is chemical in nature, APPP method avoids surface/subsurface defects. The removal process is a complicated integrated action which is affected by many factors, such as radio frequency power, gas ratio, temperature, and the like. Hence, it is necessary to monitor and analyze the process from different aspects and by various means. Through the analysis of atomic emission spectroscopy, the impacting rules of the radio frequency power and gas ratio were investigated. The temperature distribution on the workpiece surface was initially established by experiments and the results correspond well with the qualitative analysis conclusion from finite element method. Then, by initial technology optimization, the removal rate of 1.46mm3/min and Ra 0.6nm surface roughness were achieved in subsequent machining operations.
Replication fidelity improvement of PMMA microlens array based on weight evaluation and optimization
Bing-yan Jiang,
Long-jiang Shen,
Hua-jiang Peng,
et al.
Show abstract
High replication fidelity is a prerequisite of high quality plastic microlens array in injection molding. But, there's not an economical and practical method to evaluate and improve the replication fidelity until now. Based on part weight evaluation and optimization, this paper presents a new method of replication fidelity improvement. Firstly, a simplified analysis model of PMMA micro columns arrays (5×16) with 200μm diameter was set up. And then, Flow (3D) module of Moldflow MPI6.0 based on Navier-Stokes equations was used to calculate the weight of the micro columns arrays in injection molding. The effects of processing parameters (melt temperature, mold temperature, injection time, packing pressure and packing time) on the part weight were investigated in the simulations. The simulation results showed that the mold temperature and the injection time have important effects on the filling of micro columns; the optimal mold temperature and injection time for better replication fidelity could be determined by the curves of mold temperature vs part weight and injection time vs part weight. At last, the effects of processing parameters on part weight of micro columns array were studied experimentally. The experimental results showed that the increase of melt temperature and mold temperature can make the packing pressure transfer to micro cavity more effectively through runner system, and increase the part weight. From the observation results of the image measuring apparatus, it was discovered that the higher the part weight, the better the filling of the microstructures. In conclusion, part weight can be used to evaluate the replication fidelity of micro-feature structured parts primarily; which is an economical and practical method to improve the replication fidelity of microlens arrays based on weight evaluation and optimization.
Session 2-4
Optical design for digital-micromirror device-based infrared scene projector
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This paper describes the principle of Digital Micromirror Device-based infrared scene projector system and analyzes the illumination system. We review traditional illumination systems in critical and kola ways. In order to get more uniform and a low cost illumination system, we use CODEV to design a fly-eye illumination system and a reflective fly-eye lens system. Simulation results by means of CODEV were shown. We propose that a fly-eye illumination system can achieve high quality infrared illumination system and a reflective fly-eye lens system can provide a low-loss illuminator.
Research on long focal length on-axis TMA system for high-resolution remote sensing
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TMA (Three Mirror Anastigmatic) is popular to the design of space-based optical system. This paper describes the characteristics of the on-axis TMA optical system. An on-axis TMA system with 13m focal length is designed and analyzed. To solve the initial configuration parameters, Cassagrain structure is confirmed firstly, and then the tertiary mirror. Based on initial configuration parameters, automatic optimization is executed in ZEMAX program, and design result with excellent image quality is acquired, which shows the procedure we choosed with good advantage of computer processing. As the distortion of the design reaches 1%, its influences on TDICCD brushing camera are discussed. The source of distortion is analyzed and correcting methods are considered. Zero focal power corrector is chosen to correct the distortion, and the corrected distortion is less than 0.02%. The research on on-axis TMA system in this paper makes a foundation for farther high-resolution remote sensing applications.
Design and fabrication of x-ray Kirkpatrick-Baez microscope for ICF
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A hard x-ray (8 keV, Kα line of Cu) Kirkpatrick-Baez (KB) microscope was designed for the diagnostics of inertial confinement fusion (ICF). Three main parts including optical design, fabrication of multilayers, and alignment method were discussed in this paper. According to the deduced equation of aberration in whole field, an optical system was designed, which gives attention to not only spatial resolution but also the collection efficiency. Tungsten (W) and boron carbide (B4C) were chosen as multilayer materials and the non-periodic multilayer with 40 layers was deposited. The measured reflectivity by XRD is better than 18% in the bandwidth range of about 0.3%. Super accurately alignment is another difficulty in the application of KB microscope. To meet the requirements of pointing and co-focusing, a binocular laser pointer which is flexible enough was designed. Finally, an 8keV x-ray tube was used as source in x-ray imaging experiment and images with magnification of 2× were obtained.
Determination of optical constants of zirconia and silica thin films in UV to visible range
Weihua Jin,
Chunshui Jin,
Hongli Zhu,
et al.
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A curve fitting method for determining the optical constants of some dielectric thin films is described with dispersion theory in the paper. A computer program based on Matlab is developed and optimized. The fitting errors are analyzed with theoretical data, which gives very high accurate results. A program is applied to fitting the measured photometric spectra of ion sputtered zirconia and silica thin films in 200-850nm spectra range. The thickness is verified with the method of grazing x-ray diffraction. With the thickness known, the optical constants of zirconia films near the absorption range are obtained with single-wavelength method. As a result, quite good fitting results are obtained with high accuracy. Finally, an ultraviolet (UV) high-pass optical filter is designed with optical constants extracted by this method. The transmission and reflection spectra of the filter are measured and compared to designed spectra. A good coherence was derived.
Fabrication of flat and supersmooth surfaces with bowl-feed polishing process
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Low-scatter supersmooth optical components are wildly used for critical applications such as high power laser systems, mirrors for ring laser gyros, and low-scatter windows. In this paper, a bowl-feed polishing process with fine abrasives to get flat and extremely smooth surfaces is presented. We consider the machining of super-smooth surfaces as a chain consisted of some key nodes, not merely a polishing process. So after the samples of fused silica have been grinded, fine grinded and lapping previously, each step is controlled strictly, a bowl-feed polishing process is adopted to produce the supersmooth surfaces. During the whole polishing process, in order to achieve consistently reliable and meaningful values of both roughness and flatness, every effort is made to get the proper polishing parameters. Abrasives with different grain size distribution and the temperature are taken into account particularly. Two characters of the samples, roughness and flatness, are concerned about in this study. Process controlling by interferometer implies that surface shape is maintained to better than λ/15 RMS (λ=632.8nm), 100 mm in diameter for an extended periods of time, of the order of days. The surface roughness is tested by an interference microscopy. In best cases, the final test result of surface roughness is better than 0.8nm RMS.
Analysis of the force properties of photonic crystal fiber in the v-groove
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This paper uses a contact mechanics and radial crushing strength to analyze the force properties of photonic crystal fiber which is placed in the V-groove. In this paper, we calculate the stress distribution of the fiber in the V-groove under two ultimate conditions. The first one is supposed that fiber is a solid cylinder which is fabricated by isotropy material. The second one is supposed that fiber is a hollow cylinder. It is calculated that the maximal stress of the fiber is the tension. This stress is near the outer air holes which are parallel to the contact surface. Then we use finite-element (FE)approach to testify the result and calculate the maximal stress the photonic crystal fiber could hold. Finally, we present the stress distribution and the strain of the fiber.
Influence of simulation environment on properties of swing system
Yu-min Zhang,
Yuan-yuan Han,
Yu-feng Zhou,
et al.
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Swing system used in the guiding system is a kind of special equipment composed by a piece of silicon carbide mirror and a support structure made of Al alloy. In order to connect them without harm to their properties, epoxy resin is used and is solidified at room temperature. The influence of connecting process on the optical property of the mirror in swing system is studied by testing the wave-front error before and after connecting process. The results show that the connecting process under room temperature has little effect on wave-front error. The deformations of the mirror under gravity fields and thermal fields are analyzed by finite element method. The calculated results show that the surface figures under all conditions are satisfied with the requirement. The deformation of the mirror under gravity field paralleling to axial direction is the largest. When there is temperature gradient, the effect of axial temperature field on the mirror surface is much greater than that of radial temperature field.
Fabrication of waveguide with ferroelectric-domain structure on electro-optical crystal slice
Guoxin Cui,
Yudong Li,
Jing Chen,
et al.
Show abstract
Waveguide is the basic component of integrated optical device. In this work, we introduced a new method to realize switchable waveguide on electric-optical crystals slice. We wrote ferroelectric-domain-inversed pattern in LiNbO3 crystal slice. When we added external electric field on the slice, electric-optical effect operates and the refractive index difference appears in domain-inversed part and its surroundings. Under appropriate configuration, incident beam could be guided along the domain structure. We produced successfully waveguides with width from 10 to 100 μm. Experimental results show that the capability of the waveguides inside LiNbO3 crystal slice could be adjusted by changing the external electric field on the crystal slice. Compared with other production method of waveguide such as ion diffusion, our method is more flexible and more suitable to produce design-free waveguide devices.
Session 2-5
Research of digital MTF test system based on CCD
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A novel measurement system of digital optical modulation transfer function based on CCD is introduced. This system is mainly made of slight source , collimator, detected system, magnify object lens set, CCD, image collect card ,computer and so on. Different algorithms are proposed for two different sighting vanes of the pinhole and the slit. For pinhole sighting vane, three levels of wavelet transformation algorithm are used to denoise, and by the relation of initial point spread function and line spread function, two-dimensional pinhole image transforms two vertical direction line spread functions. Through the algorithms of Fourier transform, the test can be realized. Slit sighting vane adopts the cubic fitting interpolation algorithm to smooth the curve, and Fourier transform to realize the test. The normalized way is used to process data for the two sighting vane algorithm results. Different model photography lenses are separately measured on the test system. It is showed by the test result that the denoised signals for the pinhole sighting vane are quite smooth through three levels of wavelet transform algorithms, and the point spread function transforms to two vertical-directional line proliferation functions, which makes the Fourier frequency spectrum transform simple; and it has better effect for the slit sighting vane to employ the cubic fitting interpolation algorithm to smooth the curve. MTF test precision is 0.04mm on axis and 0.08mm out of axis.
Study on the effects of depositing parameters on the protection performance of plasma polymerized hexamethyldisiloxane coatings
Show abstract
Aluminium thin film is widely used for high reflectivity reflector. However, it is readily corroded in a variety of environments and in oxygen saturated water. Coatings deposition on it is considered as a way of increasing its corrosion resistance. Among all available deposition techniques, the use of plasma-assisted technologies has grown rapidly. Organosilicon monomers have been successfully used as precursors of Si-based films and among them hexamethyldisiloxane (HMDSO) has gained increasing interest owing to its lower cost and higher deposition rates comparing to similar silicon containing monomers. This work studies the effects of depositing parameters on the structure and composition of the coating and at last on the corrosion protection performance concerning their use as protective coatings on reflective aluminum metallisations. Therefore, we have done a serial of experiments and got corresponding samples with different parameters such as HMDSO glow discharge power and depositing time. In the experiments, the plasma polymerized HMDSO thin films have been obtained in a DC glow discharge from the monomer vapor. And then the corrosion protection performances are analyzed by environment experiments. To analyze the reason of the deposition parameters effect on protection performances, the chemical structure and composition of the films have been analyzed.
Computer-controlled fluid jet polishing
Peiji Guo,
Hui Fang,
Jichi Yu
Show abstract
Fluid jet polishing (FJP) is a new figuring process in optical manufacturing. In this paper, we introduced some recent research results on FJP. Firstly, the distribution of removal function and the mechanism of material removal were studied and it is concluded that the material was removed by the collision and shear actions between abrasive particles and workpiece. Secondly, we bring forward several methods to obtain an ideal removal function with the deepest part at the center, and find that the Gaussian-profile removal function can be obtained by controlling the movement of nozzle. Thirdly, the dependence of surface roughness on the characteristics of workpiece is investigated. Finally, to study the edge effect in FJP, the distributions of removal function are investigated when the polishing tool extends beyond the edge of the workpiece, experimental results imply that, to a certain extent, the edge effect in FJP can be neglected for the small polishing tool.
Design of high-resolution Fourier transform lens
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With the development of optical information processing, high-resolution Fourier transform lens has often been used in holographic data storage system, spatial filtering and observation of particles. This paper studies the optical design method of high-resolution Fourier transform optical lenses system, which could be used in particles observation and holographic data storage system. According to Fourier transform relation between object and its frequency plane and the theory of geometrical optics, the system with working wavelength 532nm and resolution 3μm was designed based on ZEMAX. A multi-configuration method was adopted to optimize the system's lenses. In the optical system, a diaphragm was placed at the system's spectrum plane and the system demanded a low vacuum to cut down the influences of atmosphere and other particles. The result of finite element analysis indicated that the influences of vacuum pumping to optics spacing and mirror surface shape very minor, and the imaging quality not being affected. This system has many advantages, such as simple structure, good image quality and a high resolution of 3μm. So it has a wide application prospect and can be used both in holographic data storage system and particles observation.
Influence on optical and electrical properties of silver layer by adjoining Ta2O5 layers
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Two kinds of structural film stacks, Ta2O5\Ag and Ta2O5\Ag\Ta2O5, were made for investigating the influence on the optical and electrical properties of ultra-thin Ag film by e adjoining Ta2O5 layers. Different samples were prepared by changing the deposition condition of Ta2O5 with different Argon pressure and sputter power. All samples have a uniform 6nm thickness of Ag layer controlled by deposition time. Optical and electrical measurements were carried out on samples and from the transmission and reflectance spectrum the optical constants can be derived. For Ta2O5\Ag film stacks, from measurement we found that the optical and electrical properties of 6nm Ag film strongly depend on the deposition condition of Ta2O5 layers. The sheet resistance is changed from 12Ω to 31Ω and reflectance is changed from 21% to 46% at 2500nm wavelength, which indicate the difference in Ag layer structure. But for the Ta2O5\Ag\Ta2O5 stacks, the changed deposition condition of the upper Ta2O5 layers just bring slightly shift of the optical and electrical property.
Session 2-6
Special techniques in ultra-precision machining
Li Li,
Xu Min,
Dong Chen,
et al.
Show abstract
As the development of ultra-precision machining, the SPDT (single point diamond turning) was applied for the manufacture of a variety of optical components for its high precision , versatility and lower manufacturing cost. Whereas, the improvement of ultra-precision machining is not only related to the most topnotch equipments in the world but also closely linked to the special techniques in the ultra-precision Machining. Therefore, the industrialization and marketization of the ultra-precision machining will not be realized without these special techniques. This paper introduces the principle, trait and application of some important special techniques which can match the SPDT efficaciously, they are FTS, STS, SSS, ACT, VQ, LADT and UADT techniques.
Super-resolved imaging system with oversampling technology
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It has been a significant issue in the imaging filed to provide the highest possible resolution of an electro-optical imaging system(E-O imaging system). CCD arrays are inherently undersampled and spatial frequency above Nyquist frequency is distorted so as to create ambiguity and Moire patterns for targets imaged by E-O system.. As to this drawback, a system-design project is introduced and discussed in the paper. It's well known that many image quality metrics are linked to MTF. However, CCDs don't satisfy MTF condition, namely, the shift-invariant property, so MTF synthesis can't appraise the whole system simply by the MTF product of the few sub-system ones in E-O imaging system. Then it is depicted how to solve this problem in the following. Finally the analyses and comparisons of the imaging performance parameters with and without super-resolved technologies are shown.
Research on the technology of fluorescence separation from exciting light for LIF detection
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Laser-induced fluorescence (LIF) is widely used in biological detection system in characteristic of high sensitivity and selectivity, especially for microarray biochip readout and capillary electrophoresis detection. In these systems, fluorescence separation from background noise is necessary. In this paper, two methods of fluorescence separation were investigated. One adopts a total reflection mirror with a hole at the center; the other uses a dichroic mirror. For dichroic mirror system, fluorescence could transmit through the filter or be reflected by it. Signal to noise ratio depends on dichroic mirror transmitting spectra and reflecting spectra. For center hole mirror system, partial fluorescence loses during propagating through the center hole directly. Detected fluorescence is the part that reflected by the mirror outside the center hole. Size of the hole in the mirror must be changed in different systems. Performance of system with an f-theta lens as scanning lens for laser focus and fluorescence collecting was simulated. Collinear systems with above-mentioned two methods were set up and compared. Simulated results were verified by experiments.
Optical method for evaluating the impact response of 1" HDD arm
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Mechanical response of an actuator arm of a 1-inch hard disk drive (HDD) against a small and steep impact load is accurately measured by means of modifying the Levitation Mass Method (LMM) whose basic concept was proposed by the first author. In the method, a mass that is levitated with an aerostatic linear bearing, and hence encounters negligible friction, is made to collide with a subject actuator arm and the dynamic bending test for the arm is realized. During the collision the Doppler frequency shift of the laser beam reflecting from the mass is accurately measured using an optical interferometer. The velocity, the position, the acceleration and the inertial force of the mass are calculated from the measured time-varying Doppler frequency shift. The importance and the problems concerning the present knowledge on the mechanical response of an actuator arm of a 1-inch hard disk drive (HDD) are also discussed.
Comparative studies of sol-gel SiO2 thin films prepared by spin-coating and dip-coating techniques
Xiliang He,
Jiehua Wu,
Xiangdong Gao,
et al.
Show abstract
Silicon dioxide (SiO2) film is an important material for semiconductor industry as the gate dielectric material, and optical industry as antireflective coatings, and so on. The sol-gel method has been widely used for the deposition of oxide thin films due to several advantages such as simple and low-cost equipment, normal atmospheric conditions, and ease control of the precursor composition doping. In this work, SiO2 thin film was deposited on BK7 glass substrate by spin-coating and dip-coating techniques, respectively. Three precursor concentrations were investigated, i.e., tetraethylorthosilicate (TEOS): ethanol: water= 1:7:7, 1:10:10 and 1:15:15 (molar ratio). X-Ray Diffraction spectrometry (XRD), scanning electron microscopy (SEM), and UV-VIS-NIR scanning spectrophotometry were used to characterize the crystallinity, morphological and optical properties of deposited SiO2 thin films. Results show that all the SiO2 thin films deposited by the spin-coating and dip-coating are amorphous. SEM analysis confirms that the deposited SiO2 thin films have high surface quality and tight adherence with the substrate. The transmittance measurements indicate that dip-coated SiO2 thin film from gel of low precursor concentration represents better transmittance than that from high concentrations at the range of 600-1200nm. SiO2 thin film spin-coated from gel of high precursor concentration has better transmittance than that by dip-coating, but of opposite results for the films deposited from gels of low precursor concentrations.
Poster Session
Adaptive optics image deconvolution based on a modified Richardson-Lucy algorithm
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Adaptive optical (AO) system provides a real-time compensation for atmospheric turbulence. However, the correction is often only partial, and a deconvolution is required for reaching the diffraction limit. The Richardson-Lucy (R-L) Algorithm is the technique most widely used for AO image deconvolution, but Standard R-L Algorithm (SRLA) is often puzzled by speckling phenomenon, wraparound artifact and noise problem. A Modified R-L Algorithm (MRLA) for AO image deconvolution is presented. This novel algorithm applies Magain's correct sampling approach and incorporating noise statistics to Standard R-L Algorithm. The alternant iterative method is applied to estimate PSF and object in the novel algorithm. Comparing experiments for indoor data and AO image are done with SRLA and the MRLA in this paper. Experimental results show that this novel MRLA outperforms the SRLA.
Manufacturing and photoelectrical properties of P-doped a-Si:H thin films deposited by PECVD
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The effect of gas temperature (Tg) on surface morphology, surface roughness, photoelectrical performances of a-Si:H thin films deposited by PECVD at 250°C substrate temperature has been investigated by atomic force microscopy, spectrometric ellipsometry and semiconductor characterization system, respectively. It is found that the surface morphology and density (ρ) as well as the photoelectrical properties such as refractive index (n), dark conductivity (σ), temperature coefficient of resistance (TCR) and activation energy (Ea) remarkably depend on Tg of SiH4 fed in reaction chamber. The higher the Tg, the larger the clusters of a-Si:H thin films deposited. Also, refractive index of a-Si:H thin films increase as Tg rises and the relationship between Tg enhancement of n and the densification of the films is observed. It is indicated that σ varies by two orders of magnitude but TCR decreases by 1.6 %/°C, and Ea gradually decreases linearly from 289.0 to 138.1 meV with Tg varying from room temperature to 160°C. The results of present study suggest that Tg in PECVD chamber plays an important role in the deposition of a-Si:H thin films and directly affects the surface morphology and photoelectrical properties of films. Control of surface morphology, photoelectrical properties of a-Si:H thin films through changing Tg can be usefully applied to the manufacturing of photoelectrical devices.
Application of neural network and spheric harmonics function to system error correction of electro-optical tracker system with X-Y gimbal
Xingfa Liu
Show abstract
Correction of the system error of electro-optical tracker system could improve the measurement accuracy and guidance accuracy. Least square method has lower accuracy than spheric harmonics function method. Neural network could fit precisely complicated curves or curved faces and the system error of electro-optical tracker system with X-Y gimbal is locate on a curve composed of angle values. Analysis and simulation prove that BP neural network method improves the accuracy than spheric harmonics function method for about 8% and could have wider application scope.
Selection of neural network structure for system error correction of electro-optical tracker system with horizontal gimbal
Xing-fa Liu,
Ming Cen
Show abstract
Neural Network system error correction method is more precise than lest square system error correction method and spheric harmonics function system error correction method. The accuracy of neural network system error correction method is mainly related to the frame of Neural Network. Analysis and simulation prove that both BP neural network system error correction method and RBF neural network system error correction method have high correction accuracy; it is better to use RBF Network system error correction method than BP Network system error correction method for little studying stylebook considering training rate and neural network scale.
All-dielectric broadband non-polarizing parallel plate beam splitter operating between 450-650nm
Wenliang Wang,
Shenming Xiong,
Yundong Zhang
Show abstract
Past research on all-dielectric non-polarizing beam splitter is reviewed. With the aid of needle thin film synthesis method and conjugate graduate refining method, three non-polarizing parallel plate beam splitters with different split ratios over a 200nm spectral range centered at 550nm with incidence angle 45° are designed. Selection of material components and initial stack are based on Costich and Thelen's theory. The results of design and analysis show that it maintains a very low polarization ratio in the working range of spectrum and has a reasonable angular field.
High power high brightness laser source for material processing through incoherent beam combination
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With the continuous increase of output power of double cladding fiber lasers, more effort is put into the researches of the technique of fiber laser beam combination, especially for incoherent laser beam combination because it is easier and with better system stability. Once high power output laser beam is achieved, there would be broad applications in industry, especially for manufacturing and material processing. The combination system's coupling efficiency plays an important role in determining the output power. Through theoretical analysis and numerical simulations, it has been proved that lower lateral off-set and higher grating period would be favorable, also an optimum spot radius exists which corresponds to a maximum value of coupling efficiency. Although lower focal length is helpful in improving the coupling efficiency, there is a contradiction that it makes a narrower fiber array width, which would limits the number of fiber lasers that could be utilized. Thus a moderate value of 20cm is chosen. Based on such optimized parameters, the beam quality M2 is around 2, also a method of two parallel gratings is introduced, which ensures the M2 factor to be around 1. Such combined fiber laser would be of great potential applications in manufacturing and material processing.
Analysis of laser-induction hybrid cladding processing conditions
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A new cladding approach based on laser-induction hybrid technique on flat sheets is presented in this paper. Coating is produced by means of 5kw cw CO2 laser equipped with 100kw high frequent inductor, and the experiments set-up, involving a special machining-head, which can provide laser-induction hybrid heat resources simultaneously. The formation of thick NiCrSiB coating on a steel substrate by off-axial powder feeding is studied from an experimental point of view. A substrate melting energy model is developed to describe the energy relationship between laser-induction hybrid cladding and laser cladding alone quantitatively. By comparing the experimental results with the calculational ones, it is shown that the tendency of fusion zone height of theoretical calculation is in agreement with that of tests in laser-induction hybrid cladding. Via analyses and tests, the conclusions can be lead to that the fusion zone height can be increased easily and the good bond of cladding track can be achieved within wide cladding processing window in laser-induction hybrid processing. It shows that the induction heating has an obvious effect on substrate melting and metallurgical bond.
Fabrication of electrospun nanofibers bundles
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Aligned nanofibers, filament bundle composed of large number of nanofibers have potential applications such as bio-material, composite material etc. A series of electrospinning experiments have been conducted to investigate the electrospinning process,in which some parameters such as polymer solution concentration, bias voltage, distance between spinneret and collector, solution flow rate etc have been setup to do the experiment of nanofibers bundles construction. This work firstly reports electrospun nanofiber bundle through non-uniform electrical field, and nanofibers distributed in different density on electrodes from that between them. Thinner nanofibers bundle with a few numbers of nanofiber is collected for 3 seconds; therefore it's also possible that the addressable single nanofiber could be collected to bridge two electrodes.
Design of an aspheric system of optical probe for visibility meter
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Visibility is an important meteorological observation factor. It shows vital position of shopping, environments monitoring and military zones. The design of optical probe for forward scattering visibility meter belongs to normal energy transmitting system. It needs that there are fewer lenses to be used to prevent energy dissipation. Because there is pollution to the monitoring and heating device, the aspheric system is adopted. The basic performance parameters are calculated according to technical data. And the aberration spectrum and tolerance are determined. Based on above parameters, the structure type of objective, which is combined by aspheric and plano surface, is determined. It is showed from the calculation result that all kinds of aberrations of aspheric objective lens could meet the demand of the system.
Study on the optical properties of a one-dimensional periodic multi-layered thin film with gain
Liang Liang,
Zhou Chao
Show abstract
One-dimensional photonic crystals with periodic structure have been limited to only one direction in space and have been around for quite a long time in the very fertile field of thin film optics. Our periodic many-layered thin film (1-D Photonic Crystal) model consists of two types of layered medium in which one layer has gain. The optical properties of transmission and reflection are studied in this 1-D Photonic Crystal with gain. The relationship of transmission coefficient with wavelength, gain and the thickness of media, and the relational expression of critical length with gain are all obtained by using the transfer-matrix method. The mode of divergence points of transmission coefficient depend on the gain, thickness and thickness of monolayer media are analyzed, and it is compared with the Fabry-Perot (F-P) system. It is found that the gain suppress the transmission and the media will be equivalent to a reflector when the gain is large. These simulated calculations are valuable in the design of optical device based on photonic crystal.
Stratified scattering model for inhomogeneous dielectric multilayer coatings
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A stratified model for scattering from multilayer coatings due to roughness of inhomogeneous interfaces is introduced in the paper. It assumes that a rough interface between two media of multilayer coatings consists of a series of very thin, homogeneous sub-layers and that there is an exponential increase in refractive indices of those sub-layers. Matrix method was used to deduce the formulation for calculating the total integrated scattering (TIS). ZrO2 coatings were deposited on BK7 glass by electron beam evaporation, and their scattering properties were measured and calculated by the scatterometer, the stratified scattering model and the existing uncorrelated surface roughness model, respectively. It is shown that the calculated results based on predictions of the stratified scattering model are in closer correspondence with the experimental data than that obtained with uncorrelated surface roughness model.
Influence of cutting parameters on diamond turning titanium alloy
Yuan-liang Zhang,
Zhi-min Zhou,
Wei Xiu,
et al.
Show abstract
Titanium and its alloy have wider application prospects in such engineering fields as aerospace and nuclear energy. Presently, most of the ordinary cutting tools couldn't meet the requirement when machining those materials, even if cubic boron nitride and precision ceramics tools as their limitation of physics performance. But natural single crystal diamond tool can be applied to lens manufacture with high accuracy and surface quality as its sharp enough knife-edge used to extremely shin cutting. However, its easily wearing disadvantage limits its application to Titanium and its alloy machining. Ultrasonic vibration is applied to diamond turning of Titanium and its alloy to decrease diamond tool wear and improve the surface quality of work-piece. Under given experimental conditions, when cutting distance is less than 2000 meters, the work-piece surface roughness(Ra) is lower than 0.25μm and the wear width of rear sides of cutting tools less than 8μm. If increasing the amplitude, surface quality of titanium alloy will be improved a lot. With amplitude increasing, diamond tools wear alleviates obviously. Experiment reveals that the effect of cutting depth on surface roughness is distinct. Roughness increases with the increase of cutting depth.. The effect of feed rate on surface roughness(Ra) is obvious. Surface roughness(Ra) increases with the increase of feed rate.
Analysis for dynamics decoupling of photoelectric tracking system with collimated axis eccentricity
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The horizontal or X-Y tracking gimbal of photoelectric system has spatial blind region because of themselves framework limit, In order to solve the problem of blind region and also track object with high-precision and speediness, a new three-axis photoelectric theodolite system with collimation axis eccentricity is brought forward, It can achieve large-scale space tracking by means of mutual conversion of tracking modes.
There is dynamics and inertia coupling in the three-axis photoelectric tracking system, the kind of coupling will directly affect the static state, dynamic state characteristics and indeed system stability. To get high performance photoelectric tracking system, dynamics coupling must be took into account in three-axis photoelectric tracking system. The matrix transformation of angle velocity and moment can be derived from the reference frame relation of three-axis photoelectric tracking system with collimation axis eccentricity; the kinematics property is analyzed by momentum theorem and angular momentum theorem. Through the analysis of inertia coupling in axes, their object differential equation is gained. In the last, the system nonlinear coupling dynamics model is built using multi-body system theory and Lagrange-Eula equation. From the analysis of dynamic equation, it is evident that the photoelectric tracking system with three input and three output contain complicated nonlinear coupling factor, the study of decoupling control must be carried through in order to get high-precision control system. By importing the geometry coordinate transformation, dynamic compensation and nonlinear state feedback, the nonlinear factor can get accurate elimination on base of the system reversibility of input and output, the three-axis photoelectric tracking system control differential equation can be got nonlinear decoupling by static state feedback, several variable photoelectric tracking system turn into three respective self-governed singularity input and output control system to achieve state or output tracking control.
The coupling and decoupling control system is respectively simulated using MATLAB's simulink toolbox. Simulation results have proved that the decoupling control method proposed and the decoupling controller designed for system are effective.
Novel hole blocking material for organic light-emitting devices
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Two novel boron complexes, i.e, bis (dimesitylboron) stilbene (DMBSB) and bis (dimesitylboronphenyl) acetylene (DMBPA) with the lowest unoccupied molecular orbital (LUMO) of 3.0 eV and the highest occupied molecular orbital (HOMO) of about 6.3 eV.are reported in the paper. Compared to bathocuproine (BCP), the characteristics of two novel materials as hole blocking layer (HBL) were studied in triple layer organic light-emitting devices (OLEDs). The OLEDs were fabricated by conventional thermal vacuum deposition using N, N'-biphenyl-N, N'-bis-(1-naphenyl)-1, 1'-biphenyl -4, 4'-diamine (NPB) as a hole transporting layer (HTL), and tris (8-hydroxyquinolinato) aluminum (Alq) as an electron transport layer (ETL). The results showed that DMBSB efficiently confines the exciton recombination zone into the HTL (NPB layer), and the devices have a current density of 600 mA/cm2 at 19.5 V with a luminance of 504 cd/m2, and a turn-on voltage of 7.7 V. The device of DMBPA material as the HBL has green light emission even with current density of 532 mA/cm2 and a maximum luminance of 1000 cd/m2 at 20 V, and a turn-on voltage of 7.9 V. The electroluminescent (EL) spectrum showed an emission peak at 516 nm with a shoulder at 429 nm, corresponding to CIE coordinates of (0.28, 0.40), which indicates that light emission from Alq layer and NPB layer occurres simultaneously.
Research on special prism processing craft
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Sphere-prism is one of the elements often used in an off axis optical system. Reasonably using a sphere-prism, a series of optical systems with different applications can be designed. These systems have the advantages of small size, less weight and compact structure, and have some optical features which are hardly achieved by a centered optical system, expanding the applications of optical system. In this paper, the technology of making a sphere-prism, a new optical element, is described. At first we make the sphere surface, ans then we make the plane section of a sphere-prism. The professional optical instrument is used to guarantee the angular accuracy in the work of making the plane section. A binocular comparison goniometric angulometer 48°and 90°mater prisms are used to detect the position of spherical center. In the end, a plan that making the spherical section firstly and making the plane section lately is put forward to make sphere-prism. Finally , we give out the fabrication result of the sphere-prism.
Viewing angle analysis of integral imaging
Hong-Xia Wang,
Chun-Hong Wu,
Yang Yang,
et al.
Show abstract
Integral imaging (II) is a technique capable of displaying 3D images with continuous parallax in full natural color. It is becoming the most perspective technique in developing next generation three-dimensional TV (3DTV) and visualization field due to its outstanding advantages. However, most of conventional integral images are restricted by its narrow viewing angle. One reason is that the range in which a reconstructed integral image can be displayed with consistent parallax is limited. The other is that the aperture of system is finite. By far many methods , an integral imaging method to enhance the viewing angle of integral images has been proposed. Nevertheless, except Ren's MVW (Maximum Viewing Width) most of these methods involve complex hardware and modifications of optical system, which usually bring other disadvantages and make operation more difficult. At the same time the cost of these systems should be higher. In order to simplify optical systems, this paper systematically analyzes the viewing angle of traditional integral images instead of modified ones. Simultaneously for the sake of cost the research was based on computer generated integral images (CGII). With the analysis result we can know clearly how the viewing angle can be enhanced and how the image overlap or image flipping can be avoided. The result also promotes the development of optical instruments. Based on theoretical analysis, preliminary calculation was done to demonstrate how the other viewing properties which are closely related with the viewing angle, such as viewing distance, viewing zone, lens pitch, and etc. affect the viewing angle.
Organic light-emitting devices based on different hole transport materials
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The characteristics of N, N'-biphenyl-N, N'-bis-(3-methylphenyl)-1,1'-biphenyl-4,4'-diamine (TPD) and four derivatives, 2,7-bis(p-methoxyphenyl-m'-tolylamino)-9,9-dimethylfluorene (TPF-OMe), 2,7-bis-(phenyl-m'-tolylamino)-9,9- dimethylfluorene (TPF), 2,7-bis(p-fluorophenyl-m'-tolylamino)-9,9-dimethyl fluorene (TPF-F), and 9,9'-(9,9-dimethyl- 9H-fluorene-2,7-diyl)bis(9H-carbazole) (TPG) in double layer organic light-emitting devices (OLEDs) are systemically studied in the paper. The devices were fabricated by conventional thermal vacuum deposition using TPD and its four derivatives as hole transport layer (HTL), and tris(8-hydroxyquinolinato) aluminum (Alq) as an electron transport and emissive layer. Monolayer Alq (50 nm) OLED was also fabricated to compare the HTL role and its effect on device performance. The results show that HTL assisting hole injection and transport improved device luminance performance except TPG material. The monolayer device has a maximum current density of 1270 mA/cm2 at 15 V just due to the thinnest film thickness but a low luminance of 172 cd/m2 at 15 V, and a turn-on voltage (when device luminance is 1 cd/m2) of 6.2 V. The devices of TPD and TPF-OMe as HTL have the maximum luminance of 9813 cd/m2 and 2880 cd/m2 at 15 V, the turn-on voltage of 3.4 V and 4.1 V, and maximum luminance efficiency of 0.52 lm/W at 5.5 V and 0.14 lm/W at 6 V, respectively. The devices of TPF and TPF-F as HTL show the maximum luminance of 2068 and 2515 cd/m2 at 15 V, the turn-on voltage of 4.8 and 4.4 V, and maximum luminance efficiency of 0.12 lm/W at 7.5 V and 0.34 lm/W at 6 V, respectively. TPG material showes incompetent hole transport capability and no redound to device luminescence performance, that device has the maximum current density of 29 mA/cm2 at 15 V , the maximum luminance of 123 cd/m2 at 15 V, turn-on voltage of 10.5 V, and maximum luminance efficiency of 0.10 lm/W at 14 V.
Study on optical polishing of optical glass by means of ultrasonic-magnetorheological compound finishing
Huijun Wang,
Feihu Zhang,
Hang Zhao,
et al.
Show abstract
The paper reports a newly developed optical polishing process by means of ultrasonic-magnetorheological compound finishing (UMC finishing). The machining principle and the experimental procedure of UMC finishing are introduced in the paper for the first time. Experiments are carried out to study the material removal property in UMC finishing of optical glass. The polishing head in UMC finishing is adjusted for different positions to form different angles between its own spindle axis and that of t workpiece during polishing. Experimental results show that the shape of material removal profile changes with the angle. The shape of material removal profile of UMC finishing when the polishing head is oblique is more desirable than the ring-shaped one when the polishing head is vertical. Furthermore, the surface roughness is also analyzed.
Comparison of ion post treatment and laser conditioning of thin films
Show abstract
Laser-induced damage of optical thin films is one of the main obstacles, which prevents laser technology from being developed toward high power. Many experimental results indicated that microdefect and absorption of films are the two major factors that influence laser induced damage threshold (LIDT). To reduce microdefect density and absorption, and improve LIDT of thin films, researchers have developed not only novel film deposition techniques, but also novel film post-treatment techniques. Though film deposition techniques have been highly developed, microdefect still remains to be the main limited factor of LIDT. Because of this, posttreatment techniques as a novel way to reduce defect density and improve LIDT has (been) attracted much attentions. One of the most frequently used posttreatment methods is laser conditioning and another is ion posttreatment. By comparing the treatment mechanism of two posttreatment techniques, it is easy to find their similarities and differences. Though laser conditioning is a classical posttreatment technique, its shortages such as low efficiency, rigorous requirement of equipment stability, and uncertain treatment results are inevitable. As a novel technique, ion posttreatment has great potential to improve LIDT of thin films. This technique not only has high treatment efficiency, but also has convenience and easily adjusted parameters. So it should be a promising posttreatment technique in improving LIDT of optical thin films.
Analyzing the extrusion mould for aluminum profile
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The die or mould used for extruding aluminum wallboard profile is in serious work conditions, so it is easy to appear drawbacks in the mould such as non-uniform stress and strain distributions, crack initiation and propagation, elastic warp, and even plastic distortion. As we know, the extrusion die or mould is subject to complex loads including the extrusion pressure, friction and thermal load, which make the mould complicated and hard to be designed and analyzed by using conventional analytical method. In this paper, we applied Deform-3D, FEA (Finite Element Analysis) software used frequently in all engineering fields, to simulate three-dimensional extruding process of aluminum profile. The simulation results show that the deformation increases gradually from inside to outside. Exterior deformation contour distribution is relative uniform since the influence of inner holes on deformation is small, and the contour form is regular and similar with the shape of the mould. However, the interior deformation contour is irregular as the influence of holes with basically symmetric equivalent curves. At the middle of the mould, the deformation reaches the largest, it reaches 0.633mm. The deformation of the mould can be reduced by increasing the distance between two holes or increasing thickness of the mould. Experiment result accords with simulation. The simulation process and results ensure the feasibility of finite element method, providing the support for mould design and structural optimization.
Inclusion initiated damage studies at repetition rate pulse laser
Fu Dai,
Sheng-ming Xiong,
Yun-dong Zhang
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Theory of laser-induced damage to dielectric films wich contain highly absorbing impurities was proposed previously for single-shot damage of multiple shots. By the model of damage induced by inclusions in dielectric thin-films, with the experiment done by S.Papernov et al who deposited HfO2 thin-films containing gold nanoparticles on a cleaved fused-silica by e-beam evaporation, the absorption cross-section of gold was obtained. Furthermore, the Laser-induced damage threshold induced by inclusions with varies radius and varies repetition frequency was calculated.
Characterization of novel nonlinear optical polymeric film fabricated from dye doped PMMA
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A novel second-order nonlinear optical active dye was doped in poly methyl methacrylate (PMMA) host with a concentration of approximately 10% by weight. The spin-coated film on indium-tin oxide (ITO) coated glass slide was poled at 110°C for 10 min using a corona-discharge setup to orient NLO chromophores. Results from a systematic evaluation to the film physical and optical properties using atomic force microscope (AFM), UV-VIS spectrometer and second harmonic generation (SHG) measurements were presented. The optical absorption spectra of the film show that the absorption peak wavelength is in the vicinity of 505 nm. After electric poling, the UV-VIS spectra exhibit a decrease in absorption. According to AFM images, the surface of the film before poling was flat and clean, however, this good quality film was changed after poling, resulting in numerous hills and valleys on the surface structure, which were aligned to the poling direction. The SHG coefficient (d33) of the poled polymer at 1064 nm fundamental wavelength was determined with Maker-fringe method and obtained as 17.8 pm/V. The relation between the second-order nonlinear coefficients d33 and d31 for the poled polymer film was also discussed in detail in the paper.
Effect of technical parameter on optical constants of amorphous silicon thin film
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In this paper, a series of a-Si:H thin films for about 350 nanometers in thickness were deposited on K9 glass substrate by means of plasma enhanced chemical vapor deposition (PECVD) . During deposition process, there are many factors which influence the optical properties of films. The importance among them includes RF power, substrate temperature and working gas pressure. Technical parameters affect the contents of hydrogen in a-Si:H film. Hydrogen plays a critical role in enhancing the ordering of the film network in a-Si, which can increase nucleation sites and reduce crystallization temperature effectively. The optical constants (n, k) of films were obtained with Forouhi Bloomer (FB) model in spectra ellipsometer (SE) and the absorption coefficient α was deduced from α=4πk/λ.
Effect of annealing temperature on AIN thin films prepared by D.C. magnetism filter arc deposition
Haifeng Liang,
Yan Liu,
Changlong Cai
Show abstract
Aluminum nitride (AlN) thin films have attracted much attention because of its more excellent properties and are widely applied to different fields. In our work, AlN thin films were grown on silicon substrate bying using D.C. magnetism filter arc deposition. Various annealing temperature of 573K, 773K, 973K, 1173K were used to process AlN thin films. Microscopy, ellpsometry and XRD were carried out to character films' properties. The results show that the films' refractive index and the extinction coefficient, processed in different annealing temperature, presented small float and were all less than 5 X 10-3, respectively. Furthermore, from microscopy graph, we can see that the film, annealed in 573-973K temperature, were all un-cracked, uniformity and denser. However, the films show cracking when the annealing temperature reaches 1173K°C. In addition, the XRD spectrum of AlN films show 002 preferred orientation with 973K annealing temperature and show abroad band peaks without annealing.
Fabrication of ZnO thin film Schottky ultraviolet photodetector
Bo Huang,
Guan-nan He,
Yue-bo Wu,
et al.
Show abstract
ZnO films, with C-axis preferred orientation, were deposited on SiO2/n- Si by radio frequency (RF) magnetron sputtering. The interdigital metal-semiconductor-metal (MSM) ultraviolet (UV) photodetectors were fabricated by using Ag as Schottky contact metal. For comparison, ZnO Schottky diodes were also fabricated by using Ag-ZnO-Al structures. Aluminum was used to form Ohmic contacts. Current voltage (I-V) characteristics of these devices have been analyzed. The Schottky diodes exhibit distinct rectifying I-V characteristics. The barrier height of the Ag/ZnO Schottky contacts is around 0.65 eV. The leakage current for MSM photodetector is less than 6 x 10-7A at a bias of 5V. The photoresponsivity of MSM photodetector is much higher in the ultraviolet range than in the visible range. The UV/visible (350nm/500nm) rejection ratio is more than one order of magnitude. The photoresponsivity of MSM detector exhibits a maximum value around 370 nm.
Laser shock wave and its applications
Show abstract
The technology of laser shock wave is used to not only surface modification but also metal forming. It can be divided into three parts: laser shock processing, laser shock forming (LSF) and laser peenforming(LPF). Laser shock processing as a surface treatment to metals can make engineering components have a residual compressive stress so that it obviously improves their fatigue strength and stress corrosion performances, while laser shock forming (LSF) is a novel technique that is used in plastic deformation of sheet metal recently and Laser peen forming (LPF) is another new sheet metal forming process presented in recent years. They all can be carried out by a high-power and repetition pulse Nd:Glass laser device made by Jiangsu University. Laser shock technology has characterized of ultrahigh pressure and high strain rate (106 - 107s-1). Now, for different materials, we are able to form different metals to contours and shapes and simultaneity leave their surfaces in crack-resistant compressive stress state. The results show that the technology of laser shock wave can strengthen surface property and prolong fatigue life and especially can deform metals to shapes that could not be adequately made using conventional methods. With the development of the technology of laser shock wave, the applied fields of laser will become greater and greater.
Optimization of removal function for magnetorheological jet polishing
Xuecheng Zhang,
Yifan Dai,
Shengyi Li,
et al.
Show abstract
The removal function is the fundamental function for the computer controlled optical surfacing (CCOS) process. The removal function of magnetorheological jet polishing is investigated to obtain an optimum one by the method of CCOS. The initial annular footprint is revolved around an eccentric axis resulting in a time-averaged footprint with the largest removal at the center, monotonically decrease to zero at the edge. Similarly if the rotational footprint is traversed in a straight line, the convolved shape of stripe shows a Gaussian-like character. We also calculate the cycloid pattern from parallel scanning by rotational footprint and predict the residual errors on the surface. Calculation results show that the eccentric rotation motion of the jet can lead to improvements in footprint shapes and removal profiles.
Study of optical properties of metallic photonic crystal
Show abstract
We have investigated optical properties of metallic photonic crystals using a standard transfer matrix method. The transfer matrix method for the resonant modes in MPC describes well the splitting of resonant modes and can forecasts the frequencies of split resonant modes in the transmission spectra of the multilayer metallic photonic crystals. Also we have showed that the optical properties of metallic photonic crystals multilayer can be enhanced significantly above the reciprocal metal. Moreover, we showed that the transmittance has a variation as a function of the electronic density of metals.
Design and fabrication of an infrared dichroic filter used for multi-channel image-forming system
Show abstract
Infrared band is so wide that no detector can cover the whole range. In order to obtain relatively wide range of optical signals, multi-channel image-forming system which separates optical signal into several wavebands and images the signal on corresponding detectors is widely used. As an important optical element, dichroic filter is equipped in multi-channel image-forming system frequently to divide optical signal into different wavebands. One kind of infrared dichroic filter was designed and fabricated, the spectrum range covers from 1.6μm to 13 μm and the incidence angle is 45°. The spectral curve was measured by Perkin-Elemer infrared spectrometer. The average reflectance in 1.6 μm~2.2 μm was over 95% and the average transmittance in 9 μm~13 μm was more than 85%. After spectrum measurement and environment reliability experiment, it was found that the infrared dichroic filter was competent to space engineering application.
Theoretical analysis and experimental investigation on V-shape deformation by laser peening
Show abstract
Laser shot peening forming is a novel technique, which employes intense laser to induce residual stress distributed unevenly along the thickness to shape the metal plate. Theoretical analysis and experimental investigation reveal that laser peening forming is a mechanical, not a thermal process. The specimen was peened by laser along the centerline of the specimen, the shape of deformation of specimen is a bulge V-shape, that the plastic deformation centralizes on the narrow laser peening zone, and that other parts of specimen remain at original state but turn around the axis. The stress on both surfaces of deformed plate is compressive residual stress, which indicates that laser peening forming combines plastic deformation with surface improving treatment, and that the workpiece formed by laser peening has longer fatigue life.
Fast speed MWIR imager for uncooled focal plane array
Show abstract
Recent advances of uncooled detector technology especially the development of uncooled micro-bolometer array hold promise for us to develop low-cost and compact MWIR earth observation imager. For comparative lower radiometric performance of uncooled focal plane array, fast speed optical system operating in large spectral bands is compatible. In addition, in order to exhibit advantages over imagers based on cooled detector technology, the optical system should be as compact as possible which means fewer elements, smaller size and light weight. In this article, a high speed optical design meeting these requirement is provided with 100mm focal length, F/1 F number,±2.5°field of view woking in 3-5um wave band. The fast speed MWIR imager has properties mentioned as follows: First, the optical system utilizes a hybrid system including refractive and diffractive elements. Second, the optical system realizes athermalization in simple passive way through distributing power among the refractive elements. It can work under typical temperature scope from -20°C to 60°C for typical space application. Third, Because of high speed aperture, the design makes use of aspheric surface to correct spherical aberration and spherochromatism .Finally, we use Ge and Si material. instead of expensive ZnS material.
Study on CCOS fabrication technology for super-smooth parabolic surface of light-weight SiC mirror
Show abstract
This paper presents a kind of precision fabrication process integrating CCOS polishing with bowl-feed polishing and small tools for grinding is adopted. By analyzing and testing the parameters of each procedure of optical fabricating process of SiC mirror, Φ140mm pressure-burned lightweight SiC parabolic surface is implemented, and the surface figure with high accuracy (PV=0.16λ. RMS=0.026λ, λ=0.6328μm) and super smooth surface (Surface roughness RMS=0.94nm,Ra=0.61nm) are obtained, thus providing a technology support to optical fabrication of hard material aspheric mirror made by CCOS.
Indirect optical thickness monitoring with stationary test-slides for precision optical coatings
Show abstract
In this paper, a novel method, changeable wavelength optical thickness monitoring with quartz crystal thickness monitoring, is firstly outlined for monitoring non-quarter wave thickness. For several multi-layer optical coatings with high performance, a lot of deposition experiments with the ion-assisted deposition technique have firstly done about optical materials SiO2, Ti3O5, and Ta2O5 at room temperature, in order to obtain high dense and low absorbance layers from VIS to NIR wave band. Using the reverse synthesis method, the refractive index, extinction coefficient and tooling factor value of these materials have been obtained accurately. With the above monitoring method, we have then successfully manufactured some multi-layer optical coatings on Bak7 glass and sapphire substrates, and the multi-layer optical coatings have past environmental tests. The appropriate deposition technique parameters and the typical problems about indirect optical thickness monitoring from the deposition process are detailedly discussed in this paper.
Method for characterization and simulation of non-axisymmetric aspheric rough surface
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This paper presents a method for characterization and simulation of the non-axisymmetric aspheric rough surface. With this characterization procedure, simulation of the rough surface is simplified by decomposing the rough surface into two parts, which are the non-axisymmetric aspheric surface and the only rough component without the ideal surface. Then each component of the divided surface is simulated individually. The rough surface exhibits self-affinity and the fractal number D can be associated with any profile and is scale-invariant, and then the rough surface component is simulated with the Weierstrass-Mandelbrot fractal function. An example for simulating a non-axisymmetric and aspheric rough surface is performed and the flexibility of this characterization method is also discussed.
Study on the attitude of dynamic missile based on vertical optical axes binocular vision system
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The binocular vision measurement system is adopted with two CCDs and their optical axes are vertical to obtain the attitude of dynamic missile. Two methods to get the axis vector of the measured missile are discussed in the paper. One is to derive the linear equation of the missile axis' projection line in space coordinate using axle wire method. The other is to obtain the axis vector of measured object based on vertical principle of two CCDs' optical axes. Lastly, with the measured missile attitude measurement principle, the moving attitude from the axis vector obtained above is discussed in the paper too. The result of simulation experiment and analysis shows that the measurement method has higher precision, and can meet the measurement requirement for the dynamic parameter of moving object in long distance.
Effects on residual stresses of Ti6Al4V alloy EBW by laser quenching
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The surfaces of Ti6Al4V alloy EBW (Electron beam welding) were processed by CO2 laser quenching, and residual stresses of EBW were measured with X-ray stress tester X-350A. The mechanism of residual stress was analyzed, the effects of assistant gas and laser power and spot diameter on residual stresses in EBW of Ti6Al4V alloy is investigated. Experimental results show that residual stresses in EBW are increased obviously by CO2 laser quenching under the given laser parameters, which improve its mechanical performances.
Design of broadband dielectric coatings for near-infrared Fabry-Perot interferometer
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Fabry-Perot interferometer has an important effect on near-infrared high spectral resolution spectrograph. In 1896, Ch. Fabry and Alfred Perot designed and used the Fabry-Perot interferometer for the first time. Since then the instruments using Fabry-Perot interference phenomena have been applied broadly to multi-field, such as astronomy, laser, and fiber-optic transmission. Fabry-Perot interferometer has many advantages such as narrow passband, high spectral resolution, high throughput, easy wave-length adjustment, simple structure and large aperture. Comparing with traditional visible light, the solar observation in near-infrared has many advantages: for example, weaker magnetic field strength can be more precisely measured with near-infrared spectrum .So developing the key technology of near-infrared high spectral resolution spectrograph--Fabry-Perot interferometer has become urgent.
For developing near-infrared Fabry-Perot interferometer, there are four difficulties: producing high quality optical plane: peak-to-valley surface flatness better than λ/100; coating Fabry-Perot interferometer plates with broadband multilayer dielectric films(including spectrum performance, thickness uniformity and stress effects); controlling the distance of interference cavity; keeping constant temperature.
In this paper, the process of designing broadband dielectric reflective and antireflective coatings applied in near-infrared Fabry-Perot is described and some problems of designing Fabry-Perot interferometer are discussed: the design of broadband dielectric mirror is described with reflectivity of 93.9±1.0% over spectral ranges from 1.0μm to 1.7μm; by reflective phase shifts in the design of mirror coating, computing the required film thickness uniformity atλ/100 of peak-to-valley surface flatness; degradation of surface figure is perhaps more thanλ/100 even if the soft coating materials-zinc sulfide and cryolite are used, and in order to reduce the degradation of surface figure brought by the stress of dielectric mirror coating, antireflective coating adopts same materials of dielectric mirror coating, ZnS and Na3AlF6, and similar film total thickness.
Influence of various doping ratio on optical and electronic performance of blue organic light-emitting diodes
Show abstract
A novel kind of multilayer blue organic light-emitting diode (OLED) was developed via vacuum thermal deposition method. Host and dopant materials were co-deposited to fabricate as an emissive layer (EML) simultaneously. The film thickness of each layer was controlled with a quartz crystal microbalance. Typical device structure was ITO/CuPc (20 nm)/NPB (60 nm)/B-host (40 nm) : dopant (X wt%)/Alq3 (20 nm)/LiF (1 nm)/Al (100 nm), where X% stands for the doping concentration in the EML of OLED. The weight ratio was changed from 1% to 4%. Optical and electronic performance including current, bias voltage, brightness, efficiency and spectra of the devices varied with doping concentration was characterized. The results showed the turn-on voltage of the device with 1% doping concentration was lower than that of others, which was only 3.5 V. When X wt% was 3%, the brightness of the device reached to be 9,500 cdm-2 at a driving voltage of 20 V with blue emission spectrum peak 472 nm corresponding to the CIE coordinates of x=0.147, y=0.215 and a maximum luminance efficiency of 2.92 lmW-1. The brightness of the device increased linearly with the bias voltage ranging from 3.5 to 52 V. The results also showed that the doping OLED was very steady under high driving voltage at ambient atmosphere.
Distributed optically integrated manufacture system based on CORBA
Ming Cen,
Jian-chun Jiang,
Xing-fa Liu,
et al.
Show abstract
Focused on the shortcoming and insufficiency of reconfigurable manufacture system (RMS) for optical manufacturing in
control layer and interface of manufacturing execution systems (MES) and control layer, the difference of MES-plan
layer interface and that of MES-control layer is discussed, and an architecture of distributed optically integrated
manufacture executing system based on fieldbus/Ethernet network and common object request broker architecture
(CORBA) is presented. In this solution, the optical manufacture equipments are connected by fieldbus network, a
gateway is used for the communication of fieldbus manufacture equipment and MES in the workshop, and CORBA
services which provide a general interface for communication of heterogeneous fieldbus manufacture equipment of
workshop are realized on the gateway. Then all specifics of heterogeneous fieldbus manufacture equipments are
concealed, which show as virtual equipment and can be accessed in a simple and unified way. So the control layer is
composed of virtual equipment and easy to be reconfigured. Similarly workshop management function components are
modeled and encapsulated by CORBA interface, and MES could be integrated to RMS expediently. The optical
integrated manufacture system presented is proved with good ability of flexible, reconfigurable, opening and high
feasibility, and met the reconfigurable requirement of distributed optical manufacturing workshop preferably.
New design of optical focusing system from an axicon combination for laser micro-processing machine
Show abstract
The focusing system is very important for laser processing, especially for laser micro-processing, whose characteristics influence directly the quality of laser processing. A new optical system from the potive axicon and spherical lens combination is proposed in this paper to generate the diffraction-free beam. Only one axicon is needed in this system to produce the variable diffraction-free beam spot of micro order by changing the ordinary cheap spherical lenses. If such an optical system is used as the focusing system for laser micro-processing, the sensitivity to the workpieces' position would be zero and the adaptability to the flatness of the workpieces' surface could be enhanced. Moreover, such a system could adapt well to the different processing criterion by changing the ordinary spherical lenses and would also have potential application in the measurement field.
Designing the actuator distribution of DM based on SPGD optimization
Show abstract
In this paper, we have attempted the stochastic parallel gradient descent (SPGD) algorithm to optimize actuator distribution of deformable mirrors (DM) in an adaptive optics (AO) system. In this process, we use the gauss model as the influence function of DM, and the least square-fitting algorithm is performed to fit aberration wavefront. The center locations of all actuators will be optimized as the controlled parameters, and the RMS of residual wavefront is used directly as cost function for gradient estimation. Numerical simulations for the 32 actuators DM are presented. We get the relative steady optimized distribution of the actuators on the DM for every Zernike wavefront, which can decrease the errors of residual wavefront effectively compared to square pattern. The results show that the optimized distribution of actuators has obvious symmetrical relativity with variety of corrected objects; and it is advisable to place some of the actuators at the outer edge of the effective aperture. The SPGD algorithm has been proved valid for DM design, while the corrected wavefront has some regularity.
Novel automatic angular tracking method for fiber-optic alignment in butterfly laser module packaging
Hao Shen,
Xin Wang
Show abstract
Butterfly packaging technology with a fiber pigtail is widely used in packaging optical modules. Fiber-optic alignment method is used to assure the receiving fiber rapidly capture the maximum optical power from the laser diode. Typically, there are six degrees of freedom that should be aligned synchronously: three linear axes (X, Y, Z) and three angular axes (pitch, yaw and roll). Currently, most fiber alignment algorithms are only suitable for linear axes, and for angular alignment, manual coupling is still widely used in product line. In recent years, engineers have tried to apply some automatic algorithms such as Hill-climbing algorithm to realize angular alignment, but since the pivot point is not always the end point of the fiber tip, an angular movement will cause an extra offset in linear axis. Consequently, the whole alignment process will cost much more time. In this paper, a novel automatic angular tracking method based on machine vision is presented. Two charge-coupled device (CCD) cameras are posited to capture the image of the fiber tip from two different directions. Particularly, digital image processing is used to calculate every extra offset in linear direction and correct the fiber tip back to its original position while angular alignment is beginning. Experiment results show that when using other algorithms to correct the extra linear offset, the total alignment time was more than 200 seconds while the automatic tracking method can reduce the total time less than 160 seconds. It is obviously that this automatic tracking method is rapidly improved the efficiency in butterfly packaging.
Micro-feed mechanism with high-resolution and large-stroke based on friction drive
Haitao Liu,
Zesheng Lu
Show abstract
Based on friction driving principle, design a long stroke length and high resolution walking micro-feeding device driven by piezoelectric ceramic elements and combined with the screw shaft and aerostatic guide way. The design was made to the adjustable preload device by flexible four-bar linkage. The static properties of flexible linkage device are analyzed with FEM. The transmission characteristics of micro-feeding device are exhaustively analyzed.
Rotating sensing based on slow light coupled resonator structure with EIT-like property
Show abstract
We discuss the relationship between Sagnac effect and "slow light" phenomenon, and point out that although the medium and waveguide dispersion can in no way affect the magnitude of Sagnac effect, the highly dispersive structure is still beneficial to the enhancement of Sagnac effect and can be utilized to detect absolute rotation for navigation purpose.
Based on the EIT-like property of coupled resonator structure, a miniature highly sensitive gyroscope is possible. This EIT-like phenomenon occurs through a classical mean in a coupled resonator structure due to all-optical classical interference, called coupled resonator induced transparency (CRIT). With the analogy between optical and atomic parameters, we treat Sagnac effect as a phase perturbation to resonators' optical parameters, and then analyze Sagnac effect in a CRIT structure with a transfer function approach and derive the explicit expression of relative Sagnac phase shift. We find that Sagnac effect is enhanced as a factor as light slows, and can be tailored by adjusting the optical parameters of structure.
Furthermore, as a potential highly sensitive, compact size rotation sensor, some issues for the implementation of CRIT structure based gyroscope are discussed and considered, such as the fabrication possibility, line-width, shot noise limit sensitivity and integration issues. With the improvement of micro-fabrication technique, this gyroscope should have all-solid configuration, compact size and also be expected to achieve comparable sensitivity to common optic-fiber gyroscope. It would be easily integrated to all-optical application and construct a high performance rotation sensor.
Design and fabrication of a non-polarizing broadband dichroic filter
Show abstract
A non-polarizing broadband dichroic filter with high reflectance from 400 to 600nm and high transmittance from 650 to 1000nm was designed with a simple structure and fabricated by electron-beam evaporation with ion-beam-assisted deposition (IBAD). Experimental spectral performances showed a good agreement with the theoretical curves. In addition, the designed dichroic filter can also show high transmission from 670 to 930nm with non-polarization over a wide range of incident angles.
Influence of laser beam on transport dynamics of Si nanoparticles by laser ablation
Show abstract
To investigate nucleation area and transport dynamics of Si nanoparticles, nanocrystalline silicon films were prepared by pulsed laser ablation. Subsequently, the additional laser beam as energy source was introduced, which crossed vertically the plasma plume from the top down in front of the target at a distance of 0.5 cm under same experiment condition. In this region, due to collision between the photon and the plasma plume, the transport of Si nanoparticles was impacted by the cross-laser beam. The Raman and x-ray diffraction spectra (XRD), scanning electron microscopy (SEM) images of the films showed that Si nanoparticles were formed in a certain range, and the average size of Si nanoparticles monotonically decreases with the increase of distance. Obviously, the range of Si nanoparticles deposited in substrates became narrower due to the influence of additional laser beam. Experimental results were analyzed in terms of the nucleation area model.
Optimization of deposition uniformity in a planet rotation system with precise mask design
Show abstract
Generally, substrates in a planetary rotation system result in coatings with nonuniformity of 2% or greater over apertures of 500mm. However, more accurate, uniform deposition of large-aperture optical coatings is required now. So it is very important to study how to improve the deposition uniformity of large-aperture optical coatings. In this paper, we show that a theoretical model that can forecast the thickness distributions of films, get precise figure of masks, and should optimize the deposition uniformity accurately and fast through fixing the designed masks in the chamber.
Automatic alignment between two optical fiber collimators
Jian Xu,
Xin Wang,
Hao Shen
Show abstract
Optical fiber collimators are widely used in many parts of optical apparatus such as optical isolators, optical switch, etc, and the automatic alignment between two optical fiber collimators becomes an important part of the manufacture. Since the automatic alignment process is the multi-degree-of-freedom motion control, the traditional hill-climbing algorithm takes much time and always fails. Based on the optical field formed by the collimator's end, a fast multiple freedom search algorithm is proposed for automatic alignment between two optical fiber collimators. The blind search method is used in coarse alignment process. In this method, the collimator will move in a symmetrical square spiral trace to catch the first light. In fine alignment, the collimator will move in a circle trace to find such two points in which the optical powers are equal, and then the algorithm will forecast the direction of the power increasing. This search method in fine alignment process can adjust misalignments on multiple axial directions simultaneously. Due to this advantage, this fine alignment process is shortened time with little effects of noises and inter-coupling among axes on alignment automation. Experimental results show that the alignment speed of the proposed search method is better than that of traditional hill-climbing algorithm. The cycle time for six-degree freedom, x, y, z and θx, θy, θz, alignment automation is about 120-140s.
Effects of substrate temperature and annealing in air on optical properties of Ag films prepared by thermal evaporation
Jing Lv,
Fachun Lai,
Zhigao Huang,
et al.
Show abstract
The effects of the substrate temperature and annealing in air on the structural and optical properties of Ag films have been studied. Ag films were prepared by thermal evaporation on glass substrates at different substrate temperatures (room temperature, 60 °C and 90 °C). Post-deposition annealing of the film was carried out at temperatures among 250 and 350 °C. Surface morphology of Ag film was observed by atomic force microscopy. Surface composition was detected by Raman spectra. Reflectance was measured by a double beam spectrophotometer. The results show that surface of the annealed films grown at higher substrate temperature is more oxidized. For the annealed film grown at 90 °C substrate temperature, the agglomeration seems to follow the grain boundary grooving process and size of islands increases with increasing annealing temperature. However, the annealed film grown at 60 °C substrate temperature agglomerates via nucleation of voids followed by the fractal growth of voids. It is found that the substrate temperature of the films will affect the agglomeration characteristic of the films annealed at different temperature in air, which results in the difference in the optical properties of the annealed films.
Effects of substrate temperature and annealing on the structure and optical properties of ZnS film
Xiaochun Wu,
Fachun Lai,
Yongzhong Lin,
et al.
Show abstract
Effects of substrate and annealing temperature on the microstructure, morphology, and optical properties of ZnS films were investigated. ZnS films were deposited on glass substrates by an electron beam evaporation system at different substrate temperatures and annealed at different temperatures in air. The structure and morphology of the film were studied by X-ray diffraction and atomic force microscopy. Transmittances of film were measured by spectrophotometer. Refractive indices and extinction coefficients were calculated from all transmittance data. Experimental results show that the as-deposited ZnS film exhibiting cubic structure, and the crystallinity is apparently improved with the increase of substrate temperature or annealing temperature. It is also found that film surface changes to ZnO after the film is annealed at 500 °C. The average surface grain size and root mean square surface roughness increase with the increase of annealing and substrate temperatures. Additionally, the increase of substrate temperature or annealing temperature will increase the pores in films, which results in the decrease of refractive indices and increase of extinction coefficients of the film.
Analysis of ring resonator of integrated optical waveguide gyroscope
Show abstract
Ring resonator is a key unit of integrated optical waveguide gyroscope. Generally the Finite Difference Time Domain (FDTD) method is used to analyze the microscopic ring resonator, but this method can not be used to deal with the ring resonator in optical waveguide gyroscope, because the size of the model is too large (the radius of ring resonator is 10 mm). In this paper, an accurate method was demonstrated to design the ring resonator, in which the model was analyzed by together with the Beam Propagation Method (BPM), guided-wave optics and the theory of multiple-beam interference. In this method, the ring resonator was divided into two parts, the coupler and the bend waveguide, and the phase condition of optimum resonance was updated, the phase shift caused by the length of bend waveguide was added upon the propagation phase shift of the coupler. Parameters such as insertion loss y; coupler coefficient k; phase shift of the coupler; the propagation constant β, and the bending radiation loss of bend waveguide were obtained accurately by this method. Through the vector analysis, the intensity of resonance of the ring resonator was calculated, and the characteristics of ring resonator were shown. At the end of this paper, the optimization fabrication of optical waveguide resonator was discussed.
Machining mode and error analysis in non-axisymmetric aspheric surface grinding
Show abstract
To improve machining accuracy of non-axisymmetric lens, this paper presents the grinding mode with equal arc length feeding in parallel grinding, and analyses the relations between machining error and machining step in both equal length mode and equal arc length mode. For the same purpose, this paper also discusses the calculation of 2-axis machining path compared with 3-axis machining. Finally, the calculation and simulation of machining path are carried out to guide practical grinding.
Long wavelength infrared dual field-of-view optical system
Show abstract
For cooled 320×240 staring focal plane array (FPA), a novel long wavelength infrared dual field-of-view optical system is presented in the paper. The optical system is composed of re-imaging part and zooming part. The parameters of the system are 1.96 f/number, 100% cold shield efficiency, 180mm/60mm effective focal length (EFL) and 8-10 μm spectrum region. The optical system is analyzed from two modes of narrow field of view (NFOV) and wide field of view (WFOV). The system can be used in the temperature range from-30°Cand 60°C without significant degradation of optical performance. The final test results prove the designed performance is good..
Research on locus planning in large scale non-axisymmetric aspheric surface machining
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According to the requirement of high precision non-axisymmetric aspheric surface machining, and analyzing the locus planning limitation of traditional aspheric machining, a set of machining locus planning methods has been put forward to meet the requirement of non-axisymmetric aspheric machining. The method can minish the average and maximum value of residual error in divided area. Experiment result shows that the new machining method can fit ideal locus more, can minish machining error and improve machining accuracy more. It can get stable accuracy when the machining parameters are fixed.
Study on ITO/Ag/ITO multilayer film as the electrode of organic light-emitting diodes
Show abstract
ITO (Indium tin oxide) film has been widely used as transparent electrode for organic light-emitting diodes (OLEDs).
Higher conductibility and transparency, smoother surface morphology and higher work function are indispensable for the
fabrication of high performance OLEDs, especially for transparent and double-side devices. Therefore, it is necessary to
deposit ITO films at low temperature to protect the organic films of OLED from damaging during fabrication process. In
this work a novel transparent electrode ITO/Ag/ITO was introduced to the OLED device. This kind of transparent
electrode was used to reduce the sheet resistance of electrode and raise the performance of OLED device. By theoretical
simulation, the optimum film thickness of three organic layers was obtained. ITO and Ag films were prepared by DC
magnetron sputtering at room temperature. The transparent electrode with low sheet resistance of 6.3 Ω/sq and high
transmittance of 87% at 550 nm was achieved. OLED consisted of this multilayer film was developed. The relationship
between the thickness of Ag film and photoelectric performance of multilayer films was also discussed.
Application of media with a negative refractive index in IR and visible frequencies
Show abstract
The paper is mainly concerned with the study of negative refraction phenomenon dependent on the incident light frequency in 2D photonic crystal which consists of a hexagonal lattice of circular dielectric rods with Si. The result indicates that along with the accretion of incident light frequency, the angle of refractive light and negative refractive index in absolute terms become smaller gradually. This law offers an application of differentiating two close incident light frequencies. And a sample has been made successfully to realize negative refraction phenomenon.
Analysis of laser-induced damage threshold in dielectric optical film
Xuchuan Shang,
Ping Ma,
Jianping Hu,
et al.
Show abstract
The theory based on energy-band, which tracks free-electron in optical dielectrics, is established to describe laser-dielectrics-interaction process. The relations between damage threshold and laser frequency, band gap are investigated. Numerical analysis on SiO2-TiO2 stacks has been done. One-dimensional finite difference method is used to solve kinetic equation. The results show that the damage threshold of pure material decreases with the increase of laser frequency. And it increases with the increase of band gap.
Numerical and experimental study on SU-8 UV photolithography
Liqun Du,
Shenmiao Zhu,
Jiang Qin,
et al.
Show abstract
In this paper, the dimensional precision and tolerance of SU-8 photoresist microstructures are investigated quantitatively. An UV exposure improved model and a dimensional tolerance model based on Fresnel diffraction theory are established by considering the impact of the refractive index and absorption coefficient of SU-8 photoresist on dimensional precision of UV-photolithography. These models can be used to predict the dimension and tolerance of SU-8 photoresist microchannels, and the variation between the dimensional tolerance and the photolithographic parameters. The dimension and tolerance of SU-8 photoresist microstructure are simulated by MATLAB. Based on the UV exposure model, a simple development model was established by swelling theory, which can be used to predict the swelling trend of SU-8 photoresist during developing process. By this development model, the dimension change of SU-8 photoresist due to swelling in developing process has been researched quantitatively.
Calculation and structural analysis for the rigidity of air spindle in the single point diamond turning lathe
Show abstract
Ultra-precision machining for optical lens is a key subject in the field of modern optics machining, the focus of which is the higher demands for profile precision and surface roughness. As a kind of deterministic machining, the single point diamond turning lathe is widely used in the optical field, thus higher stabilization for the turning lathe is required with small amplitude of vibrations in a broad frequency-domain. The single point diamond turning lathe now boast its various forms both at home and abroad, and the vertical flying cutting milling style is an important branch. This kind of lathe is characterized with low guide rail velocity and main errors of this part are the alignment error of guide rail, the disturbance evolved by driving components, and the low velocity crawl. Such errors are presented as low-frequency profile error on the workpiece surface, and often relate to the guide rail velocity. The rotate speed of the spindle is higher comparatively, and the system is composed as a vibration element with mass, air-rigidity, air-damping and the periodicity impact vibration. As a result, this vibration can copy to the work piece by the tool nose in machining process, so we must manage to reduce the vibration for high machining precision. This paper is to deduce the proper dynamic parameter for reducing the spindle vibration and optimize the spindle structure via dynamic calculation for the diamond turning lathes used and bring forward the reformative idea for the lathes.
Matching the residual stress between Hafnia and silica for high reflective mirrors
Jiangchuan Hu,
Songlin Cheng,
Ping Ma,
et al.
Show abstract
The effects of coating parameters on the stress of silica coating, Hafnia coating have been studied. The aforementioned parameters are the angle of coating tooling, partial oxygen pressure during deposition. The experimental study shows that the parameters are two important parameters. To reduce the compress stress of silica, silica should be deposited at small angle of coating tooling and high partial oxygen pressure. The angle of coating tooling must be small and partial oxygen pressure must be higher still for the Hafnia coatings. According to the stress character of silica coating and Hafnia coating, the stresses are matched in a high reflection mirror. In this deposition technology, the high reflection mirrors also have high laser induce threshold. Which are satisfied the imposed requirement by power laser specifications.
Layer-by-layer assembled highly reflective optical coatings
Show abstract
Polyelectrolyte/colloidal TiO2 composite films have higher refractive index than glass, while polyelectrolyte/colloidal SiO2 composite films have lower refractive index. By using a layer-by-layer assembling technique, polyelectrolyte/TiO2 nanoparticle-λ/4-layers and polyelectrolyte/SiO2 nanoparticle-λ/4-layers were alternatively deposited onto optical fibers and microscope glass slides. In this way, λ/4-high-reflection optical coatings were fabricated.
Characterization of hydrogenated amorphous silicon thin films prepared by PECVD
Show abstract
Amorphous silicon (a-Si:H) films are prepared on K9 glass substrate by plasma enhanced chemical vapor deposition (PECVD) and the substrate temperature varies from 150 to 300 °C. The gas phase processes of pure SiH4 in PECVD system were discussed. The change of grain size and morphology was characterized by atomic force microscope morphology (AFM). The influence of substrate temperature on the growth rate and the optical band gap of Si:H film were measured by spectra ellipsometer (SE). Scanning electron microscopy (SEM) was used to make sure the measurement of film thickness by SE.
Temperature distribution and thermal stress in glass irradiated by dual CO2 lasers
Show abstract
A dual laser beams method was proposed to reduce the thermal stresses when machining glass with CO2-laser. A numerical method based on Ansys software was used to simulate temperature and thermal stresses in glass. Thermal stresses in glass with and without CO2-laser preheating have been studied. The results showed that machining glass with dual laser beams could reduce thermal stresses.
Negative refraction phenomenon dependent on wave guide width
Show abstract
Many changes of various parameters in photonic crystal cause changes of band structure and thus cause changes of light propagation through photonic crystal. The paper is mainly concerned with the study of negative refraction phenomenon dependent on wave guide width in 2D photonic crystal which consists of a hexagonal lattice of circular dielectric rods with Si. It is separately carried on the elaboration from three aspects: along with the accretion of wave guide width in photonic crystal, how the incident light frequency range in which the negative refraction phenomenon presents is changed; under identical incident light frequency, if the negative refraction phenomenon presents, then what the transformation of corresponding negative refractive index is ; if the value of refractive index of -1 is obtained, what the trend of e incident light frequency is.
Research on rheological property of magnetorheological fluid
Show abstract
The magnetorheological (MR) fluid is a new functional material. It is colloidal solution that solid grain was spread around fluid equably. It has been used in many regions for good controllable feature and mechanical feature. As for advanced optical manufacturing technology, magnetorheological finishing (MRF) was decided by the rheological property of MR fluid to a great extent. Take into account the need of MRF, the components of MR fluid were chosen, the evaluate system of rheological property of MR fluid was established. The effect on MR fluid by component scale is researched by experiments on measurement equipment. From that, the rheological property that magnetorheological fluids in the presence of an applied magnetic field and in the different shear strain rate was obtained. Meanwhile, the effect on MRF is researched by experiments on the MRF prototype machine e tool. The influence to surface quality was analyzed. The results shows that the relationship among the rheological property and the component scale of MR fluid and applying effect can be established by the theoretically analyzed and experiment research. The results provide the basis for MR fluid engineering development and engineering applications.
Crucial fabrication with rounded diamond cutting tools
Show abstract
In order to satisfy the machining of high precision components, much higher accuracies have been put forward for diamond cutting tools. From the viewpoints of fabrication and utilization of rounded diamond cutting tools, the material removal mechanism of lapped diamond surface layer is studied by lapping experiments. And also, the crucial processes for tool fabrication and re-lapping are analyzed and discussed. Moreover, the working state of lapping equipment affecting tool lapping quality is lucubrated. At the same time, the representative qualifications of rounded diamond cutting tools are defined and their assessment methods are proposed, respectively. Finally, in terms of the relationship of the removal mechanism and tool lapping quality, the lapping parameters are optimized for the fabrication of high precision diamond cutting tools. The results indicate the sharpness can be reduced to 30nm.
Morphology of femtosecond laser-induced structural changes in MgAl2O4 crystal
Show abstract
The morphology of structural changes in MgAl2O4 transparent ceramic (MATC) crystal ablated by femtosecond laser pulse has been investigated. Experiments were performed using a commercial Ti:sapphire laser system with 800 nm/50 fs and the repetition ratio of 1 kHz. The damage threshold and ablation area for MgAl2O4 transparent ceramic are investigated. The result shows that the darkening threshold and the damage threshold of MATC are measured to be 6.0×1012 W/cm2 and 2.4×1013 W/cm2, respectively. The ablated spots are examined by means of a charge coupled device (CCD) camera, scanning electron microscopy (SEM) and atom force microscopy (AFM). The infrared transmission ratio (IR transmission ratio) properties of MATC crystal ablated by femtosecond laser pulse are measured by micro-IR spectra. The result shows that the damaged area will increase linearly with the increasing energy of single pulse while will be approximate satisfied with Boltzmann distribution with the increasing number of multiple pulses. The spot ablated at optimized energy pulses (near the damage threshold energy) can improve the IR transmission ratio of MATC crystal from 82% to 86%. Furthermore, the periodic ripples about 100 nm in width and 200 nm in neighbouring ripples distance are formed on the bottom surfaces of ablation holes.
Study on laser anti-damage film of 532nm and 1064nm Nd:YAG laser
Show abstract
Anti-laser films have been used for decreasing the intensity of laser to protect human's eyes. Nd:YAG is widely used in military and industry, and its working wavelengths are 532nm and 1064nm. In this paper, we attempted to design a dense film based on a new complex material to improve manufacture efficiency. The frequency-doubling film is G|(HxL)n|A according to the working characteristics of Nd:YAG laser. H4 and SiO2 were selected in consideration of absorption, dispersion, index of refraction, mechanical robustness. x is equal to 2 by optimized the frequency-doubling film (G|(HxL)n |A).
The film is fabricated by Leybold SUSPRO-1110 full automatic vacuum coating machine, which is completed with Plasma Ion Assisted Deposition system. UV3150PC spectrophotometer was used to test the spectrum characteristics in the range of 532nm and 1064nm. The testing results showed that the transmission at 532nm and 1064nm are 0.0064% and 0.0041%, respectively. The integral transmission of visibility region is higher than 73%. We can entirely eliminate damages to eyes from Nd:YAG laser by this way.
Study on electroluminescent characteristics of two novel fluorene/carbazole copolymers
Show abstract
The electroluminescent (EL) characteristics of two novel fluorene/carbazole copolymers are reported in the paper. Four devices with different structures were fabricated. The polymeric organic thin films were prepared by spin-coating technique. The electroluminescent characteristics of devices were investigated. The results showed that the EL spectra peaks of the devices without bathocuproine (BCP) layer were all located at the region of 520 nm±5 nm, which showed that light emission came from Alq3, and polymers here played only the role as hole transporting layer (HTL). The maximum luminance of these two devices was 1831 cd/m2. The EL spectra peaks of the devices with bathocuproine (BCP) layer were almost located at 425 nm, which were consistent with the characterizing spectrum of copolymers, indicating that the polymer films were emitting layers in the device structures. Alq3 acted here only as electron transporting layer (ETL).The maximum luminance of these devices were 1416cd/m2 for PFC1 and 1208 cd/m2 for PFC2. It was concluded that the inserting of bathocuproine (BCP) layer changed the recombination zone of excitons in devices and thus changed the emitting site. These two copolymers can be used not only as alternative HTL materials, but also as promising emitting materials for blue light OLEDs.
Design and manufacture of broadband high-reflective film
Jing Zhang,
XiuHua Fu
Show abstract
High-reflection coating is a very important and representative optical film. Highly reflecting film is more and more extensive in the application of the laser,and has more and more high requests.The need of high energy and high power laser system has greatly promoted the research of high reflectance film. At present, the research strength and result of all-dielectric high-reflection coating present the acceleration tendency.
The paper is to study the film system design and manufacture of highly reflecting film that spread out a certain reflection bandwidth. (The bandwidth is 400nm-700nm. The reflectivity is bigger than or equal to 99%,and the light is vertical incidence). According to the design theory of high-reflection film , carry on the design and the making of the film.
Based on the quality of the material and application of the film, at the same time ,in consideration of the absorption and scattering of the film, choose the suitable material and special craft. Adopt OMS to monitor the films thickness in the process of manufacture, and use the Ion Assistant Deposition system to improve the structure and quality of film, increase the firm and compactness of film ,reduce the absorption. Through test again and again and unceasingly optimize the parameter, the result of measuring turns out that both ideal curve and practical curve is very similar and it attains the technological request .
High speed lapping hyperboloid by means of a lapping tool bending method
Show abstract
This paper discusses a new lapping hyperboloid method, which combines high-speed lapping technology with solid abrasives and lapping tool bending method. In this method a bending moment is acted as a lapping tool with solid abrasives, which makes it bend and form a shape on its working surface, which is similar as the generating line of workpiece surface. In lapping, the lapping tool is coaxial with the axis of hyperboloid surface of the workpiece and the lapping tool rotates around it to lap. This kind tool is used in forming lapping on a high speed lapping machine.
Influence of ambient gas on the microstructural properties of Er-doped nanocrystalline Si film fabricated by pulsed laser ablation
Show abstract
Er-doped nanocrystalline Si thin films were fabricated by pulsed laser ablation in high-purity Ar gas with different gas pressures at room temperature and post-annealing technology under different temperature in nitrogen. Scanning electron microscopy(SEM), x-ray diffraction(XRD) and Raman were employed to picture the microstructure of films. The SEM photographs showed that the morphology of film was transformed from the uniform nanoparticles in size to the web-like structure with the increase of gas pressure, which was attributed to the different collision cooling process of ablated particles. Raman and XRD spectra showed that the introduction of Ar gas could effectively improve the crystallinity degree of the samples and Si nanoparticle size could be controlled by adjusting the post-annealing temperature which was critical for improving the luminescent intensity of Er3+ ion. More uniform and higher crystallinity degree Er-doped Si thin films could be obtained at lower annealing temperature.
Optimization and test of two-dimensional birefringent low-pass filter
Show abstract
A two-dimensional system model, including the birefringent low-pass filter (BLF), was designed and a cost function was formulated. This model takes optical system into account in designing BLF. Optimization of the parameter of BLF is acquired by this new method. Best performance of BLF is realized when distance d of o light and e light is about half size of a pixel. Moreover, the relation between the optimized distance d and the cutoff frequency of ideal optical system was established. It is proved that the optimized distance d becomes smaller when the cutoff frequency of optical system increases.
Design of F-Theta lens used in laser marking machine
Show abstract
The lens, whose image height is proportional to its field view angle through introducing reasonable barrel distortion so as to scan or mark linearly is called F-theta lens. Design of F-theta lens is introduced in the paper. The design idea and method are illustrated in detail through the analysis of two systems with working area of 200×200mm2 and 500×500mm2. They're simple and compact. Both of them are composed of only three spherical lenses with two kinds of common optical glasses. Their tube length (from the front surface of the first lens to the back surface of the last one) is far less than 100mm. Remarkably, such simple lenses are able to obtain diffraction-limited focusing performances and low distortions less than 0.5 percent relative to F-Theta linear relation.
Research on polishing technology based on surface contact MRF
Zhi-li Chen,
Zhong-da Guo,
Wei-guo Liu,
et al.
Show abstract
A novel polishing technology based on surface-contact MRF is introduced. The principle, the magnetic field structure
and the mode of motion of this polishing method are described. Through development of uniform ring-like magnetic
field, the relevant mechanical device and circulatory system-delivered MRF from the magnetic field center are designed.
By using the orthogonal experimental technique on this system, the polishing experiment for the plane K9 glass of Φ 60
is carried out. The experiment result is examined on a Non-contact interferometer Taylor Surf CCI2000. It analyzed the
influence of surface roughness and material elimination quantity under the velocity of the principle axis, the intensity
of the magnetic field, the velocity of even pendulum of the magnetic pole, the distance between the work-piece and the
pole. The diagrams of surface roughness and material elimination quantity under the above craft parameter are given.
And the best craft parameter combination is obtained. It is showed by research and experiment that the roughness of the
experimental work piece can decrease to Ra 0.86nm from Ra 284.1nm in 50 min under the craft parameter. The intensity
of magnetic field 1800G, the velocity of the principle axis 490 rpm, the velocity of even pendulum of the magnetic pole
8rpm, the distance between the work-piece and the pole 1mm are all described.
Electronic trap effect of spectral sensitizing dye adsorbed on the surface of the film of silver chloride microcrystals
Show abstract
The photoelectron decay characteristic of AgCl mircrocrystals, which are adsorbed with the green-sensitive cyanine dye, has been obtained by using microwave absorption and phase-sensitive measurement technique. Combined with the absorption spectra of cubic AgCl emulsion sensitized by green-sensitive cyanine dye, the influence of green-sensitive cyanine dye adsorption at various adsorbing concentration on the surface structure of cubic AgCl microcrystals is investigated. It is found that when the concentration is less than 0.02ml(5.0mg/ml)/40g emulsion, the dye J-aggregate is not formed on the surface of silver chloride microcrystals, the surface of AgCl is decorated by the dye, the dye takes place shallow electron trap effect; when the sensitive concentration is more than 0.2ml (5.0mg/ml)/40g emulsion, the dye J-aggregate is formed on the surface of silver chloride microcrystals, the Agi+ of AgCl microcrystal surface is increased, the dye takes place the deep electron trap effect
Novel method of designing deformable polishing lap
Ziqiang Hu,
Ning Ling
Show abstract
In aspheric mirror polishing progress, the deformable polishing lap can change the lap surface to fit the surface of aspheric optical mirror. This paper presents a novel method of designing deformable polishing lap by using piezoceramics driver. The rationale of the new type deformable polishing lap is introduced. The calculation of piezoceramics driver deformation is explored and a correction of calculation formula is brought forward. A new type deformable polishing lap 110 mm in diameter was designed and built to polish the aspheric mirror. It consists of an aluminum disk which changes shape continuously under the control of 84 piezoceramics driver. The aspheric surfaces created by the new type deformable polishing lap are measured with micro displacement transducer. The results show that the new type deformable polishing lap can reshape to fit the surface of aspheric mirror and the maximal difference is less than 2um.
Micro topography of different material surface by solid abrasive lapped at high speed
Show abstract
The principle of solid abrasives lapping is that the abrasives are fixed and made into a special lapping tool; the workpiece is lapped in high speed lapping machine tool. It possesses many advantages compared with traditional low speed lapping with particulate abrasives, e.g. high machining efficiency, low machining cost, high and stable machining accuracy. So the highly efficient lapping method has been paid close attention to. This paper made a study on surface micro topography of different material by solid abrasive lapped at high speed. In experiments the lapping technique parameter is fixed, and different workpiece which are made by T10 steel, carbide, ceramic glass and alumina ceramics are lapped. The surface micro topography is measured by SEM, from the measuring result, it can be known that there is some shallow scribe on the surface of T10 steel, and the obvious plastic deformation can be observed. The SEM pictures show that there is some scribe on the surface of ceramics glass after lapped, with more magnification times many micro cracking and some plastic hump can be observed on the scribe. These scribes and humps are first cause of depressing surface quality, and these micro cracking can result in a lot of diffuse reflection on workpiece surface, it decreases the glossiness of mirror surface. On the surface of alumina ceramics there are a lot of defects, the size of such defect is more than the scribe of abrasive, it can be sure that the defect is not produced by lapping, so the material quality is an important effect fact to surface macro topography. On the surface of carbide there are a little of scribe and air cavity, and the scribe is very shallow; the defect of powder metallurgy martial is the primary reason.
1.06μM/LWIR dual band antireflection coatings for optical windows
Show abstract
1.06μm / LWIR dual band antireflection coatings were designed and prepared onto ZnSe substrate. Resonance field effects were investigated at the designing stage to improve laser damage threshold of the coatings, and films were prepared onto substrates with different surface quality and properties of the deposited films were investigated. The packing density and mechanical properties of ZnS films were improved by experiment analysis of ZnS prepared by IAD and optimization of the parameters of this technique. The technique properties of the materials dispersive absorption data based on optimized parameters were stable, and the optical property of the deposited films was improved. Films with transmittance of above 96.5% in the 7.7~10.5 μm region and 94% at 1.064 μm and laser damage threshold above 85MW/cm2 were prepared with such parameters, and the dual band AR coatings passed environmental tests specified by MIL-C-675C. The coated ZnSe windows meet with the demands of electro-optical systems, in which laser and IR works in common aperture, serviced in battlefield environment.
Crystallization of amorphous Si thin films by means of laser and thermal annealing from the viewpoint of energy
Show abstract
Amorphous Silicon (a-Si) films were prepared by pulsed laser ablation in vacuum chamber with base pressure of 2×10-4 Pa, then the a-Si deposited films were annealed by laser in vacuum chamber under different laser fluence and by heat in the electric furnace under ambient of nitrogen gas with different temperature. The crystallization of a-Si films presented similar process and results. According to similar characteristics, we analyzed the results via energy in order to control the relationship between two ways of crystallization, which may be able to help us to comprehend the mechanism of crystallization and prepare uniform-sized and symmetrical Si nanoparticles by controlling the energy accurately. This method can be readily adapted for mass production of optoelectronic devices ..
Photoelectron decay kinetics of cubic silver chloride microcrystal film adsorbing plentiful dye excited by laser
Show abstract
There will be large numbers of carriers coming into being in the interior of silver chloride microcrystals when illumination acts on it. Microwave absorption and dielectric spectrum detection technology with high temporal resolution (1ns) can detect instantaneous decay process of photoelectrons. In this work, the photoelectron decay action of spectral sensitized silver chloride emulsion is measured by microwave absorption and dielectric spectrum detection technology. By analyzing the measured results, it is found that when plentiful dye adsorb on silver chloride microcrystals film, the photoelectron decay of silver chloride emulsion becomes faster than that of pure emulsion. However it is not that the more the dye is adsorbed, the faster the photoelectron decay will be. When the adsorbed dye reaches a certain level, the photoelectron decay becomes slower than the fastest instance. Combining with photoelectron decay kinetics theory it is found that the above results are induced by two kinds of effect from dye adsorption.
Dynamics analysis of photoelectron decay in cubic AgCl microcrystals by sulfur sensitization
Show abstract
The decay curve of free photoelectron in cubic AgCl microcrystals by sulfur sensitization is obtained by microwave absorption dielectric spectrum detection technique. By comparing the free photoelectron decay curves of unsensitized and sensitized sample, we discover that sulfur sensitization centers act as shallow electron trap when sensitization time is 45min. In order to analyze the characteristics of sulfur sensitization center quantitatively, the method of the decay kinetics of photoelectron is used in this paper. We first proposed a model of sulfur-sensitized AgCl microcrystals, and then induced a series of kinetics equation. The characteristics curve of photoelectron decay is obtained by solving the kinetics equation, which is in agreement with the experimental curve. Meanwhile the concentration, trap depth and capture cross-section are obtained by computer simulation, which are 1.12ppm, 0.085eV and 1.46×10-18cm, respectively. Also a possible method to study the mechanism of sulfur sensitization from the perspective of dynamics is suggested.
STABCC: a new 3D surface topography algorithm based on contourlet transform and correlation theory
Jun Wang,
Yan Kang,
Lijun Xu
Show abstract
In machining and testing fields, 3-D surface topography evaluation is always one of the hottest study issues. Especially, in advanced integrate circuit and nanometer manufacture techniques where surface spraying and thin film plating are commonly applied for, anisotropy behavior in surface topography is rather obvious and existent 3-D surface topography evaluation is not enough in expressive force.
Based on the discussing about that the advantages and disadvantages of all existent filtering methods. The contourlet Transform (CT) which may provide tight bracing and mutliscale analysis was introduced. And a new 3-D surface topography evaluation filtering algorithm is presented. This algorithm has some excellent performances such as multiscale analysis, time-frequency-localization and multidirections. Especially, the algorithm is good at describing high dimensions data. Meanwhile, on the assumption that noise comply with Gaussian distributing, according to the theory that noise is not correlated with signal, STABCC that depress noise was designed.
The surface topography of a part was measured with WIVES. The data of measurement was processed by STABCC. Experiment result indicates that STABCC can reliably obtain benchmark of evaluation. And the surface information of measured part can be extracted and analyzed without distortion. Comparing with existent 3-D surface topography evaluation methods, STABCC is preponderant in practicality of engineering surface evaluation.
Rock fracture image acquisition and analysis
W. Wang,
Jia Zongpu,
Liwan Chen
Show abstract
As a cooperation project between Sweden and China, this paper presents: rock fracture image acquisition and analysis. Rock fracture images are acquired by using UV light illumination and visible optical illumination. To present fracture network reasonable, we set up some models to characterize the network, based on the models, we used Best fit Ferret method to auto-determine fracture zone, then, through skeleton fractures to obtain endpoints, junctions, holes, particles, and branches. Based on the new parameters and a part of common parameters, the fracture network density, porosity, connectivity and complexities can be obtained, and the fracture network is characterized. In the following, we first present a basic consideration and basic parameters for fractures (Primary study of characteristics of rock fractures), then, set up a model for fracture network analysis (Fracture network analysis), consequently to use the model to analyze fracture network with different images (Two dimensional fracture network analysis based on slices), and finally give conclusions and suggestions.
Comparison of global thresholding algorithms on rock joint images
Liwan Chen,
W. Wang,
Haijun Liao
Show abstract
The paper stresses the study that deals with thresholding applied to a special domain rather than thresholding in general, because of (a) the general problem is rather unspecified, (b) there is a greater chance of evaluating thresholding algorithms, if limiting the domain of possible images, and (c) there is the application of interest to us. The content of this paper is (1) to compare the selected eight of widely used global thresholding algorithms for eight typical rock joint images; (2) based on the comparison, to see how they work for joint images, and (3) how to choose a global thresholding algorithm to segment the joint images with a small variable background (the background is not completely uniform). In order to evaluate these global algorithms, whatever how available they are for joint images, the algorithms have been implemented into a PC computer. After comparison of these algorithms, we modified optimal and between class variance algorithms for rock joint images. which makes thresholding more reasonable.
Study on chemical mechanical polishing process of lithium niobate
Shengli Wang,
Yuling Liu,
Zhenxia Li
Show abstract
Chemical mechanical polishing of lithium niobate wafer in alkaline slurries has been investigated. In the lithium niobate CMP, the slurry was made by adding colloidal silica abrasive to de-ionized water. The effects of polishing plate speed, slurry flow rate, polishing pressure on removal rate in actual CMP process has been discussed in order to determine the optimum conditions for those parameters. The optimal slurry component is colloid SiO2, concentration SiO2:DW=1:1; KOH concentration 0.5~1.5% and surfactant 5~15ml/L. The process conditions are polishing plate speed 60rpm, polishing pressure 140KPa and slurry flow rate 120ml/min. The removal rate can reach 300nm/min and surface roughness is 0.21nm.
Embedded design on optical coherence tomography control system
Show abstract
This thesis analyzes the principle of single-mode fiber OCT system and its control signal. Then it puts forward a design thought which it integrates various signals into the embedded OCT control system. These signals include galvanometer driving signals for rapid scanning optical delay line (RSOD), high-frequency sawtooth signals for Phase Modulator, control signals for electronic control displacement platform and amplifying and filtering circuit of scanning signals. Then we design and construct an embedded OCT integrated control system which uses ARM9 processor S3C2410A as the core. The system is integrated with many wave generating circuits, driving circuit for electric control displacement platform and amplifying& filtering circuit of feedback signals. The system discards the separated OCT system structure which is made up of many general instruments and has a high cost. The result is satisfactory. Besides, we introduce embedded Linux operating system into the system. As a result, the whole system has such features as low development and production cost, excellent extensibility and strong real time control function. Experimental results show that various control signals generated by our system meet the design demand and can be applied to practical OCT system.
Study of holographic grating in porous silicon optical waveguides
Show abstract
It was found that the porosity of porous silicon has a maximum value under certain illumination intensity in our experiment. According to the experimental result, the grating was fabricated from porous silicon by controlling illumination intensity. As the refractive index of porous silicon decreases with an increase of the porosity, so the index distributing of porous silicon can be controlled by illumination intensity. A holographic process allows obtaining a mask of light on top layer during fabricating the multilayer porous silicon optical waveguides. The interference of two coherent Ar+ laser beams produces at the sample surface bright parallel lines. The porosity is modulated in the plane. The effective deep of modulation is directly related to the penetration of the illuminating beam. We have developed an experimental setup that allows guide light at 1064nm incidents vertically into the grating in porous silicon optical waveguides. The diffractive efficiency of the first order diffraction light in TE and TM polarization are measured in our experiment respectively.
Study on anti-laser high-reflection coating
Hongming Wang,
Xiuhua Fu,
Xirong Chen
Show abstract
Multi-layer dielectric high reflecting mirror is one of the important optical elements of laser. In terms of high power laser, anti-laser damage threshold value of high reflection coating which deposit on the surface of the optical component affect the life of laser system directly, so we deeply study the damage mechanism of multi-layer dielectric highly reflecting film under the exposure of laser. Choose suitable film material and adopt the manufacture method of complex film. Through multiple experiments and optimize the parameter, we find the path of improving anti-laser damage threshold value of film and the method of making high intensity film. The results of experiment and testing turn out that the film manufactured completely meets the demand of laser system used in the subject
Study on the performance of organic light-emitting diode with N,N'-bis(3-methylphenyl)-N,N'-diphenylbenzidine doped in polystyrene as hole transporting layer
Show abstract
Organic light-emitting diodes (OLEDs) with a structure of indium-tin-oxide(ITO)/N,N'-bis(3-methyl¬phenyl)-N,N'-diphenylbenzidine(TPD):polystyrene(PS)/tris(8-hydroxyquinoline)-aluminum(Alq3)/Mg:Ag were fabricated. Among them PS:TPD thin film acts as a hole transporting layer (HTL) and was prepared via dimethylbenzene solution dissolved with a mixture of PS:TPD by spin-coating method. The influence of TPD doped ratio in the mixture on the performance of device was investigated. Experimental results show that luminescent brightness of devices increase with the enhancement of TPD doped ratio, while electroluminescent spectra are not affected. In addition, lifetime of the device when the ratio of TPD to PS is 7:3 was 4 times higher than that of pure-TPD device. This phenomenon was postulated that PS enhanced the uniformity of TPD film, which was characterized by the result of atomic force microscope (AFM) analysis, and thus overcame the shortcoming of low stability of small-molecular film.
Deposition and applications of high performance YF3 thin films
Show abstract
In this work, the improvement of IAD technique to packing density of YF3 films with low absorption over the broadest spectral range, has been investigated. YF3 films were prepared by e-beam evaporation of pure YF3 with Ion Assisted Deposition, DI=0A, 0.8A, 1.0A, 1.2A, (DI is the drive current during deposition of the YF3 films). The packing density of films is inspected generally by water and salt water soak test. The optical properties of all samples were measured and analyzed before and after soak test. The calculation of optical constants for different samples is based on spectrum cures. By comparing the varieties of refractive index and extinction coefficient of different samples, we have found the ideal process parameters of deposition for YF3 film. Then, the 3~5 μm and/or 8-11.5 μm infrared antireflective coatings have been fabricated by using the process parameters of deposition YF3. All samples passed MIL-F-48616 environmental tests and meet with the application demands of military optoelectric equipment.
Design and fabrication of soft x-ray transmission phase gratings
Show abstract
A binary transmission phase grating is designed to operate as a dispersive element used in soft x-ray plasma diagnostic in ICF (inertial confinement fusion). The first and zero orders diffraction efficiency is simulated as a function of wave length and grating thickness. It is shown that the first order diffraction efficiency of a transmission phase grating can be up to 23.3% of the incident light, whereas that is not more than 10% for a conventional amplitude transmission grating. The transmission phase grating is fabricated in gold film supported by polyimide membranes using holography and ion beam etching method. The primary experimental results are presented.
Design of erbium-doped fiber laser based on linear multi-cavity
Hua-wei Pang,
Hui-min Cui,
Hua Lian,
et al.
Show abstract
An erbium-doped fiber laser with a novel cavity--linear multi-cavity is proposed. It is different from a linear single-cavity and a ring-cavity used in fiber laser before. Based on the character of erbium-doped fiber gain at 1550 nm, a laser diode radiated at 980 nm and acted as the pumping source, an erbium-doped fiber employed as gain medium and the linear multi-cavity used as selector, a linear multi-cavity erbium-doped fiber laser radiated at 1558.2 nm is demonstrated with an output power of 10.04dBm and a bandwidth of 0.2 nm under 80 mw power of pump laser. thin addition, the theory of linear multi-cavity erbium-doped fiber laser was discussed in detail.The factors that influences the stability of the output power of fiber laser were analyzed theoretically. Examination results are used for reference to research..
DLC/BP ultra durable LWIR protective coatings for ZnS windows
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DLC/BP ultra durable LWIR (long wave infrared) protective coatings have been designed and prepared on ZnS (Zinc Sulphide) windows successfully. Both of BP and DLC coatings are deposited by RF-PECVD (radio frequency enhanced plasma chemical vapor deposition) process, but in different chamber. The transmittance, micro-hardness and durability of DLC/BP coatings have been investigated, which are measured by FTIR spectroscopy, micro-hardness tester and simulative harsh environmental test system. The ZnS window outer face coated with DLC/BP coatings and inner face coated with high efficient antireflection coatings is also fabricated. In the band of 8~11.5μm, the measured maximum transmittance is above 93% and the average transmittance is about 89%. The coated ZnS windows meet with the demands of LWIR electro-optics systems workable in battlefield environment.
Design of dual-FOV refractive/diffractive LWIR optical system
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An infrared-optical zoom system using binary element is proposed in this paper. The two main advantages of the zoom system introducing here are: bigger F-number and lower cost. The primary optical properties are: F/#=1,zoom ratio =1:4,and dual field are 26.6°and 5.6°respectively. Wider field of view is used for search and the smaller one is used for imaging details. This system uses un-cooled infrared detector with 320×240 pixels and 45μm pixel size. The F-number matches the sensitivity range of the detector array. Three aspects are considered during design process to make the system more satisfactory and more achievable. First, the manner of zoom is accomplished by exchanging tow lenses into the smaller field of view system layout. The lens exchange manner faces the requirement of simple system structure and good image quality in both focal points. It can also make the system more feasible in the alignment process than mechanical-zooming manner and optical-zooming manner; Second, binary element is used to correct the chromatical aberration by taking the advantage of negative dispersion characteristics and the cost of the system is lower than that of conventional ones with Zinc Selenide (Znse) material at the same level. In the binary element is rotational symmetric with one step which is easy to fabricate; Others, in order to balance 5th spherical aberration, 5th coma aberration and 5th astigmatic aberration, high-order asphere surfaces with 2th order to 10thorder are also hired in the system. Asphere surface is useful in compressing the system and improving optical system transmittance. This kind asphere surface is on industrial level featuring low cost and easy to fabricate. It is shown that good image quality can achieved by implementing five Germanium lenses and the transmittance of system is 72%. All aberrations are diffraction-limited, both spherical aberration and astigmatic aberration are corrected. When the field of view(FOV) is 26.6°and the focal length is 152mm, MTF at Nyquist frequency(11lp/mm) is great than 0.7. The spherical aberration is -0.0073. The coma aberration is 0.0978 and the astigmatic aberration is -0.013. When the field of view(FOV) is 5.6°and the focal length is 38mm, MTF at Nyquist frequency is great than 0.8 with spherical aberration -0.0046,the coma aberration 0.055 and astigmatic aberration 0.034.
Effects on residual stresses of aluminum alloy LC4 by laser shock processing
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The influences of processing parameters on laser-induced shock waves in metal components are discussed and analyzed. The effects of different parameters of laser shock processing (LSP) on residual stress of aerospace aluminum alloy LC4 were investigated. LSP was performed by using an Nd: glass phosphate laser with 23 ns pulse width and up to ~45 J pulse energy at power densities above GW/mm-2. Special attention is paid to the residual stresses from laser shock processing. Modification of microstructure, surface morphology by laser shock processing is also discussed. Results to date indicate that laser shock processing has great potential as a means of improving the mechanical performance of components.
Fabrication of supersmooth surfaces with low subsurface damage
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To produce super-smooth optical surfaces with extreme low subsurface damage (SSD) is still a challenge in optical fabrication. A systemic method is designed to get the low damage super-smooth surfaces in this paper. By taking the fabrication of supersmooth surfaces as a chain, careful attention is given to each key node of samples fabrication process, the grinding, fine grinding and polishing. Thus the irremovable defects on the surface and subsurface are minished. And then two kinds of samples are prepared. Some are superpolished by the bowl-feed polishing process directly, and the others are chemically etched to remove μm-scale residual subsurface layer at first. Similarly, a bowl-feed polishing process is adopted to produce the super-smooth surfaces. The qualities of suptersmooth surface without etching process and super-smooth surface after etching are discussed in terms of top surface roughness (TSR), subsurface damage (SSD). Comparison of the two surfaces indicates that the designed systemic method to remove of subsurface damage can perform effectively; the SSD depth decreases by approximately a factor of 3.6 while the roughness makes a slight progress. In addition, a nondestructive method, quasi-Brewster angle technology (qBAT), of measuring the SSD is introduced and the correlation between the surface characteristics and the optical phenomena at the Brewster angle is also established.
High quality HfO2 thin films prepared by reactive ion beam assisted deposition
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HfO2 films have been deposited with electron beam evaporation of oxide hafnium, reactive evaporation (RE) and reactive ion beam assisted deposition (RIBAD). The optical and structural properties and laser-induced damage threshold of the films have been studied. It was found that HfO2 film deposited with RE has less defects and good uniformity. In addition, the samples deposited with RIBAD have higher refraction index, and can reduce the absorption at a certain condition. Laser-induced damage (LIDT) is under improvement. The crystal structure of the sample deposited with RIBAD is monoclinic, and when the bombardment energy raises, the preferred orientation changes from (002) to (-111).
Research on ITO transparent electromagnetic shielding coatings for E-O system
Mi Zhu,
Changxin Xiong,
Qiantao Lee
Show abstract
The key factors, which affect the shield effectiveness of ITO transparent conductive coating, have been analyzed in the paper. All the coatings are deposited on K9 glass substrates by electron beam evaporation technology and ion-assistant deposition (IAD) technique. And the relationships between visible transmittance, sheet resistance and shield effectiveness (reflectivity of microwave ) in 2~18GHz range have been investigated.
Two kinds of electromagnetic shielding coatings have been developed. One is single-layer electromagnetic shielding coating, which is ITO coating only. The other is multi-layer electromagnetic shielding coating, which is ITO with matched antireflection coatings.
The performance of electromagnetic shielding coatings is as follows: average transmittance from 425 to 675nm is 83% for the K9 substrate with the single layer electromagnetic shielding coating only, and average transmittance is 88% for the substrate with the back surface antireflection coating. Average transmittance from 425 to 675nm is 88% for the substrate with the multi-layer electromagnetic shielding coating and average transmittance is 94% for the substrate with the back surface AR coating. The average reflectivity of perpendicularly incident microwave of the best coating sample is not lower than -1.5dB, for which the frequency band is from 2GHz to 18GHz. According to MIL-675C environmental stability standards, environmental and physical durability test results, including thermal cycling test, humidity test, moderate abrasion test and salt spray fog test, etc, are also in detail presented in the paper.
Low doping white phosphorescent organic light-emitting diodes
Yadong Jiang,
Jun Wang,
Shuangling Lou,
et al.
Show abstract
Efficient white organic light-emitting diodes (OLEDs) based on a novel phosphorescent material (t-bt)2Ir(acac) with a structure ITO/CuPc (15 nm)/NPB (15 nm)/CBP : (t-bt)2Ir(acac) (30 nm, x%)/ BCP (20 nm)/Alq (20 nm)/LiF (1 nm)/Al (100 nm) were fabricated. (t-bt)2Ir(acac) lightly doped in a host material CBP was used as a yellow emitting layer and fluorescent material NPB was used as a blue emitting layer as well as a conventional hole transporting material. Low doping concentration (1%) device showing white light emission from 6 V to 14 V has a maximum efficiency 1.6 lm/W at 8 V and a maximum luminance of 4360 cd/m2 at 13 V. High doping concentration (2% and 5%) devices emit strong yellow light under low bias and change to white light emission above 10 V bias although they show higher efficiency and luminance than 1% doping concentration device.
Laser cutting for slotted oil pipes
Changyu He
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Based on a general laser-cutting machine, a specialized laser cutting system for oil slotted pipe had been made. The effectiveness of this system to resolve the problem of focus point drifting in large range laser processing has been discussed and analyzed. Relative cooling devices and control system are also developed.
Light extraction from organic light emitting diode
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Organic light emitting diodes (OLEDs) have attracted much attention for several applications, such as light source and display. It is of both commercial and scientific interests to improve external quantum efficiency of such light emitters. The external quantum efficiency of OLED is determined by the combination of charge balance, singlet-triplet ratio and light extraction efficiency. Application of phosphorescent emitting materials can produce internal quantum efficiency very close to theoretical limitation. However, due to the refractive index mismatch between air and organic emitting layer, most of the emitted light is lost through total internal reflection into substrate and indium-tin-oxide (ITO) waveguiding modes and to self-absorption. Therefore, there is a large space for improvement on the extraction efficiency of the devices. In this paper, A Monte Carlo simulation of external emitted light has been developed. The light extraction factor for planar OLED is 17.17%. This result demonstrates that the light extraction from planar OLEDs can be quantitatively modeled by a simple ray-tracing algorithm. Microlens arrays are introduced on glass substrates to suppress waveguiding loss in the substrate. In this work, we propose to use an etched glass master for fabricating microlens. The glass master is fabricated using a simple wet etching method. A photoresist/Cr/ITO multiplayer mask is made by lithography on the glass substrate and then the glass substrate is etched with HF/HCl solution for improving the quality of generated surface. The isotropic etching profile of the glass master is utilized for microlens replication. Lens arrays are replicated on polymer (PDMS) substrates. With the use of microlens arrays, the light extraction factor is increased experimentally, without detrimental effect to the electrical performance of the OLED.
Bright-yellow molecular organic light-emitting diodes based on two novel silole derivatives
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High-efficient molecular organic light-emitting diodes using two novel silole derivatives as emitter is reported in the paper. Multilayer organic light-emitting diodes with a structure of indium tin oxide(ITO)/N, N'-bis- (1-naphthyl)-N,N'-biphenyl-1,1'-biphenyl-4,4'-diamine (NPB)/2,5-bis(9,9-dimethyl-9H-fluorene-2-yl)-1,1,3,4-tera-phenylsilole (DMFPSi)/tri-(8-hydroxyquinoline)- aluminum (Alq3)/Mg:Ag and ITO/NPB/2,5-bis(thiophene-2-yl)--1,1,3,4-tetraphenyl-1H-silole (BTTPSi)/Alq3/Mg:Ag have been fabricated, where Alq3 was used as an electron transport layer. These two silole derivatives have similar backbone, so EL properties are parallelly characterized. Luminance-voltage and current density-voltage characteristics of both devices were investigated and device performances were discussed. Experimental results demonstrate that the devices consisting of DMFPSi and BTTPSi with high efficiency of yellow light emission, and the maximum luminance of 16,000 cd/m2 at bias voltage of 12.5 V and 12,500 cd/m2 at bias voltage of 16.5 V, can be respectively achieved. The maximum luminance efficiencies of 2.35 lm/W at 625 cd/m2 for DMFPSi and 0.5 lm/W at 4000 cd/m2 for BTTPSi are obtained. The peak of EL spectrum locates at 555 and 580 nm, respectively, which are independent of the variation of bias voltage.
Properties of DC magnetron sputtered indium-tin oxide films with the assistance of tiny H2O vapor at low temperature
Hui Lin,
Junsheng Yu,
Shuangling Lou,
et al.
Show abstract
ITO thin films with high optical and electrical performance were prepared by DC magnetron sputtering method with the
assistance of tiny H2O vapor during deposition process. ITO films were deposited in a custom built Sunicel Plus200 DC
magnetron sputtering system using argon as the main sputtering gas and a small quantity of H2O vapor. For the
characterization of ITO film properties, film thickness was measured with a step profiler. The 3D-images of the ITO film
surface were characterized by an atomic force microscope (AFM). Film square resistivity was estimated by four-point
probe method, and optical transparency was measured by a spectrophotometer. The resulting ITO films exhibited high
electrical conductivity as well as high optical transparency and smooth surface morphology. The square resistivity was
about 50 Ω/square area sputtered at 200 W at the substrate temperature of 100°C on the position of 10 cm from the
sputtering source to substrate center. With the introducing of 2×10-5 Torr H2O vapor during sputtering process the visible
light transmittance of approximately 89% in the visible spectral region was achieved.
High bright blue organic light-emitting diodes based on a novel silole derivative
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A high performance blue organci light-emitting diode (OLED) using a silole derivative as emitter has been fabricated by vacuum thermal evaporation method. The triple-layer device structure is indium tin oxide (ITO)/N, N'-diphenyl-N,N'-bis (3-methylphenyl)-1,1'-biphenyl-4,4'-diamine (NPB) (50 nm)/1,2-bis(1-methyl-2,3,4,5-tetra-phenyl-1H-Silole-1-yl)ethane (BMPSiE) (40 nm)/tris (8-hydroxyquinolinolato) aluminum (Alq3) (10 nm)/Mg : Ag(100 nm 10:1), where BMPSiE was employed as an emitting layer (EML), NPB and Alq3 act as hole transporting layer (HTL) and electron transporting layer (ETL), respectively. Experimental results demonstrate that the device consisting of novel emissive material has a maximum luminance of 13500 cd/m2 and a current density of 1520 mA/cm2 at a bias voltage of 20 V.The peak of electroluminescent spectrum locates at 483 nm which well accord with the photoluminescence results. The Commissions International de l'Eclairage (CIE) coordinates locate at (0.20, 0.33), which are independent of the variation of forward bias.
Methods to determine best-fit sphere for off-axis aspheric surface
Li-xin Zheng,
Zheng Zhu
Show abstract
In this paper we present an approach which can calculate the radius R of best-fit sphere in optical replication of off-axis aspheric surface. For regular shape, we choose the marginal points as constraint condition to get the radius R of best-fit sphere, which satisfies the root mean square of asphericity minimal. The aspheric rms under different constraints can be compared on the condition that the optical parameters, such as the paraxial radius R0 and conic constant k, are same for the parent aspheric surface of the circle, sector and regular hexagon-shaped off-axis aspheric surfaces. Moreover, we used the Golden Section Method and Cyclic Coordinate Method for optimization to solve the rms, and analyze the constraint conditions for the best-fit spheres.
Colony image acquisition and segmentation
W. X. Wang
Show abstract
For counting of both colonies and plaques, there is a large number of applications including food, dairy, beverages, hygiene, environmental monitoring, water, toxicology, sterility testing, AMES testing, pharmaceuticals, paints, sterile fluids and fungal contamination. Recently, many researchers and developers have made efforts for this kind of systems. By investigation, some existing systems have some problems. The main problems are image acquisition and image segmentation. In order to acquire colony images with good quality, an illumination box was constructed as: the box includes front lightning and back lightning, which can be selected by users based on properties of colony dishes. With the illumination box, lightning can be uniform; colony dish can be put in the same place every time, which make image processing easy. The developed colony image segmentation algorithm consists of the sub-algorithms: (1) image classification; (2) image processing; and (3) colony delineation. The colony delineation algorithm main contain: the procedures based on grey level similarity, on boundary tracing, on shape information and colony excluding. In addition, a number of algorithms are developed for colony analysis. The system has been tested and satisfactory.
Design and implementation of lens for fast biochip detection system
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Raising the scanning speed of a detection system is indispensable for practical applications of biochips such as fast clinical diagnoses and high-throughput filtration. Compared with PMT-based confocal scanning system, CCD-based one can afford simultaneous illumination and detection of multiple pixels with high speed. The performance of imaging lens system plays an important role in CCD-based fluorescence collection and imaging systems. The sensitivity, speed and resolution of the detection system are controlled by numerical aperture, field and aberration of lens system respectively. One of the key technologies of fast biochip detection system refers to the design of the imaging lens system. In this paper, the main characteristics of CCD-based fluorescence collection and imaging system are analyzed in detail, and an imaging lens system is designed to meet the requirements of fast scanning. An optical design software ZEMAX is applied to design and optimize the imaging lens system. The system parameters such as modulation transfer function and field curvature and distortion are obtained. The imaging of standard biochip samples with cyanine (CY5) dye dots on glass substrates are realized by our manufactured lens system. Results show that our lens system is suitable for biochip scanning system with high speed and high sensitivity. Its system parameters are as: numerical aperture for 0.52, viewing field for 10 mm, working distance for 22.5 mm, spatial resolution for 10um and small aberrations. The limitations of the imaging lens system and the routes for further improvement are discussed.
Grating vibration sensor with digital direction identification
Jingchang Zhuge,
Zhoumo Zeng,
Shuqing Li,
et al.
Show abstract
In this paper, a new method of direction identification in digital signal processing for seismic wave is introduced. Traditional direction identification method is replaced by a new digital direction identification method without making use of direction identification circuit. For judging whether the direction of vibration changes or not, the relative differences of the amplitude ratio and frequency change of Moire fringe signals at the turning points are two main determining conditions. According to the characteristics of current Moire fringe signals, we can predict the range of relative differences of the amplitude ratio and frequency change of Moire fringe signals at the next turning point. If the Moire fringe signals satisfy any one of two conditions, the possibility of vibration direction changed is extremely large. In order to avoid misinformation, the determination of vibration direction will be made after the confirmation process. Once the change of vibration direction is determined, the turning point will be picked out accurately. Experiments result shows that the solution has advantages of high resolution, high precision, wide dynamic range and low error.
All-fiber acousto-optic intensity modulator using surface acoustic wave
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In this paper, a fiber coupled-mode equation between front-wave and back-wave of optical guided modes with micro disturbance is given from parameter interaction equation. Considering surface acoustic wave (SAW) as the micro disturbance, a coupled-wave equation group of SAW all-fiber acousto-optic (AO) effect is deduced. The equation group includes front-wave equation and back-wave equation. A back-wave efficiency formula is demonstrated through solving the equation group. It is proved, that the back-wave efficiency is directly proportional to power of the SAW under condition of weak AO interaction. Quartz crystal is considered as the best base crystal. It is because acoustic impedances of the quartz crystal and the fiber are equal approximately. According to form of SAW basic equations or Christofell equations the best SAW mode of the quartz is determined. All-fiber AO intensity modulator using SAW is designed and manufactured. Modulation curve of optic power of the back-wave vs power of electric signals driving the device is measured. The experimental results indicate, optic power of the back-wave is directly proportional to power of electric signals driving the device. The experimental results are consistent with the theory. Advantages of the device are smaller volumes, less energy consumes, less inset-losses and so on. Besides, it is easy to integration and can be used in optic fiber communication.
Ion beam figuring system in NUDT
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Ion beam figuring (IBF) is an optical fabrication technique that provides highly deterministic process to correct surface figure error of previously polished surfaces by using a directed, inert and neutralized ion beam to physically sputter material from the optic surface. Recently, an ion beam figuring system KDIFS-500 has been designed and built in National University of Defense Technology (NUDT) of the P.R. China. KDIFS-500 is capable of processing workpiece up to Φ500mm. Line scanning process was discussed in detail for estimating the parameters of the beam removal function (BRF) in process. Experiments were conducted to demonstrate that the BRF increases gradually in process and by employing a stability control, the BRF can be kept stable in process. Finally, a Φ95 mm plano optical sample of CVD coated SiC substrate has been figured in two process iterations for demonstrating the correction capability of the KDIFS-500. Their figure convergence ratios reached 5.8 and 2.1 respectively. The actual figure residual errors were basically consistent with the predicted error. These consistencies indicated that the IBF processes on KDIFS-500 are predictable deterministic processes.
ZnO nanocrystalline thin films prepared by ion beam enhanced deposition method
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In-N codoped ZnO nanocrystalline films were prepared on Si and glass substrates by Ion beam enhanced deposition method. The In-N codoped ZnO nanocrystalline films deposited on Si substrates are found to have a preferred (002) orientation, smooth surface and high density. P-type ZnO thin films were obtained. Room temperature photoluminescence measurements indicated that the ZnO nanocrystalline films had two UV emission peaks and several visible emission peaks.
Hardness of CNx films deposited by MCECR plasma sputtering
Changlong Cai,
Junpeng Li,
Qian Mi,
et al.
Show abstract
The CNx (carbon nitride) films were deposited on silicon (100) with Mirror-Confinement-type Electron Cyclotron Resonance (MCECR) plasma sputtering method, which sputters pure carbon target with the Ar/N2 plasma. The thickness of CNx films was about 80nm. In this paper, the hardness of CNx films was investigated, and it is measured by the nanoindenter. The technical parameters of MCECR plasma sputtering influencing the hardness of CNx films include the substrate bias, microwave power, target voltage, gas pressure, and the Ar/N2 ratio. Results shown that, the hardness of CNx films is bigger, when the substrate bias is at +30V, the microwave power is 200W, the target voltage is +500V, the gas pressure is 2×10-2Pa, and the Ar/N2 ratio is 9/1.
Hardness of DLC deposited by pulsed arc
Changlong Cai,
Qian Mi,
Weihong Ma,
et al.
Show abstract
Diamond-like carbon (DLC) films were deposited by means of pulsed vacuum arc ion source, and its hardness was measured using the HXD-1000 digital micro-hardness tester. Measurement results show that, substrate temperature, main loop voltage, pre-cleaning time, and pulse frequency influence hardness of DLC films. The relationships of hardness of DLC with these parameters were presented and the reasons were discussed in this paper, from these, an optimum DLC deposition technique by means of pulsed vacuum arc ion source was presented. The hardness of DLC films can be up to 25.36Gpa when the substrate temperature is 100°C, the pre-cleaning time is 30 min, the pulse frequency is 3Hz, the substrate angle is 45°;, and the main loop voltage is 200V.
Optical passive athermalization for infrared zoom system
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In an infrared zoom system, it is difficult to obtain the best thermal compensation for all effective focal length (EFL) simultaneously by moving a single lens group. According to the principle of optical passive athermalization, the equations of focal length, achromatization and athermalization of both long and short EFL are established respectively. By analyzing the thermal aberration value relations between long EFL and short EFL, the thermal aberration values of the switching groups for short EFL athermalization are calculated. Firstly, the athermalization of long EFL is designed. Then through reasonable optical materials matching of the switching groups, the short EFL achieves athermalization as well.
In this paper, a re-imaging switching zoom system is designed. It has a relative aperture of f/4.0, 100% cold shield efficiency, the EFL of 180mm/30mm at 3.7-4.8μm. The long EFL includes four refractive elements and one hybrid refractive/diffractive element. The switching groups of short EFL have two types, one is composed of four refractive elements, and the other is composed of two refractive elements and one hybrid refractive/diffractive element. Both of the short EFL achieve athermalization. With the aluminum materials of system structures, the zoom system achieves optical passive athermalization. It has the diffraction limited image quality and stable image plane from -30°C to 70°C.
Design of Cassegrain-Schmidt optical system
Peiming Hao,
Kexin Li,
Zhengting Wang
Show abstract
The image plane of Newton-Schmidt system is between Schmidt corrector and spheric mirror, which is difficult to be received. Cassegrain-Schmidt system is put forward to shift the image plane behind the primary mirror1. Based on the third order aberration theory and Gaussian formula, and choices of defocus Δ and neutral zone hn, new parameters obscuration ratio of two Cassegrain α mirrors and magnification of the secondary mirror β and concentric condition of two Cassegrain mirrors, the equation of corrector including the 2nd and 4th order terms of the even aspheric plate is established. Then the 4th, 6th and 8th order terms of Schmidt corrector plate are solved by inverse-ray tracing to correct high order spherical aberration. To reduce chromatic aberration of Cassegrain-Schmidt system, new types of achromatic Cassegrain-Schmidt systems are put forward and discussed.
Design and application of non-spherical focus mirror based on analytical function theory
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According to the mode and focus characteristic of the laser beam, a laser focus mirror is developed based on the designing principle and method of analytical function non-spherical focus mirror(ANSFM), its designing and focus characteristic is analyzed systematically. The result indicated: With this design technique, numerous iterations and experienced parameters are not needed, comparing with the designing of high order multinomial non-spherical focus mirrors(HONSFM). Once the focal length f ,diameter D and refraction index n of mirror material are known, the analytical non-spherical focus mirror can be obtained accurately and fast. The designed mirror has flat surface and large machine tolerance, which makes it easy to be manufactured and tested. The focusing spot diameter(FSD) of the designed mirror is φ11.4μm for a parallel beam. The experimental results show that FSDANSFMHONSFM
1.8-in. 128x160 full color passive matrix OLED
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A 1.8-in. high-resolution passive matrix OLED (PMOLED) display panel has been successfully developed. We design the structure of full color PMOLED device. We pattern the device on a 128×3×160 pixel area, 384 row ITO anodes and 160 column cathode separators on ITO glass developed by us through photolithograph process. We have successfully fabricated the 1.8-in. 128×160 full color passive OLED display panel through our SUNICEL PLUS 200 OLED systems. The structure of OLED is a double-hetero structure. It has the device structure of ITO/2TNATA/NPB/ Alq3+C545T/Alq3/LiF/Al for green, ITO/2TNATA/ NPB/Alq3+Rubrene+DCJTB/ Alq3/LiF/Al for red, ITO/2TNATA/
NPB/EB43+TBPE/Alq3/LiF/Al for blue. The PMOLED display panel has full color emission with a resolution of 128×160, and the brightness of 200 cd/m2, as well as the lifetime of 5000 hours. The open aperture ratio of each pixel is 45%.
Cleaning of ITO glass with carbon dioxide snow jet spray
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ITO glass cleaning is LCD, OLED and other flat panel display industry's key technologies. At present, the usual wet cleaning technology consumes large amount of water and chemicals, and produces a large amount of contaminant venting. CO2 snow jet spray cleaning has been successfully applied to cleaning the surface of semiconductor chip, vacuum devices and space telescopes. Surface cleaning of indium tin oxide (ITO) film was carried out with carbon dioxide snow jet treatment .Based on the measurements of the contact angles, X-ray photoelectron spectroscopy and scanning electron microscopy (SEM) ,the influence of carbon dioxide snow jet treatment on surface cleaning of indium tin Oxide film was investigated and compared with the samples of low frequency immersion ultrasonic cleaning. Experimental data show that the carbon dioxide snow jet treatment effectively removes particulate and hydrocarbon on ITO surface.
Study on the spectral properties of Yb:KGW crystal
Wenqin Yang,
Ji Wu,
Lihua Guo,
et al.
Show abstract
The absorption and fluorescent spectra for 5at.%Yb3+ doped KGW crystal which is cut and polished along the crystal axis at room temperature are presented in the paper. The absorption cross section stimulated emission cross section and fluorescence time were calculated with reciprocity method. It is well know that Yb:KGW is a double axes crystal, its a, b and c axes are not perpendicularly cross with each other. So it is not easy to immediately find out its optical polarization effect. To investigate spectral polarization property, a sample of Yb:KGW cut along its main axis of refractive index was used. There were quite different from each other for every ch setting. However, when the pumping light (~980nm) is polarized in the refractive index main axis Np (i.e. E||Np) and propagates along the other refractive index main axis Ng, the most intensive absorption and fluorescence (1025nm) will be obtained.
Optical system design of multi-spectral and large format color CCD aerial photogrammetric camera
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Multi-spectrum and high spatial resolution is the vital problem for optical design of aerial photogrammetric camera all the time. It is difficult to obtain an outstanding optical system with high modulation transfer function (MTF) as a result of wide band. At the same time, for acquiring high qualified image, chromatic distortion in optical system must be expected to be controlled below 0.5 pixels; it is a trouble thing because of wide field and multi-spectrum. In this paper, MTF and band of the system are analyzed. A Russar type photogrammetric objective is chosen as the basic optical structure. A novel optical system is presented to solve the problem. The new optical photogrammetric system, which consists of panchromatic optical system and chromatic optical system, is designed. The panchromatic optical system, which can obtain panchromatic image, makes up of a 9k×9k large format CCD and high-accuracy photographic objective len, its focal length is 69.83mm, field angle is 60°×60°, the size of CCD pixels is 8.75um×8.75um, spectral scope is from 0.43um to 0.74um, modulation transfer function is all above 0.4 in whole field when spatial frequency is at 60lp/mm, distortion is less than 0.007%. In a chromatic optical system, three 2k×2k array CCDs combine individually three same photographic objectives, the high resolution chromatic image is acquired by the synthesis of red, green, blue image data information delivered by three CCD sensors. For the chromatic system, their focal length is 24.83mm and they have the same spectral range of 0.39um to 0.74um. A difference is that they are coated in different film on their protect glass. The pixel number is 2048 × 2048; its MTF exceeds 0.4 in full field when spatial frequency is 30lp/mm. The advantages of digital aerial photogrammetric camera comparison with traditional film camera are described. It is considered that the two development trends on digital aerial photogrammetric camera are high-spectral resolution and high-spatial resolution. Merits of the aerial photogrammetric camera are multi-spectral, high resolution, low distortion and light-weight and wide field. It can apply in aerial photography and remote sense in place of traditional film camera. After put on trial and analyzing from the design results, the system can meet large scale aerial survey.
Scaling and analyzing the influence of fluid surface of fluid with nano-granular through speckle pattern experiment
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An optical system with double beam interference system was designed to measure the movement of nano-particles in fluid with laser speckle technology. In order to investigate the influence of the scattering light generated from liquid surface on speckle patterns, the liquid surface contour was dynamically detected by WYKO during nano-particle movement. The result demonstrates that the fluctuation of fluid surface is slight. Meanwhile, in order to further analyze this effect, a piece of ground glass was employed. The process of ground glass to be polished to optical glass was studied and tested continuously using WYKO and laser speckle technology. And then, the speckle patterns generated from kerosene fluid surface were studied.
By contrast, the results show that, the fluid surface is transparent to the measurement wavelength. The influence of the surface of fluid can be neglected. Furthermore, the conclusion illustrates that laser speckle technique is an effective and reliable method to study the movement of nano-granular in fluid.
Optical and electrochemical properties of Ni doped WO3-MoO3 films prepared by sol-gel process
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The electrochromic effect, change of optical transmittance with respect to the applied DC voltage,is a well-known phenomenon. The electrochromic film can be fabricated with various methods such as rf and dc sputtering, chemical vapour deposition, electron, thermal and ion cluster beams and several other methods. Sol-gel process offeres several advantages over conventional deposition method for the control of stoichiometry and film structure. It was known that WO3 thin film doped with niobium and with Lithium exhibits a well bleaching process as compared with pure tungsten oxide film [1-4]. The presence of Li, Ta, Ti and Nb in WO3 film improves the spectroelectrochemical response of these materials. So in this paper, we presented a mixed-metal oxide sol-gel synthesis, deposition, optical and electrochromic performances of Nickel (II) acetate doped tungsten molybdenum oxide film WO3-MoO3--Ni(CH3COO)2. The range of dopant concentration was 0.75ml-7.5ml V%. Film made from WO3-MoO3 precursor solutions was also used for comparison. The film has been studied and characterized by ultraviolet-visible spectroscopy, X-ray diffractometry (XRD), scanning electron microscopy (SEM) and electrochemistric station. The good coloring and bleaching behaviors of doped Ni film mean that they are suitable for electrochromic material.
Narcissus analysis for cooled staring IR system
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Narcissus can have a deleterious effect on image quality for cooled infrared imaging systems. Therefore, analysis of narcissus is important for designing both scanning and staring optics. Narcissus is generally assumed to be negligible in staring IR optical designs because the shading effects can be removed by calibration of the detector array data. However, the calibration usually decreases sensitiveness of the system and Narcissus variation may be noticeable for sensors when the conditions changes as follows: 1. warming and cooling the optical housing, 2. zooming optical elements, 3. movement of lenses for focus. In that case, it will result in shading and other image defects even after calibration. To minimize these effects, narcissus should be assessed and controlled during the design of staring array IR system. We provided a direct and fast method for analyzing the narcissus variation in the presence of software such as LightTools, TracePro and ASAP, and proposed the principles in optical design of staring IR systems to reduce narcissus. A cooled staring IR system with serious narcissus was estimated and reoptimized. Narcissus analysis of this IR system confirmed the efficiency of the analysis method.
Study on computer controlled polishing machine with small air bag tool
Yi Wang,
Ying Ni,
Jing-chi Yu
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Laser and infrared optical technologies are developed quickly recently. Small aspheric lens of φ30 to 100mm which are normally used in such optical systems are largely demanded. But computer controlled polishing technology for small batch-quantity aspheric lens is a bottle-neck technology to prevent the development of laser and infrared optical technologies. In this article, the technology of computer controlled optical surfacing (CCOS) was used to solve the problems of batch-quantity aspheric lens' polishing. First, material's removing action by computer controlled small polishing tool is detailed simulated by computer. Then, According to the simulation result, polishing correction is completed after adjusting the function of tool's resident time. Finally the accuracy of 70 mm aspheric lens (Surface shape measurement value is 0.45μm, roughness measurement value is 2.687nm) is achieved under efficient polishing with our home made model computer controlled polishing machine which has three universal driving shafts. Efficiency of small aspheric lens' batch-quantity manufacturing is remarkably improved.
Fabrication of aspherical liquid lens controlled by electrostatic force
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Aspherical micro lens is becoming more and more important due to their excellent optical quality. A novel method for fabricating aspherical liquid lens from UV curable polymer with on-line measurement is proposed. Electrostatic forces are employed to manipulate the shape of liquid polymer lens. Surface profile distortion of the liquid lens results in its focus variability. An experimental system which can fabricate tunable aspherical liquid lens and real-time detect its surface profile and focal spot is developed. The MTF of the liquid lens is calculated via detecting the lens profile image, polynomial fitting and ray tracing. The experiment system can also image the focal spot of the liquid lens and calculate its PSF. These provide a novel method for the control of the pre-cured lens properties and hence the final solid lens optical performance. UV light is employed to cure the liquid lens when its surface profile and focal spot are desirable. Therefore, aspherical lens with better optical imaging and focusing ability can be fabricated. Experiment results show that the surface profiles and focal spots of liquid lens varying with the increase of the electrostatic force. Near-cone shaped surface profile with smaller and more circular focal spot are achieved in strong electrostatic field. Fine aspherical surface profiles and focal spots of the liquid lens demonstrate the feasibility of fabricating aspherical micro-lens by using this method.