The proposed grating moving light modulator is based on micro-electromechanical system, the diffraction grating is provided by the deformed part on its surface, movable grating, and the two working states, on and off, are realized by controlling the displacement of movable grating. Detailed theoretical analysis and simulation for the optical properties of grating moving light modulator at working state are carried out, and the effects of duty ratio, length, frame length perpendicular to the grating period direction, grating stake width and period number of the movable grating on the working performance of grating moving light modulator are discussed with emphasis. The result shows that, the modulator is off when the distance between the movable grating and the mirror is half of the wavelength of incident light, and when the above distance is shortened to a quarter of the wavelength, the modulator is on. For the optimal contrast, it requires that, the stake width is half of the grating period and the length of the movable grating is integral times of the grating period. When the latter condition is not fulfilled, a high contrast can be obtained with short frame, narrow stake and large period number.

Based on the two-dimensional coupled-wave theory, the wave-front conversion by local volume holographic grating between cylindrical and plane waves in 90° recording geometry is investigated. The analytical integral solutions for the amplitude the transmissive and diffractive waves are presented. Furthermore, the dependences of grating diffraction efficiency on the geometric size of the grating and the focal length of the holographic lens are discussed. It is shown that, with the increase of the horizontal direction size of the grating, the diffraction efficiency of holographic grating increases. But with the increase of the size of the grating in the vertical direction, the diffraction efficiency of holographic grating decreases. The diffraction efficiency increases with the rise of the focal length of holographic lens. Furthermore the Bragg selectivity of the grating is studied, and excellent angle selectivity is proved. It is suggested that for the diffraction efficiency optimization of the holographic grating recorded by plane and cylindrical waves the recording cylindrical wave and the geometrical dimension of the grating should be carefully designed according to the request.

A novel fiber Bragg grating (FBG) sensor system based on virtual instrument (VI) and tunable laser technology is proposed. The fiber wavelength sweep is made for Bragg grating sensor array by the tunable laser source and thus the quasi-static monitoring for multiple FBG sensors is realized. The system also combines dither technique and a feedback loop arrangement, produces a zero crossing at each of the FBG central wavelength and provides improved resolution in determining the Bragg wavelength shifts. The system can also operate in dynamic tracking mode to realize the dynamic demodulation of a single sensor. The data acquisition device introduces the VI technique and simultaneous multiple-channel input and output make the system perform the function of real-time monitoring. Four-element FBG sensors are adopted in the experiment and demodulation resolutions of less than 1 με and 3.3 nε/Hz at 10 Hz for static scanning mode and dynamic tracking mode respectively, are demonstated.

A novel flow velocity sensor based on fiber grating by using the fiber grating pressure sensing setup and Venturi tube is designed. The expression of relationship between the flow velocity and the shift of central wavelength of fiber grating is derived and the experimental results are in good agreement with theoretical analysis. The central wavelength of fiber grating shifts to the shorter wavelength with rise of the flow velocity, while the bandwidth is almost unchanged. The sensor is very sensible to the flow velocity, and very stable. The measuring range is 51.0～148.2 mm/s and in that range the sensor can distinguish the change of the flow velocity as low as 0.3 mm/s which is the lowest to our knowledge. By optimizing the parameters of the sensor, the sensitivity can be improved and it can measure the velocity of different ranges.

From the point of view of optic system limitation of fiber optic gyro, the phenomena of polarization interference which suffered from the fusion error of polarization maintaining fiber and unperfect optical element is studied. Also the effect of polarization interference on transmission spectra of light source and consequently on performance of the fiber optic gyro is discussed theoretically and experimentally. Under present technical condition, it is showed that the polarization interference does not affect the scale factor of fiber optic gyro. Although the polarization interference does not change the general coherent length of light source, it affects the interference characteristic of light source that there appear more than one fringes on the interference pattern. The additional interference fringes will shorten the short coherent length of wide band light source and benefit the fiber optic gyro. So it is improper not to describe the coherent characteristic of light source just by its coherent length.

A new blind digital watermarking algorithm based on optical Fresnel diffraction is proposed. The watermarking image is transformed into a complex matrix after discrete Fresnel diffraction. The complex matrix is separated into real and imaginary parts, which are embedded into the host image for different positions, respectively. The blind watermark is obtained by replacing the value of the embedded pixel of the original host image with the average of adjacent pixels. Numerical calculation shows that the algorithm is robust to the attack of the pixel modifications, such as brightness, contrast and gray curve, and has the resistance to the JPEG lossy compressing, cropping and superposing noise. It's also robust to the resampling attack and can be drawed from the image by the screen copy. Because the watermark can be embedded in the image flexibly, the double keys are designed in the large degrees of freedom, and the watermark can be retrieved from the published image without the original image, the algorithm has high security and practical value.

Video moving object tracking technology gradually becomes the study issue and gets wide applications in the military and civil fields etc. To extract video moving objects accurately and rapidly from the real scene, a novel method for auto-extraction is proposed. First, the adaptive threshold is used to get difference image between two adjacent filtered frames. And then, to reduce the influence of noise, the connected components of the binary image are labeled to determine the region of the moving object, and by comparing it with the spatial information by edge detection, the moving object model is initialized. Finally, the image is devided into several regions. The outer pixels of the model boundary are connected respectively and the close contours is finished. Then with the closed contours, the moving object is extracted. The experimental results show that the proposed algorithm can extract the single moving target with different speed and automatically as well as moving multi-targets.

A phase unwrapping algorithm with generalized fringe pattern sequence is proposed for absolute phase measurement and phase reconstruction of three-dimensional digital object surfaces with complex topography. Firstly, various phase reconstruction techniques based on temporal phase unwrapping are reviewed and the problems existing in these techniques are pointed out. On the basis of such analysis, the detailed comparison between the fringe sequence algorithm based on positive exponent and the algorithm proposed is made in terms of the noise immunity and computational complexity. It is shown that the proposed approach has better performance. In particular, the fringe sequence algorithm based on positive exponent shows severe noise in the case that the ratio of number of fringes of successive patterns does not equal to 2, whereas the proposed approach is able to work well as usual. Furthermore, the proposed approach can determine the number of projection desired fringes according to practical situation, leading to less encoded fringe patterns required for phase unrapping and decreased processing time. The theoretical analysis and experimental results show the validity of the proposed algorithm.

A standard plane with large area and a precision moving stage are required to calibrate the parameters for the phase measurement profilometry (PMP) system in large view field. It does not suite on-line calibration because of the discommodity to tote the required plane and stage. A new method for on-line calibrating the parameters of PMP system accurately is introduced to solve this problem. An undersize calibrating plane is placed at several positions in available measurement volume randomly to acquire dense data points. The inner and external parameters of camera are estimated with the method used in photogrammetry. A global reference plane and several assistant planes are appointed. And then, the differences of height and phase in every tested position between the plane and their corresponding reference plane are calculated in division. Finally, the parameters of phase-height mapping are estimated with maximum likelihood estimate. In experiment the standard diviation of plane height measurement reaches 0.0433 mm. This method is suitable for calibrating the PMP system with large view field because only a small standard plane is required , the calibrating procedure is convenient and the result is highly accurate.

There are noticeable errors at the border of the pattern when the traditional Fourier transform method (FTM) is used to evaluate the carrier intefergram fringe pattern. A new extrapolation of fringe prolongation method for interferogram fringe pattern analysis based on FTM is proposed to eliminate boundary effects. This extrapolation algorithm is derived mathematically. And numerical simulations are performed to evaluate the performance of the method for one-dimensional digital signal and two-dimensional spatial carrier fringe pattern. The source of error is analyzed, and a comprehensive comparison is made between results from traditional FTM and this new extrapolation. The results show, the rather large error caused by the boundary effect in the course of carrier interferogram fringe pattern treatment with traditional FTM, is reduced effectively. In the wave surface measurement based on spatial phase modulation, the calculating precision for phase reaches 3.3 mrad by treating the spatial carrier fringe pattern with the new method.

The techniques of channel separation, range gate, variable gain of photomultiplier tube and cross polarization are analyzed and combined to improve the dynamic range compression of the laser echo signal in airborne laser bathymetry. The corresponding device with variable gain is developed, and implemented in experiments in tank and sea in situ. Results show that the combined technique compresses the dynamic range of submarine signal effectively and meets the demand of shallow sea dynamic range for the airborne laser bathymetry. The technique of cross polarization does not improve the effect of measuring signal compression remarkably, and the influence of after pulse effect of photomultiplier tube on depth measurement is also reported. Valuable reference for further study on dynamic range compression is presented.

A new texture-based change detection approach is presented that involves texture segmentation to describe the influence of different types of the surficial congiguration. Two images of the same position but different time are concerned. The former image, the reference image is divided into a series of textures standing for different surficial configurations, and its is assumed that the gray value of the above textures is modeled as Gaussian distributions. Through comparing the latter image, the test image, with the former, the pixel point that deviates significantly from the distribution of the texture is the singular changing point. The algorithm analyzes the statistic property of the pixel value over segmented textures, not sliding windows, so it can detect changes of any size or shape. Experiments are carried out to prove the validity of the new approach.

Tapered and lensed fiber(TLF) is the key device to couple optical energy from optical fiber into planar lightwave circuits(PLC) high-efficiently. To understand and grasp TLF's focusing performance is pivotal for PLC pigtail packaging technology. The theoretical analysis model of output beam spot diameter and far-field divergence angle, which are principal parameters to represent TLF's focusing characteristics, is put forward. The error of the model falls within 1.14%. Lightwave propagation and mode field evolution are simulated by finite-difference beam propagation method so that the spot diameter is ascertained. TLF's taper length , half core taper angle, and lens curvature radius are optimized to be 300 μm, 0.733°, 13.485 μm respectively. The focusing beam spot is observed by digital video camera experimental setup and calculated using an inverse deducing method from physical optics. The theoretical and measurement results are consistent. For a specific TLF sample, the spot diameter value by inverse deducing method is differed from the theoretical one with error of 3.15%, and the error for far-field divergence angle is 3.67%.

The experimental results of a 2×2 integrated thermooptic Mach-Zehnder interferometer (MZI) switch based on multimode interference (MMI) couplers are reported. The insertion loss is 3.40 dB, polarization-dependent loss is 0.47 dB, extinction ratios at bar state and cross state are 32.01 dB and 16.42 dB respectively, response time is less than 3 ms, and power consumption is 658 mW. Regarding to asymmetry of extinction ratios at bar state and cross state, theoretical analysis is presented. Coupling ratio of the two multimode interference couplers deviates from 50:50, but the deviation is nearly the same, which is decided by good uniformity of semiconductor planar lightwave circuit (PLC) process. This property affects extinction ratios at bar state and cross state in different mechanisms. Adding metal heating electrode on waveguide affects its effective index and analysis based on experimental results is given. The increment of waveguide effective index is in the order of 2×10-4.

A novel optimization algorithm along with the mathematical model for dose control parameters in a step and scan lithography, aiming at an optimal match of the throughput, dose accuracy and cost of ownership of deep ultraviolet (DUV) excimer laser simultaneously is proposed. With the help of variable laser repetition frequency and introduction of a new concept called effective number of pulses, the optimization strategy for a given dose in the effective dose range is achieved and the detailed method to calculate values of all the dose control parameters is proposed. The theoretical study and numerical simulation demonstrate that the new algorithm not only maintains the advantages in throughput and dose accuracy of the currently used one, but also overcomes its drawback of not considering the reduction of laser cost of ownership. It is fully expected that the novel algorithm will show its superiority and provide a better application with the further improvement of DUV excimer laser and its dose control technology.

Many high-power lasers typically suffer from reduced beam quality due to thermally induced aberrations. Adaptive optics is an effective way to compensate the dynamic aberration. As a key component of adaptive optics system, a novel deformable mirror with 30 mm×30 mm effective reflecting surface and 49 electrostatic actuators has been fabricated successfully for wavefront correction of high average power lasers. The characteristics of this deformable mirror is analyzed and simulated in detail and the simulation result agrees well with the measured result. To meet the requirement of closed loop control, the optical influence function matrix is measured thoroughly. Based on the matrix, the laser wavefront aberration is corrected. From the result, it is explicit that the thermally induced aberration of high-power lasers is compensated by the deformable micro-mirror.

The electronic structures and optical linear response functions of ZnO are calculated, the relationships between electronic structures and optical properties are investigated by using first-principles ultra-soft pseudo-potential approach of the plane wave based upon the density functional theory. The dielectric functions, reflection spectra, refractive index and extinction coefficient of ZnO dominated by electron inter-band transitions are analyzed in terms of the precisely calculated band structure and density of state. The theoretical results agree well with the experimental value, offering theoretical data for the design and application of optoelectronic materials of ZnO. Meanwhile, the calculated results also enable more precise monitoring and controlling during the growth of ZnO material.

A new azo-dye sy03 is introduced as photoalignment material of twist nematic liquid crystal (TN-LCD). sy03 is added into the mixture composed of polyimide SE-3310 and N,N-dimethylformamide for photoalingment of 90° TN-LCD. And the electro-optic perfermance of the cell aligned by it is measured, and then compared with that of the cell photoaligned with PI SE-3310 only. Apparently, the former is better than the latter for shorter raction time and lower threshold voltage with 98 ms reaction time and 1.7 V threshold voltage. Stability and contrast are improved, and the electrooptic response curve is sharper. After the cell is heated to 150 ℃, obvious change for its electro-optic performance does not occur, which proves its favorable thermal stability. By measuring the polarized UV absorption spectra, it is proved that the easy direction of liquid crystal director is perpendicular to the polarization direction of irradiation ultraviolet light.

The measurement of particle size distribution and refractive index of the thin layers in two-layer tissue phantoms by using the diffuse backscattering light dependent on the azimuth angle of the linearly polarized incident light. In the two-layer model, the upper layer consists of polystyrene pheres suspension or HeLa cells, and the bottom layer is intralipid solution. Optical properties of both layers are supposed to match those of biological tissue. Based on Mie theory, the theoretical model for dependence of particle morphological parameters related polarized diffuse backscattering light intensity on the polarization angle of the incident light is built up. The particle size distribution and relative refractive index are derived by using inverse program of floating genetic algorithm. Comparison of theoretical and experimental results are made, and it is found that the morphological structure information of thin layer tissue can be drawn by measuring and analyzing the polarized differential signal of the azimuth angle-dependent diffuse backscattering light.

Spatially resolved reflection close to light source has drawn great attention in the fied of medical optics and photonics recently. This research is considered to develop a new noninvasive technique of measuring the optical properties of intravital biological tissue. It is limited to study the spatially resolved diffuse reflection of tissue close to light source with diffusion approximation. The radiance distribution close to light source can be analyzed by P3 approximation theory considering the third-order moment of phase function. The spatially resolved diffuse reflection based on P3 approximation is studied. The equation set of the P3 approximation and its Green function approximate solution are derived from the PN equation set of the transport theory. The relationship between P1 approximation and the diffusion approximation is demonstrated, and a complete solution of P3 approximation with the extrapolated boundary conditions and collimated beam approximation is obtained. The effects of the second-order parameter on the P3 approximation diffuse reflection are studied, and the results are compared with them of diffusion approximation and Monte Carlo simulation. The application range of P3 approximation is presented.

To set up the evaluation base and method of medical rigid endoscope distortion, by using optical axis symmetrical spherical Z view field as the model to simulate concave characteristics of body cavity, the analysis base of endoscope object-image conjugation is established. By using optical principle together with the definition principle in ISO 9039:1994 “Optics and optical instruments——Quality evaluation of optical systems——Determination of distortion”, with definition of distortion determined by clinical requirement of theoretical distortion, the distortion conversion formula of different sphere Z shapes is deduced by main ray trace principle. The medical rigid endoscope distortion definition and expression which are expressed as unit relative distortion, and distortion conversion formula and testing method of conversion of view field surface, are all established. The distortion evaluation base and method established are applicable for the medical rigid endoscope standard.

KBA microscope is a type of non-symmetrical and non-coaxial grazing incidence imaging system. Its configuration is complex, the adjustment precision is high, so that in practical experiment the imaging performance of KBA microscope is not easy to master. Imaging simulation by using optical design saftwave ZEMAX is made to provide valuable reference for adjustment and imaging analysis. The imaging process of KBA microscope for point source is simulated by using ZEMAX. The depth of focus and depth of field of KBA microscope are about 1 mm and 50 mm respectively. The grazing angle affects the imaging greatly according to the simulation. The upper limit of the spatial resolution of KBA microscope is 3 μm for the detector whose pixel is about 10 μm by simulation. The clear X-ray image of KBA microscope is obtained for the grid target whose period is 20 μm based on XINGGUANG Ⅱ facility, which establishes the base for advanced study of developing grazing imaging system.

Surface plasmon resonance (SPR) is a phenomenon induced by the polarizing energy coupling and resonant exciting of surface plasmon wave and incident TM light wave. The SPR on gold film is studied with combination of scanning near-field optical microscope (SNOM) and SPR technique. A novel Kretschmann type of SPR coupling device with special structure is designed and set up, and the fabrication method of surface plasmon with thickness gradient is presented. Based on the above preparation, the curve of SPR is measured with varied incident angle conditions, and the angle sensitivity for SPR is 1°. The image of gold film surface is obtained with SNOM under PSR conditions, and it is found that the image is clearer under SPR condition than that without SPR and more details are distinguished. The performances, such as signal-noise ratio and resolution, for SNOM are greatly improved with the SPR technique.

By sensitizing with 514 nm green light, 488 nm blue light and 390 nm ultraviolet light respectively, recording with 633 nm red light, the effect of wavelength of sensitizing light on holographic storage properties of oxidized (Fe,Ni):LiNbO3 crystal is investigated in detail. It is shown that by shortening the wavelength of sensitizing light gradually, nonvolatile holographic recording properties of oxidized (Fe,Ni):LiNbO3 crystal is optimized gradually, and 390 nm ultraviolet light is found to be the best among the three kinds of sensitizing light. Considering the absorption of sensitizing light, appropriate sensitizing light wavelength should be adopted to obtain the best performance in two-center holographic recording. On one hand the sensitizing light with short wavelength can sensitize the deep center effectively, on the other hand the absorption is too strong, for example the substrate absorption which is useless for photorefraction, to allow valid sensitization in the thickness direction. So in practice a trade-off is always needed. Explanation is also presented theoretically.

LiNbO3:Ru crystals have been grown by Czochralski method, then oxidized in O2 for 20 h. Dependence of recording characteristics of grating on recording wavelength, as well as effect of oxidation treatment on transmission spectra and recording characteristics, has been investigated in LiNbO3:Ru crystal. The results show that the optimal recording wavelength is 458 nm; oxidation treatment increases the absorption of crystals, and also increases the recording sensitivity and saturated diffraction efficiency, which is different from the dependence on oxidation state in LiNbO3:Fe crystals. The abnormal oxidation state dependent characteristics may be induced by that the dark attenuation mechanison of electron tunneling is present, and Ru is in more than two valence states.

Based on the beam coherent-polarization matrix approach and propagation law of partially coherent beams, the propagation properties of partially polarized Gaussian Schell-model beams diffracted through an aperture in the far field are studied. Detailed numerical calculation results and physical analysis are presented and illustrated for the far-field polarization and intensity properties. It is shown that the far-field behavior of diffracted partially polarized Gaussian Schell-model beams depends on the truncation parameter, spatial coherence parameters and diffraction angle. The corresponding results for the unapertured case are given and a comparison with the previous results is also made.

A phase-locking fiber laser array with up to 60 W of coherent output power based on two large-core fiber is reported. The slope efficiency of the in-phase mode is 37%. For the two core space cases, the steady high-contrast interference strips are observed. When the whole system operates under high pump power level, no thermal effects for the spatial filter have been observed, which means that we can increase the coherent output power further by increasing the individual fiber laser power.

Monascus pigment fades in sun light, and ultraviolet radiation(UV) is main reason causing photobleaching of organic compound. To study the mechanism of photobleaching for monascus pigments, a monascus red pigment (resolved in water, molecular formula C19H28N2O5) is radiated with UV-light until colorless, the molecular formula of the colorlessness is determined as C14H9NO6 by infrared spectrometry, mass spectrometry and hydrogen nuclear magnetic resonance. The photobleaching mechanism of the red pigment is deduced according to photochemical theory: firstly, the acyclic side-chain in monascus pigment is cut at α-carbon according to Norrish Ⅰ mode, radicals are formed, and then same reaction happens at 7-carbon methyl; electron-transferring, double-bond conversion and addition reaction between double-bond and hydroxyl radical, superoxide radical from water occurrs, and conjugated double-bond disappeares, which causes bleaching of monascus pigments. In order to avoid bleaching of monascus pigments, stabilization of acyclic side-chain should be considered primarily, and addition of radical clearing reagents in pigments is also prefered.

Using a distributed feed back (DFB) tunable diode laser as the injection light source, absorption spectrum around 1.573 μm with high signal-to-noise ratio (SNR) and sensitivity is obtained by using off-axis integrated cavity output spectroscopy and scanning the laser and cavity simultaneously. The typical sensitivity is 4×10-8 cm-1 (SNR=2,1s integrated time). It is not valid to fit the integrated cavity output spectrum with the nonlinear least square method, and it will make the self-broadening coefficient broadened as about 2.39 times of the real value. The air-broaden coefficient approaches to the real one. Absorption coefficient fit is necessary to obtain the correct parametersof spectral line width. Theoretical analysis and experiment demonstration prove the conclusion.

Composite films with nanoscale Au particles uniformly embedded in BaTiO3 matrices (Au-BaTiO3) were prepared by using pulsed laser deposition (PLD) technique. High-resolution transmission electron microscope (TEM) and X-ray photoelectron spectroscope (XPS) were used to characterize the films. It could be seen from the TEM micrographs that the film exhibited a very homogeneous distribution of spherical Au particles. The diameter of the Au particles was estimated to be 2～3 nm. The X-ray photoelectron core-level spectra of Ba3d, Ti2p and Au4f lines were presented and suggested the films were composed of metal Au embedded BaTiO3 matrix. The optical absorption of the films was measured in the wavelength range of 330～800 nm, and the absorption peak due to the surface plasmon resonance of Au particles was found around 500 nm. The third-order optical nonlinearity of the composite films was investigated by the Z-scan method using a Q-switched Nd:YAG laser with a wavelength of 532 nm and a pulse width of 10 ns. The nonlinear refractive index n2 and the nonlinear absorption coefficient β were determined to be -2.42×10-6 esu and 2.22×10-6 m/W, which showed that the Au-BaTiO3 thin films had a large nonlinear optical susceptibility.

The effect of δ-doping in n-type layers on crystal performance of GaN epitaxial films on Si substrates was studied by ω-scan of different crystal planes with X-ray diffraction method. The full width at half maximum (FWHM) values of the serial crystal planes of the GaN epitaxial films on Si substrates were reported. By using the lattice-rotation model, the screw and edge dislocation densities of the samples were calculated. The results showed that the screw dislocation density increased, the edge dislocation density decreased, and the total dislocation density decreased in the δ-doped GaN films. By comparing the relevant FWHM values of ω-2θ scan of δ-doped and untreated samples, it was found that the inhomogeneous strain of GaN films increased by δ-doping. In addition, LED fabricated using the δ-doped samples showed better electroluminescence performance and I-V characteristic compared with that of the untreated samples.

For the evaluation of lightness threshold characteristics of the visual color matching the experiment is carried out. By using cathode-ray tube (CRT)-generated color stimuli under five different gray backgrounds, the visual color matching is achieved for 19 neutral standard stimuli with their lightness L* ranging from 5 to 95 by the step of 5 CIELAB unit. Upon the data processing and the analysis of the experimental results, the crispening effect and the Weber's law, which are about the correlation between the visual lightness discrimination threshold of color stimuli and the lightness of the background, are validated. Furthermore the visual color matching data from the present experiment are used to evaluate the CIELAB-based related aberration formulae. For the lightness-difference predicting, the CIEDE2000 outperforms the others, followed by CMC, and with CIE94 and CIELAB the poorest.