By means of the Mie scattering theory, the absorption efficiency factor and other optical factors of hygroscopic aerosol made of NaCl and H2O as well as (NH4)2SO4 and H2O which are set as the typical example are calculated, and the equivalent absorption coefficients with time of them are analyzed. The influence on the equivalent absorption coefficient when ignoring the energy absorbed by particles themselves is analyzed and the relative error of the equivalent absorption coefficient considering and ignoring the energy absorbed by the particles themselves is 234.7% and 255.2% at the time 1 μs, and the influence of different relative humidities and wavelengths on it is discussed. The relative errors of the results calculated by an uniformly mixed model are discussed, and the relative errors of the real results and calculated results are maximum at the time 1 μs which are less than 3.62% and 7.07%, respectively.

Telescope guiding error caused by atmospheric turbulence is discussed, which affects significantly the accuracy of telescope auto-guiding system. Guiding precision of a single point source target is limited by the atmospheric coherent length and coherent time, and several point source targets and extended celestial bodies guiding precision also have relation to the turbulence height. Furthermore, analysis and simulation (numerical simulation) results show that modern astronomical observations must consider the influence of atmospheric turbulence on the accuracy of the auto-guiding system. Extending the exposure time can reduce the influence of the turbulent atmosphere, but also reduce the feedback control frequency of the auto-guiding system. The guiding beacon of several stars or extended source can reduce partly auto-guiding error caused by high-layer atmospheric turbulence, which can appropriately reduce the exposure time of the auto-guiding system, and improve its feedback control frequency.

The solar radiation pressure on water cloud particles is analyzed with Mie scattering theory and the two stream radiative transfer method. It is found that this pressure can generally be some percents of the gravity on the particle whose radius is less than 10 μm, and that for a particle with radius about 0.3 μm, the pressure reaches the maximum and can be some tens percents of the gravity. Therefore the solar radiation pressure must be taken into consideration in the studies in cloud physics.

Modulation transfer function (MTF) velocity mismatch feature for time delay integration (TDI) complementary metal-oxide-semicoductor (CMOS) area image sensors is studied. A model of MTF velocity mismatch is proposed. The effecting factors such as accumulation stage, pixel size, lens magnification, line cycle, motor velocity are analyzed. A TDI algorithm for CMOS area image sensor is applied to achieve time delay integration. The TDI-CMOS system is developed based on a FPGA development board. The experimental results show that fMTF increases 50% by 8 accumulation stage compared to CMOS area sensor, when the intensity is 3 lx and velocity mismatch M(ΔV/V) is less than 2. The fMTF at the Nyquist frequency decreases 10% by 8 accumulation stage, when the velocity mismatch M(ΔV/V)=2. When the velocity mismatch M(ΔV/V)=10, the fMTF decreases 35%.

The minitype flat-field holographic concave grating spectrograph equipped with CCD detectors are widely used for spectral analysis. They are accepted for some remarkable advantages, such as compact structure and rapid and efficient testing process. However, restricted by imaging distance of the spectrometer, it is difficult to improve the spectral resolution greatly just by optimization of the holographic concave grating. A design method of double-grating minitype flat-field holographic concave grating spectrograph is proposed. The single grating in conventional spectrograph is replaced by two gratings which are equipped with the same geometry. A double grating flat-field spectrograph with a wavelength range from 400 nm to 1000 nm is designed. The calculation results show that the resolution of the newly designed spectrograph can be almost two and a half times as great as the conventional spectrograph. The light throughput efficiency can also be greatly improved, which is demonstrated by analyzing diffraction efficiency of the grating. The double-grating minitype flat-field holographic concave grating spectrograph is developed and adjusted. The experimental results agree with the theoretical calculations very well.

The preparation and characteristics of holographic electrically controlled grating with high diffraction efficiency based on nano-Ag-doped polymer dispersed liquid crystal (PDLC) materials are reported. By adding appropriate amount of nano-Ag material to the original PDLC materials system to make the holographic volume grating, the influences of doping mass ratio of nano-Ag to the diffraction efficiency, driving voltage and response time of holograhic polymor dispersed liquid crystal (H-PDLC) grating are researched. The experimental results indicate that, through doping nano-Ag particles, the separation of polymer and liquid crystal is optimized and the separation between polymer and liquid crystal becomes exhaustive; the primary diffraction efficiency of the H-PDLC grating is obviously improved, and the electro-optical property is ameliorated simultaneously. Preliminary analysis indicates that the improvement of the characteristics is attributed to the surface plasmon effect of nano-Ag and the matching of the refractive index system.

Long-period fiber grating (LPFG) has a wide range of potential applications. But it is necessary to solve the cross sensitive problems of different physical quantities effectively before its practical application. Based on the sensibility of LPFG to the thickness and refractive index of cladding material, a new-type LPFG sensor composed of two-section multilayer transversely distributed refractive index is proposed. The influences of refractive index, thickness and length of the coating layer on the spectral characteristics of the new-type LPFG are analyzed by using coupling mode theory and transfer matrix method. The simulation results show that the resonant band splits due to the particularity of the LPFG structure. It can be concluded that this LPFG design can solve the cross sensitive problem and then can realize synchronous measurement of temperature, strain and other physical quantities.

A novel optoelectronic oscillator with multiple long fiber loops is proposed. This oscillator can simultaneously have lower phase noise and higher side mode suppression ratio than current multiloop optoelectronic oscillators. A three-fiber-loop oscillator with more than 4 km fiber length is investigated in theory and experiment. The optoelectronic oscillator with frequency of 10 GHz, phase noise of -130 dBc/Hz at 10 kHz offset, and side mode suppression ratio of 60 dBc is demonstrated. The agreement of experimental results and theoretcal analysis justifies this method.

An optical preamplifier is utilized to improve the signal-to-noise and distortion ratio RSNDR of inter-satellite microwave photonics links considering the large signal losses in distant propagation and serious deterioration caused by inter-modulation distortion. An optically preamplified inter-satellite microwave photonics links model with two radio-frequency (RF) signals input is established and an analytical expression of RSNDR is derived. The direct current (DC) bias phase shift of modulator can be optimized so as to maximize the RSNDR given the desired input RF signal power, and the effects of the optical preamplifier parameters on the optimum DC bias phase shift and RSNDR are also examined. Simulation results show that the most limitative factors degrading the RSNDR are changed, and the fundamental power is seen to increase more compared with the power of third-order intermodulation (IM3) plus noise due to optical preamplifier. Thus, RSNDR can be improved with respect to the case of non-optical preamplifier. For the preamplifier gain of 20 dB and noise figure of 3 dB, an improvement of about 24 dB in optimum RSNDR is accessible. The optimum DC bias phase shift is found to be insensitive to the preamplifier gain and noise figure while the optimum RSNDR is sensitive to the preamplifier gain and noise figure.

The photo-thermo-refractive (PTR) volume grating is formed by PTR effect in photo-sensitive glass. PTR volume holographic grating has unique advantages for the applications of laser technologies owing to its excellent wavelength and angular selectivity, high diffraction efficiency, high thermal stability and high damage threshold. The diffractive characteristics and stability of the photo-thermo-refractive volume grating are investigated. A transmission hologram is recorded under 325 nm laser exposure in the PTR glass. According to the principle of variable wavelength readout, experimental setup is designed for readout of transmission photo-thermo-refractive volume grating. The angular selectivity and the stability under laser irradiation of the transmission PTR volume grating after thermal development are measured experimentally. The photo-saturation effect is observed and a characteristic time constant is acquired through by fitting the calculation and experimental results to describe the stability.

In the optical readout infrared thermal imaging system, the initial reflector deformation of the focal plane array (FPA) decreases the optical detection sensitivity for the system greatly. According to the design and fabrication of the FPA, two optimized design schemes for reducing the initial deformation of the FPA reflector are put forward: thinning the Au layer on the reflector and fabricating reflector with stiffeners. Based on the theoretical analysis, a FPA with a unit size of 200 μm is fabricated and the Au layer of its reflector is thinned. Its reflector curvature radius and the optical detection sensitivity for the system are respectively increased to 4.71 times and 5.2 times of the FPA without thinning process. And a FPA with a unit size of 60 μm is fabricated, its reflector is with stiffeners. Its reflector curvature radius and the optical detection sensitivity for the system are respectively increased to 4.29 times and 1.18 times of that of the FPA without stiffeners. The experiments verified the result of theoretical analysis.

With optical micro scanning technology, the spatial resolution of micro thermal imaging systems can be improved without changing the detector structure. But in order to obtain high-quality oversampled reconstructed image, the micro scanning position must be calibrated. A each point adaptive calibration micro scanning method based on the zero calibration theory is proposed. The reconstruction contrast experiments of undersampled microscopic thermal images are done before and after calibration with the thermal image and the real thermal microscopic image. The experimental results show that the method significantly improves the oversampled reconstructed image quality, and enhances the system spatial resolution. This method can also be used in other electro-optical imaging systems.

A wave-front aberration measurement method of lithographic projection lens based on adaptive aerial image denoising is proposed. Principal component analysis (PCA) and multivariate linear regression analysis are used for model generation. Weighted least-square (WLSQ) method based PCA is used to get the principal component coefficients that are used for extracting the actual Zernike coefficients. Both the noise model of aerial images and the standard deviation model of noises are obtained by statistical analysis of actually measured aerial images. The standard deviation of the noise is used as weighting factors of the weighted least-square method. Accurate principal component coefficients and Zernike coefficients can be calculated because of the adaptive and lossless denoising ability of this method. Compared with wave-front aberration measurement techniques based on principal component analysis of aerial images (AMAI-PCA), the new method can provide more accurate results. Simulations show that AMAI-WLSQ can enhance the accuracy by more than 30% when the range of wavefront aberration is within 0.1λ. Experiments also show that AMAI-WLSQ can detect aberration shifts more accurately.

Based on the compressed sensing (CS) theory, an imaging process for three-dimensional (3D) objects is illustrated. In order to solve the problem that the calculation of the 3D imaging based on CS is too large, a simple method of 3D information calculation is proposed, by which only two CS processes are needed to obtain 3D information of objects located at several distances, thus reducing computation greatly. Then, the 3D imaging process is simulated to illustrate the effect of sampling rate on the precision of distance calculations. A real 3D imaging system is built, which shows that this method is workable.

Since there exist vibration and orientation errors, a phase shifter usually suffers from both random translational error and tilt-shift error during phase shifting in an interferometer, and it will influence the accuracy of measurement result. So the environmental stability and the performance of phase shifter are subject to rigorous requirements in high accuracy measurement. To reduce these requirements, focusing on the problem that the nonuniformity of the background intensity and modulation will affect the calculation of phase-shift plane in random and tilt phase shifting interferograms, the acquired interferograms are normalized, and phase distribution is determined with least-squares-based iterative algorithm. During iteration, the interferograms are divided into small blocks to calculate local phase shifts, and then these phase shifts are fitted to a phase-shift plane. Results of computer simulation indicate that the proposed method can eliminate the coupling effect of background intensity and modulation on the calculation of the tilt coefficients, so it can compensate tilt phase shift errors during phase shifting. Compared with other methods, the proposed method has faster convergence as well as higher accuracy. Experimental results further demonstrate the validity of this method.

The aspherical reflector surface is tested based on basic phase measuring deflectometry, and the mid-high frequency error of result is studied. The intensity-modulated patterns are displayed on the thin film transistor screens. The camera observes and records the fringe pattern reflected by the tested reflector. The phase distribution is obtained by the phase-shifting and phase unwrapping technique. The surface normal is obtained through ray trace, the surface profile gradient distribution is obtained according to reflection law. And the surface is reconstructed by numerical integration. The mid-high frequency error is studied by the Zernike polynomial fitting.

Based on the use frequency of Chinese characters and its space frequency spectrum analysis, a Chinese characters testing chart is designed for digital camera image-quality evaluation. Under statistical analysis of test results of spatial frequency response (SFR), subjective quality factor (SQF) and the Chinese characters testing chart for 37 different models of digital cameras, the empirical formulas between the just recognizable Chinese characters point size and SFR/SQF are obtained. Verification tests of 10 other digital cameras show that measured SFR/SQF values fall in 95% confidence interval. The Chinese characters testing chart is similar to visual testing chart. This evaluation method has some advantages compared to other methods, such as convenient operation, simplified equipment.

The wavelength tuning interferometer is applied to measure large optical components. In order to obtain the wavefront using the algorithms with certain phase steps, the steps should be calibrated. When it is measured at long interference cavity length, the calculating precision of algorithms with certain steps is low. It is mostly because of the limited resolution of the laser controller. Based on analyzing the relationship between the interference cavity length and the calculating error of the wavefront, an adaptive phase selecting method is presented. Firstly, several periods of interferograms are sampled according to the voltage-phase calibration curve. Then the intensity values of the interferograms are uniformly sampled. By calculating the sampled intensity values with the randomly phase shifting algorithm, the phase steps between every two interferograms are obtained. According to the steps, four interferograms with π/2 step are chosen from those interferograms. At the end, the measured wavefront is obtained by calculating the four interferograms with four-step phase shifting formula. The experimental result shows the validity of the presented method. It can obtain the wavefront when it is measured at long interference cavity length in the wavelength tuning interferometer. And after comparing with the result of no selection method, it is clear to see that the presented method is of high precision.

Share-beam multi-channel laser ranging sensor is usually used to detect rut depth by measuring several discrete points of the road which are used to form section information. The great transverse sampling distance causes large measurement error. A new laser method to detect rut depth is introduced; it measures three-dimensional (3D) section by integrating line laser sensor with 3D camera, which is used to resolve rut depth. 3D camera collects light image in the form of line structure projected on the road by laser at a certain angle, obtains 3D section data and rejects the abnormal value by the Pauta criterion. After rotating, translating and pattern recognition, left and right wheels mark and maximum rut depth are achieved. A case study shows that repeatability and correlation of data are over 98%. Compared with traditional methods, the proposed method has the better performance of short sampling distance, high accuracy, low cost, versatility and widely promotional value.

A measurement technique for the Mueller matrix based on a single photo-elastic modulator is proposed to improve the current measurement methods. An optimization algorithm and a two-step procedure of system parameter calibration are also presented. System parameters are calibrated by the two-step calibration procedure. Then, the Mueller matrix of the measured sample is obtained with the optimization algorithm. The experimental results show that the retardation and the fast axis angle of the measured quarter-wave plate are 90.4185° and 0.2348°, respectively. The corresponding errors are less than the retardation tolerance λ/300 and the maximum rotation error 0.4°, respectively. Compared to the standard Mueller matrix of a quarter-wave plate whose fast axis angle is set at 0°, the maximum relative errors of each element of the Mueller matrix of the measured quarter-wave plate are 1.97% and 0.83% with direct and indirect measurement method, respectively. Both errors are less than 2.11%, which is the simulation value of the maximum relative error. Decreasing the retardation tolerance or improving the precision of the rotation stage can diminish the maximum relative error of each element of the Mueller matrix.

A measurement system is established for the parabolic trough unit mirror in concentrating solar power (CSP). The system applies the fringe reflection technique and the temporal phase unwrapping technique. Based on three-dimensional profilometry system model, the measurement system has less equipments and simpler operation. Without any strict requirements to the system equipment, a sinusoidal fringe is projected with projector, and the images are recorded by a camera after reflected by the unit mirror. Then the surface is computed by the parameters of the system. Experimental results verify that the measurement method is reliable. The system is helpful to the measurement work, and has a very good application prospect in the solar thermal power field.

A cryogenic collimator is needed to test the modulation transfer function (MTF) of the infrared cryogenic camera. The detector of the infrared low temperature camera cannot work normally at room temperature, besides the camera, the off-axis parabolic mirror and the simulated target are spatially separated. So it is necessary to adjust the boresight direction of the camera with the collimator, meanwhile the simulated target must be set on the focal plane and at the 0′ field of the collimator. By using the interferometer, the boresight of the camera and the collimator can be individually elicited to external reference cubes a and b. Based on the direction cosine matrix of the two cubes′ coordination system, the boresight of the camera can be elicited to the direction of the boresight of the collimator. The accuracy of this method is analyzed, and the image of the experiment is also shown. The experimental result shows that the MTF of the camera meets the demand, and it also indicates that the method is reasonable and feasible.

Damage experiments are conducted by irradiating fused silica with the multiple wavelength laser near field. The multiple wavelength laser consists of 1053、 527、 351 nm laser. It designs a definition of damage threshold based on laser near-field irradiation and extracts damage areas from damage images by the marker-based watershed algorithm with gray control. The initial damage threshold is defined as the fluence of critical site between damage region and no damage region, which is calculated by comparing the damage image with the multiple wavelength laser near field. The research shows that the damage of fused silica is induced by the three wavelength lasers. The 351 nm laser plays a leading role. The initial damage threshold is 8.22 J/cm2. With multiple irradiation of fused silica in multiple wavelength laser, the damage growth of exit surface is exponential, and the coefficient of damage growth is 0.59.

The coupling between solar light radiation and laser rod medium in a solar pumped laser affects the efficiency of the laser. To optimize the pumping system, simulation of the two-stage pumping system with a Fresnel lens and a conic pumping cavity is carried out with Tracepro software. According to the power density distribution along the axis at focal place of the Fresnel lens, the diameter and position of the pumping cavity window and the distance of the window from the Fresnel lens are optimized. The power density distributions along the laser rod axis of different cavity lengths and different cavity tapers are also analyzed. The optimal structure of taper cavity is obtained. The mirror reflecting cavity and ceramic cavity are introduced in detail.

A comprehensive metal surface reflection model is introduced to demonstrate the feasibility of the differential visual measurement theory. In order to seek the factual basis, the reflection brightness of some roughness comparison specimens is measured in the plane of incidence, and then the distribution law is summarized based on a large amount of data. A vision system is built, and the images collected from the bright and dark fields are fused by differential algorithm. Experimental results show that the target surface defects are greatly enhanced and the clutter background information is effectively suppressed. The differential visual measurement system based on the reflective properties of the metal surface shows its superiority in improving contrast and enhancing edge of images.

The nano copper sulfide is prepared by ultrasonic atomization with Cu(NO3)2 and Na2S solutions of 0.5% (mole fraction) as raw materials. The pH value of the solution is adjusted to 6~8. The atomized Cu (NO3)2 is gradually added into the solution of Na2S which is strongly stirred. The nano-semiconductor copper sulfides (CuxS, 1≤x≤2) are obtained after aging and filtering. The influence of heated temperatures and ratio of raw materials on chemical composition of copper sulfide are analysed. The phase of copper sulfide and the chemical composition are investigated by X-ray powder diffraction (XRD). The morphological image of the copper sulfide is observed by scanning electron microscope (SEM). The absorptivity and transmittance of copper sulfide in state of sol from ultraviolet to near infrared wavelength are recorded. The results indicate that the copper sulfides are of high absorbance for near infrared light, which are attributed to the electronic transitions in the energy bands. They also have high transmittance for visible light. The transmittance declines slightly along with Cu2S approaching to CuS.

Light propagation in photonic band gaps in two-dimensional organic octagonal quasiperiodic photonic crystal slabs is investigated by finite-difference time-domain method. The transmission property and light localization in the polystyrene air-rod slab and air polystyrene-rod slab are compared in detail. The results show that even in extremely low-index dielectric contrast of rods, the photonic band gaps and eigenmodes are observed in the visible spectrum. Besides, the central position of bandgap is red-shifted with the increase of slab thickness. When defects are introduced into two quasiperiodic structures, the occurrence position of defect modes and property of red-shifting in wavelength of modes are different with the increase of size of defect nanocavities. The difference in property originates from the competition consequence of two physical mechanisms which are the energy levels of defects in photonic crystals and the resonance of modes in the defect cavity. The results may give theoretical support for fabricating luminescent devices based on organic quasicrystals.

Band gaps of both TE-polarized and TM-polarized modes photonic of two-dimensional triangular-lattice ellipse-lattice-points air-hole photonic crystal are caculated by finite element method. By changing the size and direction of ellipse lattice point air holes, the effects of air hole filling ratio and lattice points direction to the photonic band gaps are studied. The results show that TE-polarized mode band gaps are easier to be formed in air-hole photonic crystal. With different filling ratio, lattice point direction has different effect on both TE-polarized and TM-polarized modes band gaps. There is no complete photonic band gap no matter where lattice points orient.

A new theoretical model of an RC circuit is proposed for prediction problem of laser induced biological tissue temperature rise. The RC circuit system function and unit impulse response are deduced based on Kirchhoff′s voltage law (KVL). Then RC circuit zero state response model is deduced from the convolution of unit impulse response and rectangle input signal. The two model constant parameters are calculated from experimental results of the laser irradiated bio-tissues temperature. Two model parameter calculation methods are proposed and simulated. Theoretical calculation and experimental results show that the temperature response curves are consistent. Relative error ranges of liver and muscle tissue peak temperature are -0.0557 ℃~-0.0025 ℃ and 0.0139 ℃～0.0641 ℃ respectively, and average relative error ranges of the temperature curve are 0.55%～2.39% and 0.38%～0.99% respectively. This method needs less parameters and is more precise than classical Pennes bio-heat transfer equation model, which provides a new method for laser and bio-tissues photothermal effect research.

Far ultraviolet imaging spectrometer for upper atmosphere remote sensing is mainly used in observation on the far ultraviolet radiation and imaging for the mesoclimate phenomenon in the upper atmosphere. The foundation of correlated instruments is still frail in our country. A program in optical design is presented to improve the study of the imaging spectrometer for far ultraviolet observation in 130~180 nm. It is composed of the telescope with an off-axis parabolic mirror and the imaging spectrum system structure with tandem Wadsworth system. The tandem Wadsworth spectral imaging system adopts the collimator as an off-axis parabolic mirror. The light splitting device consists of a plane grating and a concave grating. The structure can realize quadrate dispersion. And the concave grating is used for focusing and imaging. Based on the aberration theory, the optical path function and aberration coefficients of the system are analyzed, and perfect imaging conditions of the improved structure are obtained. A design example using the perfect conditions is designed to meet the requests of the application in space observation in low orbit. The results demonstrate that the aberrations of the system are substantially corrected, and the modulation transfer functions in total fields of view and all waveband are more than 0.6. The improved structure is more convenient. The space resolution and the spectral resolution are both high.

With the analysis of incident angle and system aberration of microlens array, which would affect the illumination efficiency of the optical system, the optical efficiency and illumination uniformity are optimized. The efficiency loss which is caused by large incident angle is minimized by varying the curvature radius of the free-form double-lens. Two spherical lenses are used as Fourier integrator after the microlens array to increase the system efficiency. The simulation result shows that the optical efficiency and illumination uniformity are 60.51% and 94.24%, respectively, which proves the feasibility of the theoretical analysis.

Double Amici prism is a kind of composite prism, as the dispersion component of the imaging spectral system, avoiding some problems of the single dispersion prism. We should give out the each angle′s processing targets of the double Amici prism. Every angle error has a different effect on the dispersion. We design a coded aperture imaging spectral system. A double Amici prism is designed to meet the needs of the applications of the specific system. The mathematical model of the double Amici prism dispersion is deduced from the standpoint of ray tracing. In this particular optical system, we give out the effect of every angle of the prism on the line dispersion, then analyze of the angular error chain′s effect on the line dispersion, and finally give out the production index of the prism. The results contribute to the processing and production of the prism.

To meet the research requirements of 45 nm node or even below microlithography, the configurations and specifications of experimental lens are determined. Based on the aberration theory, several refractive elements are inserted into a non-concentric all-reflective Schwarzschild system with a small central obstruction so as to achieve smaller obstruction and hyper-numerical aperture. A Schwarzschild catadioptric lithographic lens whose numerical aperture is 1.20 is designed with a small central obstruction. Designing results show that the objective′s working bandwidth is 100 pm, viewing field of image is 50 \mm, the linear obstruction ratio is 13%, modulation transfer function is greater than 0.45 at the resolution of 80 nm (6240 lp/mm), and its distortions of all field points are below 6.5 nm. It can meet the requirement of deep ultraviolet immersion lithographic experiment with 45 nm nodes.

By the analysis of the scattering situation of the rough surface, it is found that the ordinary metal material scattering energy is centralized in 10°. Based on the scattering characteristics, the method of the outer baffle design is put forward, the baffle rings′ restraint angle is 5° larger than the stray light suppression angle which is calculated based on reflection theory, and the effect of the outer baffle to suppress the stray light is very good. The baffle is designed for a Ritchey-Chirtien (R-C) system and the model is built in the TracePro software for analysis. With the contrast of different models and the designs, the results show that the consideration of the scattering is more accurate, the effect of the outer baffle is better, and the point source transmittance (PST) of the system is lower than others.

A wavelength-division demultiplexer based on two-dimensional triangular lattice photonic crystals is proposed. This structure is composed of line-defect waveguides, ring resonators and point-defect nanocavities. The characteristics of line-defect waveguide are investigated via the method of the plane-wave expansion, and the projected band diagrams of line-defect waveguide are derived. Then appropriate parameters are obtained after a lot of simulations of the fine tuning of local components and the whole device. The transmission characteristics of light with different wavelengths in the photonic crystals demultiplexer are analyzed via the finite-difference time-domain (FDTD) method, and the resulting electric fields are also given. The results show the ability of wavelength-division demultiplexing between 1271 nm and 1291 nm with this device. Besides, six extra dielectric rods are added to enhance the transmission of the ring cavity, and by adding three pairs of dielectric rods at the entrance port, the total output efficiency of the system is increased.

A photonic crystal coupling structure is designed by introducing two parallel single-mode defect waveguides with the spacing of one row coupling rods in the two-dimensional (2D) triangular lattice array. By modulating the refractive index of some coupling rods, an optical switch based on coupled heterostructure photonic-crystal waveguides is constructed. The coupling lengths for different refractive indices of coupling rods at different frequencies are calculated to determine optimal structural parameters for the switch by the plane-wave expansion method and the principle of directional coupling. The effect of variations in the refractive index of the coupling rods and the position effect of the heterostructure coupled waveguides on the signal output channel are analyzed by using finite different time domain method. The simulation results show that it is an effective way to realize the switch function by appropriately tuning the refractive index of some coupling rods. The influence of the random distribution of the heterostructure on the switch is modest, which may contribute to the research over new kinds of optical filters, directional couplers, wavelength division multiplexers, optical switches and other photonic devices.

The subwavelength imaging properties of the two-dimensional square-lattice and triangular-lattice photonic crystals consisting of square metals immersed in the silicon background are studied by the finite-difference time-domain method. The Drude model is adopted to describe the metal′s dispersion characteristics, which is in a good agreement with the metal′s actual permittivity for the near-infrared wavelengths. Subwavelength imaging for the wavelength around 1550 nm is obtained through designing the parameters of the above two structures. It is found that the influence of metal′s absorption to the incident light can degrade the image spot′s intensity for a little degree, but it is trivial to degrade the subwavelength image′s quality. Compared with the traditional photonic crystal subwavelength-imaging devices consisting of air holes immersed in silicon, this kind of all-solid photonic crystal device consisting of metals immersed in silicon is more stable and can be actually applied in the complex all-optical integrated circuits.

A forward image displacement compensation device is designed and its feasibility for area scan color CCD airborne mapping camera is researched to improve the ground pixel resolution and the mapping accuracy. The effect of intrinsic and extrinsic parameters on image point during forward image displacement compensation is emphatically analyzed based on imaging relation of central projection, and the feasibility of the forward image displacement compensation for airborne mapping camera is verified. The compensation device, which is based on constant-diameter conjugate cam is designed and factors′ affecting the accuracy of aerial photogrammetry are studied. The rectified method is proposed by using affine transformation. Experimental results show that the rectified accuracy is 0.001 mm, and the proposed method of forward image displacement compensation is correct.

An optical surface plasma wave resonance (SPR) sensor based on the built-in modulation layer structure is studied. A kind of photoelectric composite film with unique performance is constituted by coating optical transparent films with different thicknesses and properties between the gold film and the fiber core, as internal modulation layer. It can adjust both the evanescent wave vector and gold film surface plasma oscillation wave vector, and then control resonance effect to provide a basis for sensitivity adjustment. Numerical simulation is done on the attribute of built-in modulation layer structure optical fiber SPR resonance incentive model using the finite difference time domain method. On this basis, a built-in modulation layer type optical fiber SPR sensor probe is developed for liquid refractive index measurement. The experiment results show that as the refractive index increases, the SPR resonance spectrum shifts to the long wave direction, in refractive index range from 1.335 to 1.392. The sensitivity can reach to 2263.1 nm/RIU, which is two times of conventional optical fiber SPR sensor based on the fiber core-gold film-environment medium three layer structure. All show that this new sensor can meet the needs of the environment index test much better.

In order to achieve high frame frequency, high dynamic range (DR) and low data quantity of visual information accurately, an implementation method of real-time vision sensor based on address-event representation is proposed. The readout data quantity and time-based information distortions decrease, benefitting from AER, adjustable row arbitration and time stamp. The method can detect light-intensity change by changing detector circuits and quantify the light intensity changes by double sampling pulse width modulation (PWM) circuits. The simulated results show that in the illumination conditions of 100 lx and 10 lx, the minimum equivalent frame frequency is 1000 frame/s and 100 frame/s, respectively. DR can reach 133 dB, and vision DR is 48.16 dB. The output can be decreased by 11.61%~42.74% compared with previous one. It proves that the proposed method can perform real-time optical signal capturing, processing and readout as well as be applied to the field of high-speed and high DR image and vision.

Taking Monte-Carlo method to simulate the aerosol aggregate particles and discussing the porosity characteristics of aggregate particles, the effects of spatial shape and number of original particles on the porosity and effective refractive index of aggregate particles are analyzed. According to the electrical structures of substance, the aerosol aggregates particle are dispersed into a series of dipoles, and by discrete dipole approximation method, the statistical average values of scattering, absorption and extinction cross sections of aerosol aggregate particles with different porosities are obtained. The results show that the porosity of aerosol aggregate particles significantly depends on the spatial shape and number of original particles of aerosol aggregate particles. The effective refractive index, absorption, scattering and extinction cross section decrease with the porosity increasing. The findings can provide a reference for a comprehensive understanding of the optical properties of aerosol particles, and for the optical property of some coating materials by changing the porosity of aggregate particles in the coating material. This affects the effective refractive index of the coating material so that the light scattering and absorption of the coating material are changed.

Interferometric imaging spectrometer has the advantage of high flux, high spectral resolution and high target resolution when it is used for narrow-band hyperspectral imaging detection. When the fringe pattern is sampled according to the Nyquist law, it produces large data redundancy which increases the data of Fourier transform and affects the spectrum recovery efficiency. To improve the recovery efficiency of interferometric imaging spectrometer, a narrow-band compressive sampling method based on the transmittance function of optical band-pass filter is described after analyzing the Fourier transform characteristics of narrow-band spectrum. By introducing different parameters of the filter and aliasing parameter, we can get compressive sampling frequency of narrow-band spectrum with different recovery accuracy. Together with the optical multi-band-pass narrow-band filter, we can obtain multiple-band spectrums information of the target through direct compressive sampling in order to avoid the by-band detection and to improve the detection efficiency. The proposed method is verified by simulation and experiment. As a result, the recovery narrow-band spectrum is consistent with the target spectrum.

The absorption of NO2 samples in the region of 436~470 nm was measured by incoherent broadband cavity enhanced absorption spectroscopy (IBBCEAS) with a blue light emitting diode (LED) to demonstrate the performance of IBBCEAS. Mirror reflectivity at 430~490 nm is determined from the changes in transmitted intensity through the cavity due to Rayleigh scattering when the cavity is filled with pure N2 and He, and validated with the help of the absorption at 477 nm of O2-O2 collisional pair in pure oxygen. The maximum mirror reflectivity of 0.99937 is found at 461 nm, which corresponds to an effective path length of about 1.17 km based on a 73.5 cm-long cavity. Detection sensitivity (1σ) of 0.25×10-9 with an acquisition time of 20 s is achieved. The absorptions of NO2 and O2-O2 collisional pair in ambient air are simultaneously measured by IBBCEAS in open-path mode. Measuring results demonstrate that the performance of the IBBCEAS instrument deteriorats due to aerosol extinction. It is a possible solution to realize in situ calibration of absorption light path of IBBCEAS instrument by measuring O2-O2 in atmospheric air.

HfO2 films are deposited by electron beam evaporation at a deposition rate of 0.03 nm/s and deposition temperature of 200 ℃ on K9 glass substrates. The films are observed to show a mixed structure of monoclinic and orthorhombic phase through X-ray diffraction and monoclinic phase is of obvious advantages. The structure parameters a, b, c and angel β of monoclinic HfO2 films are obtained using Jade5 software, based on which the crystal structure model is built. While solid crystal monoclinic HfO2 model is built to compare with the thin film one. Elastic stiffness constants of monoclinic HfO2 thin film and solid crystal are investigated using the plane waves ultrasoft pseudopotential technique based on the density functional theory (DFT) under two different exchange correlation functions of local density approximation (LDA) CA-PZ and generalized gradient approximation (GGA) PBE. Reuss, Voigt and Hill theories are used to estimate the bulk, shear and average Young′s moduli and Possion ratio for polycrystalline HfO2 thin film and solid crystal. In addition, the Young′s moduli in different orientations are also calculated.

The spatial-temporal property of ultrashort pulse is greatly influenced by optical aberrations, manufacturing surface-profile errors as well as element decenter and tilts when propagating through real optics. Hence it is necessary to develop a powerful analytic tool to simulate these effects. An efficient numerical algorithm based on a combination of wave theories and geometrical ray-tracing to simulate the propagation of ultrashort laser pulse through real optics is proposed. Using this tool, the spatial-temporal evolution of a Gaussian temporal envelope pulses with initial durations of 30 fs and a carrier wavelength of 800 nm through a specific real optics is modeled, in which both the geometrical aberrations and manufacturing surface-profile errors of the optical elements are considered. Consequently, a comparative analysis on focusing properties of the pulse such as temporal envelope and focal size retrieved by simulation and experimental measurement is carried out at the focus for homogeneous illumination beams.

Propagation model of hard X-ray beams from partially coherent synchrotron source through different optical elements is proposed based on the coherent mode decomposition of Gaussian-Schell model and wave-front propagation. The fractional Talbot effect of phase gratings illuminated by focused partially coherent synchrotron radiation is simulated. Both the focusing beam′s intensity distribution and the coherence properties are obtained. And the self-imaging of gratings illuminated by defocused beam is analyzed. The influences of different factors on the shape of Talbot images at different fractional Talbot distances are analyzed through the comparison of the self-imaging fringes in the diffraction pattern of gratings illuminated by collimated beam. The diffraction images of rectangular phase gratings are submitted to a Fourier transform procedure, yielding the Fourier coefficients of different orders as a function of propagation distance, and the information on the lateral coherence of the beam is obtained.