Based on the generalized Huygens-Fresnel principle and the modified Von Karmon spectrum mode, the analytic expression of mean intensity of partially coherent Gaussian- Schell model (GSM) beam, which is propagating in the atmospheric turbulence along an uplink path, is derived. The analytical formula of mean intensity of GSM beam which is echoed through corner reflector and propagated along a downlink path to the receiver is obtained and normalized. The change of mean intensity of GSM beam when it is propagating along an uplink and a downlink path is analyzed, in the case that the transmitter and the receiver are located on the same height. The results of numerical analysis show that the influence of turbulence to collimated beam is smaller than it is to focused beam, when they propagate along a double slant path in the atmospheric turbulence. On the receiver, with the increase of corner reflector radius, the axial normalized intensity first increases, and eventually tends to be constant. The axial normalized intensity decreases with the increase of turbulence inner-scale, but nearly has no change with the increase of turbulence outer-scale.

In recent years, the research of image processing is developed from traditional two dimensions (2D) to three dimensions (3D) or even more dimensions. However, the existing segmentation methods are mainly based on 2D image processing, and more effective 3D image segmentation methods are expected. An adaptive 3D image segmentation method based on vector quantization (VQ) that can effectively utilize the spatial information of the volume data of the 3D image is proposed. In the method, a preprocessing is conducted on the 3D image, including volume interpolation, dividing of the 3D image into small sub-cubic blocks (sub-cubes), and classification of the sub- cubes into two patterns, the edge pattern and non- edge pattern. The non- edge pattern sub- cubes are segmented by using the VQ technique and the edge pattern sub- cubes are classified in pixel based on the segmentation results of non-edge pattern sub-cubes. In order to determine the segmentation number adaptively, an optimal codebook searching algorithm is designed for the VQ approach. Experiments are conducted by using both the simulation samples and real human brain magnetic resonance imaging (MRI) images from the IBSR database and the effectiveness of the proposed method is validated by the experimental results. The experiments are also performed on the MRI images of the same patient in different treatment periods, which can provide the varied 3D information about the focus parts in different times that is valuable for clinical diagnosis in medical practice.

A kind of novel fabrication system of array optical fiber gratings is designed, which can make multiwavelength array optical fiber gratings on 8-core ribbon optical fiber. The principle of this system is as follows: the ribbon optical fiber is clamped by the specially-designed fixture; tension is applied on ribbon optical fiber to control and change the resonant wavelength by electrically controlled displacement platform; optical fibers are exposed under ultraviolet (UV) laser one by one; Hamming apodization is employed at the same time. Array optical fiber Bragg gratings with 0.2 nm bandwidth, wavelength interval less than 0.5 nm, wavelength deviation less than ±0.05 nm and reflectivigy from 80% to 85% on ribbon optical fiber are successfully obtained by the above system. This kind of technoloty is easy to adjust the parameters of the optical fiber gratings and has more automation.

A pattern recognition method based on ensemble empirical mode decomposition (EEMD) is proposed for the non-stationary features of output signal in the fiber-optic intrusion monitoring system. The system based on the principle of Mach-Zehnder interferometer and four single-mode optical fibers in the cable are utilized to build up the distributed crosstalk sensor, by which the real-time detection of abnormal events can be realized. The vibration signals are decomposed into a series of intrinsic mode functions (IMF) using the EEMD algorithm with self-adaptability. According to the characteristics of the various vibration signal intensities, a method using the EEMD energy entropy to eliminate the disturbance of non-intrusion events is proposed. Double support vector machine is built to identify the intrusion type. The experimental results illustrate that this method can evidently get rid of the non-intrusion disturbance and effectively discern different intrusion events such as fence-climbing, cableknocking and other signals. The correct recognition rate in average is greater than 92%. What′s more, the alarm rate is increased and the false alarm rate is reduced in the system.

Compared with the conventional training symbols-based channel equalization method, the blind channel equalization method based on the independent component analysis (ICA) improves considerably the spectral efficiency of the polarization-division-multiplexing coherent-optical orthogonal-frequency-division-multiplexing (PDM- CO- OFDM) systems. However, the blind channel estimation requires the computations of the channel frequency response on subcarrier basis and needs dozens of iterations to converge. To reduce its computational complexity, on the basis of the channel equalization using ICA, a blind channel equalization method is proposed. It is performed by using ICA with adaptive variable step, and the separation step method enhances the convergence rate of the iterative algorithm greatly. For 100 Gb/s PDM-CO-OFDM with 16 quadrature amplitude modulation (16 QAM), it is proved by the simulation results that its convergence rate improves more than five times, compared with the channel equation method by using ICA with fixed iterative step. This method can be used to realize high efficiency channel equalization in the future high speed PDM-CO-OFDM system receivers.

In the detection system, the long distance optical fiber vibration can be detected by phase-sensitive optical time domain reflect technique. However, the reflected signals include clutters and noises, which leads to a high false alarm rate. A two- level detection algorithm, which can maintain constant false alarm rate, is proposed, including cell average constant false alarm rate (CA- CFAR) and ordered statistics constant false alarm rate (OS- CFAR) which work in serial ways, and the detection speed of CA- CFAR and the performance of OS-CFAR are conserved, respectively. Monte Carlo simulation is applied to determine the threshold of twolevel detection. Finally, Monte Carlo simulation and the experiment on the scene are applied to analyze the performance of the algorithm, which proves the feasibility and effectiveness.

In order to realize temperature-stable fiber Bragg grating (FBG) sensing demodulation, a calibration method of real-time composite wavelength references using Fabry-Pérot (F-P) etalon and acetylene gas cell is proposed. The temperature drift properties of F-P etalon transmitted spectrum and acetylene gas cell absorption spectrum are analyzed. The experiment system is developed to test temperature drift property of F- P etalon transmitted spectrum. The experiment shows that the average temperature sensitivity of F-P etalon spectral line is 1.16 pm/℃ and the temperature repeatability error can be up to 13.0 pm. Temperature stability of demodulation both using F-P etalon as wavelength reference and composite wavelength references is studied. The experimental results show that under temperature cycle from 0 ℃ to 55 ℃, the range of variation using single wavelength reference is ±32.7 pm, and the standard deviation is 20.7 pm. However, the range of variation using composite wavelength references can be ± 1.2 pm, and the standard deviation is 0.39 pm. The temperature stability of variation range increases 27 times.

The factors that affect the temperature sensitivity of typical polarization- maintaining photonic crystal fibers (PM-PCF) are analyzed. By using the finite elements method, the influence of temperature on the birefringence of the typical solid core PM- PCF is studied, which mainly includes thermo- optic effects and thermal expansion. The results show that the thermo- optic effects can be neglected and the temperature sensitivity of birefringence can be represented only by a polynomial function of the center distance of adjacent air holes Λ under the working temperature from - 150 ℃ to 150 ℃ . The birefringence increases with Λ and becomes zero at Λ =5.16 μm. The compact hybrid Sagnac interferometer is used to measure the birefringence of five PM-PCF samples with different Λ under different temperatures. The experimental results conform well to the simulation.

Conventionally, for a direct- detection 3D imaging light detection and ranging (LIDAR) system, it′s impossible to directly and accurately determine the pixel-wise signal-acquisition time in the case that the scene properties are unknown. Thus, a time-of-flight depth sensor produces noisy range data due to different scene properties such as surface materials and reflectivity, frequently including either a saturated or severely noisy depth estimated. A photon-counting adaptive depth imaging strategy for 3D imaging LIDAR is presented. By improving the traditional imaging model based on the maximum likelihood estimation algorithm, an appropriate signalacquisition time is adaptively selected, and then determine an optimal depth for each pixel. Experiment demonstrates that the proposed algorithm can be more quick and more accurate to reconstruct the scene depth images even in the low light-level environment.

Aperture-scanning Fourier ptychography technology shows great potential capacity in the fields of threedimensional holographic refocusing and super- resolution macroscopic imaging. The influence of some key parameters of the technique on recovering quality is investigated. The influences of overlap ratio and size of circular apertures are studied based on light field simulation experiments using aperture-scanning Fourier ptychography iterative algorithm. The simulation results show that there is a threshold of overlap ratio under the circumstance of same aperture size, when overlap ratio is greater than the threshold, the recovering quality increases with overlap ratio raising. Under the circumstance of same overlap ratio, the recovering quality increases with reduction of the aperture size. The research results can provide guiding role for optimizing aperture parameter in the further applications of aperture-scanning Fourier ptychography.

On the basis of physiological and physical properties of rice seeds with different aging time, an infrared thermal model for testing rice seed germination rate by multi-scale wavelet transform and grey neural network is proposed to realize fast and non-destructive detection of rice seed germination rate, and to solve the problems of long experimental period, complex operation resulted from traditional germination rate test methods. 144 samples are extracted from germ section of different rice seeds. Detail signal of the third layer wavelet decomposition (d3) is the greatest contribution by analyzing approximation signal and detail signal through a multi-scale wavelet transform. So the detail signal of the third layer wavelet decomposition is used as the model input, and the samples are randomly divided into a calibration set (96 samples) and a prediction set (48 samples). The infrared thermal difference of rice seeds with different aging time is analyzed and compared through partial least squares (PLS), back propagation (BP) neural network, radial basis function neural network (RBFNN) and grey neural network (GNN) to establish infrared thermal prediction models of rice seed germination rate. The results show that the optimal model of germination rate is constructed by GNN artificial neural network, by which the correlation coefficient (RC) and standard deviation (SEC) of the calibration set are 0.9619 and 2.5013 respectively, and the correlation coefficient (RP) and standard deviation (SEP) of the prediction set are 0.9554 and 2.4172 respectively, the relevance reaches a higher level and the error is small. The experimental results show that adopting wavelet decomposition and GNN to establish the infrared thermal prediction model of rice seed germination rate is feasible.

Multi-beam interference technique has been widely used to fabricate large-scale periodic structures. The materials also extend from inorganic to organic. According to the interference theory, we simulate the intensity distribution of three-beam interference. With the same incident angle, we realize two dimensional‘air-hole’(SS-S, P-P-P) and‘dielectric-cylinder’(C-C-C) periodic structures only by changing the polarization configuration of interference beams. Meanwhile, because the organic materials have response properties to the polarization of light, we also analyze the interference polarization distribution. And we find that in one Wigner-Seitz cell, the linear polarization configuration results to the periodic polarization distribution: from linear polarization, to elliptic polarization, to circular polarization, instead of linear polarization.

A real-time digital image correlation method is realized using the seed point-based parallel method and inverse compositional Gauss-Newton algorithm. According to the continuity of measured area, the single-seed parallel method and multiple-seed parallel method are described respectively. The results indicate that the multipleseed parallel method can be effectively used to measure regions separated by poorly correlated data. The proposed method is successfully applied to quasi-static test in civil engineering, obtaining the full-field displacement and strain distribution in real time. Conclusions can be obtained from the experiment of measuring the bond- slip relationship of carbon fiber reinforced plastic(CFRP) sheet-steel interface: the method can be used to gain the fullfield deformation and the location of stripping area can be determined directly; the stripping process of interface can be recorded in real time and bond-slip relationship of interface can be obtained directly, which provides an effective way to measure and analyze the behavior of fiber reinforced plastic(FRP) consolidating structure. The realtime measurement will help to further promote digital image correlation method in civil engineering.

The formula of air refractive index used in this paper for optical trace computing is described in detail. Following the changing of image quality of spherical mirrors with different R is analyzed caused by air temperature layered in horizontal and vertical testing cases. The temperature gradient effects for off-axis near parabolic segment with Φ1.5 m, off-axis length 12 m are calculated and analyzed in horizontal and vertical test status. Finally, the influence of image quality by air temperature gradient distribution for large parabolic mirror with aperture Φ4 m, focal ratio f/2 with the states above mentioned is calculated and simulated. The results above all indicate that, in general, the influence level for image quality in horizontal test is much greater than vertical case, moreover, the air temperature factors should be considered in vertical optical testing in large aperture and fast focal ratio parabolic testing.

In order to test optical figure of aspheric off-axis segments of extremely large telescope, we present a new optical testing method. Take advantages of transmission and diffraction nulls, the aspheric departure is accommodated by both aplanatic lens and computer generated holograms. For plenty of large off-axis aspherical mirrors, only one optical path needs to be built. Different segments will be measured by replacing computer generated hologram (CGH). Design results show that, for different off-axis magnitudes as 2.5 m, 8 m and 14.5 m of a primary mirror with 60 m vertex curvature radius, conic constant K=-1.000954, parent mirror diameter Φ30 m, segment diameter Φ1.5 m, all can achieve self-collimation null tests in one light path structure.

A method based on contour model tracking to estimate the homograhpy for the textureless object in the clutter scene is proposed. The initial estimation of the transformation is obtained in the framework of random sample consensus (RANSAC). The optimized homography solution is obtained by minimizing the normal distance. To calculate the initial transformation quickly and robustly, random three line segments conforming to the certain geometry constraint are utilized to solve the assumptive transformation relation. The transformation relation with the minimal errors are picked out as the homographic initial value. To overcome the issue that the mismatches of the model and image lines in the complicated background may lead to the failure of the homography optimization, in the process of matches of the model and image points, multiple image points matches are retained for each model sample point. In the weighting process for sample point, due to the use of the property of the sample point as well as the relation to the neighbor points, the robustness of method is enhanced effectively. Experimental results show that the proposed method can realize the optimized solution of homography in the complicated background. Contrast with the traditional method, the proposed method can overcome the influence induced by the complex background effectively and optimize the homography parameters for textureless objects successfully.

A kind of transparent electrodes with broadband transmission are optimized using the finte different time domain (FDTD) algorithm.The transmissions of the designed Ag, Au and Cu mesh arrays are all about 70% in visible (Vis) band and 90% in near-infrared (NIR) band. In order to improve effectiveness-cost and technology compatibility of transparent electrodes, Cu is a suitable candidate. The effects of packaging materials, roughnesses and error widths of Cu nanostripes are analyzed.The results show that with the increasing refraction indices of packaging materials and roughnesses of Cu nanostripes, the transmissions increase in NIR band and Vis band, respectively, and the NIR bandwidths decrease. As the error widths of Cu nanostripes increase, the transmission properties in Vis-NIR band reduce and NIR bandwidths decrease. The transmissions are high in Vis and NIR bands as the refraction index of packaging material, room mean square of roughness and error width of Cu nanostripes are lower than 1.5, 8 and 20 nm, respectively. The conclusions are helpful for developing transparent electrode of photoelectric devices with broadband transmission.

A systematic comparative study on the natural diamonds, the natural diamonds after annealing and irradiation and synthetic diamonds prepared by chemical vapor deposition (CVD) or high pressure and high temperature (HTHP) are investigated by DiamondView combined with UV-Vis-NIR absorption spectra and Fourier transform infrared spectra. The results show that the fluorescence′s color of colorless or near-colorless natural diamond shows a single blue color with no phosphorescence, closure or misclosure ring-structural growth lines or irregular lines are existed in theirs corresponding fluorescence images. Some natural diamonds have blue fluorescence and greenish blue phosphorescence. Meanwhile, parts of natural diamonds have the characteristic with no fluorescence and no phosphorescence, most of CVD synthetic diamonds have the characteristics of fluorescence and phosphorescence. Therefore, it is not scientific to identify of natural and synthetic diamonds based on theirs phosphorescence. The fluorescence′s color of natural diamond treated by irradiation and heat treatment display the other color expect blue. After irradiated, diamonds show large variations in their fluorescence patterns, particularly in the fluorescence′s color. Furthermore, the fluorescence color show mixed-color because of the color center defect resulted from irradiation. It should point out that the instruments of UV-Vis-NIR spectrometer and DiamondViewTM are very powerful tool for studying irradiation in all sorts of diamonds until now. Unique fluorescence′s characteristics with parallel lamellar growth striations appear in the table and pavilion of the majority of CVD synthetic diamonds and are powerful evidences to identify CVD synthetic diamonds, which correlation with the preparative technique of chemical vapor deposition. Additionally, the DiamondViewTM images of CVD diamonds display light blue phosphorescent.

In order to meet the requirements of small airborne remote sensing platform for imaging spectrometer with high resolution and miniaturization, an airborne light and compact high resolution imaging spectrometer system is designed using the imaging spectrometer structure form combined flat-field Schwarzschild telescope system with Offner spectral imaging system. The working wavelength is from 0.4 to 2.5 μm, the relateive aperture is 1/3, and the field of view is 7.2°. The characteristics and aberration correction principles of Schwarzschild telescope system and Offner spectral imaging system are analyzed. Then the ZEMAX software is used for ray tracing and optimization. The modulation transfer function (MTF) curve and spot diagram are given and evaluated. The design and analysis results show that the airborne light and compact high resolution imaging spectrometer optical system can meet spectral resolution of 5 nm and spatial resolution of 0.6 m. Optical system has simple and compact structure and excellent image quality that approaching to the diffraction limit. It can realize the high resolution and miniaturization of system and meet the application requirement of airborne remote sensing.

In order to increase the illuminance uniformity of the source used in the liquid crystal display(LCD) detection, based on nonimaging optics, a method of a light emitting diode (LED) source with large aperture and small view angle is proposed in this paper. The illumination system of this source is realized by array of LEDs and the lenses. For a single LED, Fresnel lens is designed to collimate the beam with small view anglethen, the optimal distance of the array is obtained by deducing the uniform illumination condition and optimizing it with TracePro. Finally, the uniform rectangular illumination is achieved through splicing superposition the spot on the illuminating surface. The illumination source consists of 12×9 optical units which are arranged in uniform rectangle, and the distance between every two optical units is 30 mm. The simulation results show that the viewing angle of the source is less than ±10°. At the target surface 170 mm away from the source, the average illuminance is greater than 45000 lx, and the nonuniformity is 3.8%. All of the indexes meet the design requirements. Comparing with the existed source, the arrayed source designed in this paper has obvious advantages whether on the average illuminance or the illuminance uniformity.

To achieve the target of uniform illumination of exposure system, a design method of uniform lighting system with array module is proposed based on non-imaging optics. Firstly, through the design of single lens, the half divergence and the array distance are calculated roughly.Secondly, the Scheme macro language and the optimization engine in TracePro software are used in combination to achieve the optimization of the array distance. And then, the design of uniform illumination of entire optical system can be realized. In this paper, the STS-DA1-2394E (Cat.No.130319) UV LED of Nichia′s is used as the light source, and the number of array module is 5. The array distance of lateral and vertical is respectively 28 mm and 24 mm. The results of simulation by TracePro software and experimental show that non-uniformity and collimation angle are less than 5% and 4° respectively, at a distance of 300 mm from the light source.

Three-order coma is one of the main aberration types to produce mirror disorders of coaxial threemirror astigmatism (TMA) optical system. The variation characteristics of coma in perturbed coaxial TMA optical system is analyzed using vector aberration theory. The solving method and formula of aberration displacement vectors of secondary mirror and three mirror is proposed, and the coma increment coefficient formula caused by secondary mirror and three mirror of system is deduced. It is proved that the three-order coma produced by decenter of tertiary mirror in X-Y plane can be totally compensated by constant ratio of decenter amount of secondary mirror. The coma-free compensation condition of secondary is proposed, and the coma-free decenter conditions of secondary mirror and tertiary mirror are proposed respectively. Two examples of disordered three mirror in coaxial TMA optical system are used to calculate the coma-free compensation condition. Under the condition of coma-free compensate, the all field of view mean coma increment is only 0.6% and 1.9% before disorder, which shows the validity of the proposed coma-free compensation condition.

High-speed aircrafts which use splicing optical windows can reduce the drag and radar reflectivity. But they will cause the incident wave at the front of the various window glass splited, and may cause the degradation of the optical system modulation transfer function (MTF) and the decline and splitting of the point spread function (PSF). In severe cases it will affect the resolution of the system. Therefore, analysis of the effect of stitched windows on the optical systems has an important reference value to the optical system design using stitched windows. Use Zemax software to build stitched window model, we simplify the process of the analysis. The results show that when the incident light is divided to produce a specific optical path difference, the MTF and PSF will decline and split. The serious split of the PSF will decrease the image quality of the optical system. Reasonable choice to the stitched window parameter can mitigate this effect.

The point-to-point laser communication technology has been more mature.However,network communication problems among different platforms are still unable to be solved.A new design method of the optical antenna networking communication is put forward,which can achieve multi- point synchronous duplex laser communication.Firstly,the principle of optical antenna is analyzed and validated by modeling and simulation.Then,the structure design and the working mode of the optical antenna are presented.Finally,the working range for duplex communication and optical antenna multi-platform is analyzed through optimal control algorithm.Assumes the rotational parabolic aperture is 300 mm,this system can achieve 360° azimuth and over 90°elevation range.For network communication requirements of GEO（geosychronons earth orbit）-GEO-OGS（optical ground station）,the initial optical antenna is intended.It has an important meaning for promoting the laser communication application technology in a wide range of areas.

The head-mounted display used for virtual reality demands an optical system with large field of view and exit pupil diameter, which has the characteristics of less weight and small total length to satisfy these requirements. This article presents a design method of the head-mounted display (HMD) optical system based on the primary aberration theory. Through this method, a two- piece optical system by utilizing polymethyl methacrylate (PMMA) and polycarbonate (PC) is designed. The exit pupil diameter of the proposed system is 8 mm and its field of view is 70°. The total length is less than 70 mm, and the weight of the system is less than 30 g. The full-field relative illumination is greater than 0.4. Its axis and off-axis aberrations have been effectively corrected. The root mean square (RMS) radius of the marginal field is about 70 mm, modulation transfer function (MTF) curves have a uniform distribution, while the MTF values of the central field and the marginal field are about 0.6 and 0.4 at 8 cycle/mm, respectively. The maximum distortion of the system is less than 2%. The manufactured optical system has satisfactory image quantities according to the quantity inspection by the standard resolution panel.

Uniform illumination free-form surface lens has been widely used in the light emitting diode (LED) lighting. However, due to modeling error in traditional freeform surface solution based on geometrical approximation, the surface shape can not be solved accurately and result in the decline of illumination uniformity. A method of error analysis and compensation algorithm is proposed. The relationship between emitted light angle error and free-form surface error is established, combined with the ray tracing, quantifying and correcting for surface error accurately. According to the method above, it is suggested that the compensation design of landscape lighting lens in which the working distance of the lens is 1000 mm and target panel diameter is 200 mm. The simulation result shows that after importing the lens modeling into Lighttools software demonstrate, compared with the traditional design method, the illumination uniformity is increased from 68.0% to 98.5% under the condition of point light source. And the uniformity is reached up to 91.8% with the diameter of 160 mm lighting area and the condition of 1mm×1mm size of the LED source. The optimized lens has good practicability.

Existing scanning fuselage conformal optical systems all contain dynamic correctors. However, the stability of the optical system with dynamic corrector is poor and the structure is complex. To improve the stability of fuselage conformal optical systems for application and simplify the system structure, a static correction method used in fuselage conformal optical system which is based on freeform correctors is proposed. Based on aircraft applications, a conformal optical system with 3° field of view and 30° field of regard is designed by the method. The design results show that by adding two tilted freeform correctors behind the tilted conformal window, the static aberration and dynamic aberration introduced by the conformal window are corrected and the image quality of the conformal optical system is near the diffraction limit at every field of regard. Moreover, compared with dynamic correctors, the static freeform correctors enhance the stability of the optical system and simplify the system structure.

The emission spectrum of light emitting diode (LED) are calculated by using the LED spectral model of Ohno, and then the spectral combination of multi-LEDs has been investigated theoretically and experimentally. In the experiment, the warm white light, which is obtained by blue LED die exciting green and orange phosphor, and red, cyan, blue LED light are mixed. By respectively controlling the duty ratio of the pulse width modulation (PWM) signals, the drive currents and luminous flux of each LED can be adjusted. A mixed white light source with ultra-high color rendering index has been realized for the first time, whose color temperature can be tunable within the range of 2700 K to 6500 K, Ra is between 95 to 98, all special CRIs (R1~R15) are more than 90, and luminous efficiency of radiation (LER) is between 286 lm/W to 336 lm/W .The consistency of experimental measurements and theoretical simulation are very well.

In order to research the problems which optical correlator can not recognize with the rotating target. It is proposed that by using the plane mirror group we can obtain the target image and recognize with the mirror image of the template image. In the optical system of acquire target, inserting a polygonal prism which is enclosed by plurality of plane mirror, it can make the target to produce a set of different angles mirror image. The similar angle mirror image can be found from a set of mirror image by different rotation angle target, and correlation peak is acquired when such target image and template are correlated. Experimental results show that mirror image of the rotating target obtained by the plane mirror group as the target image, is an effective way to resolve problem that optical correlator recognize with the target.

Conversion behavior of optical bistability and optical bistability/multistability in coupled semiconductor double quantum wells with the structure of V-type is investigated. It is shown that the threshold of optical bistability strongly depends on intensity of incoherent pump field and relative phase under the condition of existence of spontaneous radiation coherence. Moreover, conversion between optical bistability and multistability can be easily achieved just by the phase modulation.

In a nonlinear optomechanical system which contains a Kerr medium and a degenerate optical parametric amplifier (OPA), optical bistability and entanglement are affected largely by these two kinds of medium. When adjusting the coupling constant of nonlinear crystal and the cavity field, the nonlinear gain of OPA crystal and the intensity of incident light have similar effects on the optical bistability, while the third-order nonlinear susceptibility of Kerr medium has obviously different effects. The calculation results of entanglement in this system show that the nonlinear gain coefficient of OPA crystal can increase the entanglement between cavity field and vibrating mirror, while the third-order nonlinear susceptibility of Kerr medium can reduce the entanglement.

In order to evaluate the effective detection distance of bio-aerosols and sensitivity to the concentration of the bio-aerosols for the laser induced bio-aerosols fluorescence lidar. On the basis of elaborating lidar measuring principle, a fluorescence lidar employing a Nd: YAG laser at 355 nm as a transmitter is designed for biological aerosol concentration detection. The signal-to-noise ratio (SNR) of bio-aerosols fluorescence echo signal is simulated based on the main parameters, such as pulse energy, pulse number, filter bandwidth, diameter of telescope, field of view of telescope and inelastic scattering cross-section of bio-aerosols particles. With the uncertainty of less than 10%, theoretical analysis results show that the system is capable of measuring bio-aerosols with a mass fraction of 10-12 up to an effective detection distance of 1.0 km and 7.8 km at daytime and nighttime, respectively. Moreover, with a certain detection rang of 0.5 km, the fluorescence lidar is able to detect bio-aerosols at a minimum mass fraction of 1.8×10-13 at daytime and 1.0×10-14 at nighttime. Simulated results are helpful to understand the optimal parameters of laser induced fluorescence lidar and also the best experimental environment of the system, and then realize effective detect to bio-aerosols.

In order to realize the echo online extraction for diffuse reflection laser ranging when echo photons are blocked by a large amount of noise photons, an echo online extraction method based on time correlation is proposed for diffuse reflection laser ranging system. Based on the characteristics of time correlation for diffuse reflection laser ranging data, the extraction problem is simplified into n points searching problem. Next, the correctness of the extraction based on time correlation is verified. And the rules to select a proper n are given further through the trade-off between search cost and extraction accuracy. Then, the evaluation criteria for short-time linearity and adjacent similarity are given in detail. Finally, Genetic algorithm is adopted to realize parallel search for buffer data and online data, decreasing the search time as well as increasing the extraction accuracy of ranging data. The echo extraction for Yunnan Station′s experimental data show that the extraction method proposed has strong ability to extract echo signal from high noise background quickly, which provides a feasible way to realize the signal online extraction for diffuse reflection laser ranging.

Theoretical research and experimental simulation are carried out on the properties of corner cube array retroreflector. The optical path of the ray incident on a single pyramid is analyzed in detail. Meanwhile, the diffraction characteristics of two kinds of structures (triangular corner cube array and pentagonal corner cube array) are studied. The effect of pyramidal depth on the imaging quality of corner cube array is discussed, and the simulation results are given under the different parameters. The results provide theoretical foundation for the design of corner cube and its applying in the three-dimensional display.

Design method of traditional diffractive optical element (DOE) is only applicable to a single wavelength. But multiple DOEs are often required in the holographic projection display and color image generation, which is more complicated to greatly limit the application scope. A novel design method of DOE used for multi-wavelength simultaneity is present. The Gerchberg-Saxton (GS) algorithm is adopted to design individual DOE at every wavelength. And then individual DOE structure at the longest wavelength is regarded as the iterative side, in every pixel of which the integral 2π phase height is added. Structure compare the equivalent phase of the corresponding pixel with that of the individual structure at the other wavelengths. When squared distance is the least, the iteration is complete. This method is simulated and the parameters are analyzed by using Matlab. DOE structure is quantized to the 16- level, which validates the feasibility of this method in actual production.

A novel fiber grating radial pressure sensitivity enhanced scheme,which is encapsulated with ethylenevinyl acetate copolymer (EVA),is presented.The fiber grating is encapsulated into a half dumbbell-shaped sensing unit with EVA material and square steel.And the structure stress distribution and radial pressure response characteristics of the sensor are calculated theoretically with finite element software.Finally,an experiment system is established for verifying the sensing characteristics of the sensitivity enhanced optic fiber grating radial pressure sensors.The experiment results show that when the radial pressure is ranged from 0 to 0.3 N,the encapsulated sensors have excellent linearity to radial pressure.And the sensitivity is 100.74 times higher than that of naked optical fiber grating.Further more,after demodulation with the matching method,the sensitivity of the system can be up to 0.94 nm/N.The research results have an important reference significance for solving the practical engineering requirements for accurate measurement of micro radial strain.

Thermal aberration is one of the main reasons for imaging quality degradation of lithographic lens in working status. According to the structure feature of on-axis two-mirror high numerical aperture (NA)lithographic lens, a combination of element position shift and district heating method is proposed to compensate thermal aberration. The element position shift method takes advantage of element space, decentration and tilt to adjust the imaging quality; the district heating method takes advantage of the feature that the refractive index of optical material changes along with the temperature to control the temperature distribution on the lens and generate a controllable wavefront. The thermal aberration under dipole illumination model is compensated by the proposed method, and the wavefront aberration and distortion are recovered from 129.78 nm and 12.24 nm to 1.69 nm and 1.31 nm, respectively. The proposed method can basically recover the imaging quality of lens to design level.

A new method to measure the orientation of cold polar linear molecules using the relative intensity of the Q branch spectrum of the pendular state of linear molecules is presented. The relationship between the orientation of HCN-N2 and Q-branch intensity of pendular state spectrum of the C—H stretch of the ground state of HCN-N2 is studied, and it is found that the intensity of its Q branch spectrum increases with the increase of the electric field strength, but the intensity of the R- and P- branches decreases with the increase of the electric field strength. The relative intensity of the Q branch spectrum (ratio of spectral intensity of Q branch and total intensity of P, Q, R branches) can be used to represent the electric field intensity. Also, the study shows the orientation of the molecule increases with the increase of electric field strength. So it is proposed that the method which uses the relative intensity of the Q branch spectrum can be applied to measure the orientation of the polar molecule.

Baseline correction is an important step of spectral retrieving procedure for Fourier transform imaging spectrometer data processing, because preprocessing steps of spectral retrieving procedure, such as interference curve apodization and phase correction, need to be implemented after baseline correction is completed. A selfadaptive differential filtering method for baseline correction is presented. This method uses an iterative algorithm for dynamically adjusting its weighted mean filter window. The simulation results demonstrate that the filtering method can filter out the direct current trend more thoroughly. Analysis of the ultraviolet spectral data of latent fingerprint residues obtained by instrument in laboratory is made. The results indicate that within the working spectrum range of the instrument, the spectra obtained by the proposed baseline correction method are substantially consistent with the actual spectra. Since the method does not require a pre-selected mean filter window, it is selfadaptive. Moreover, the self-adaptive differential filtering method based on mean filter algorithm is simple and has high efficient iteration.

With digital imaging and spectral measurement, multispectral imaging technology is a new non-invasive technique to record optical information. Based on the analysis of the application of multispectral imaging in domestic and overseas cultural heritage field, simulated plate of Dunhuang mural pigments and modern Chinese paintings are analyzed using self-developed system at 300~1000 nm to prove its applicability. The results show that pigments with similar color can be identified quickly in multispectral images. Combined with laser Raman microspectroscopy, mineral phases in these pigments can be further determined. Meanwhile, the distribution of materials with ultraviolet induced visible fluorescence, the draft, the watermark in the painting can be well revealed. It is illustrated that various information of colored artworks can be obtained effectively by multispectral analysis, and the technique has good application foreground in the study of colored artworks.

Because conversion efficiency (CE) can characterize ultraviolet (UV) down-conversion light-emitting thin films accurately which is very useful in photoelectric devices, the research of CE is very crucial. An experimental determination of conversion efficiency of UV down- conversion light- emitting thin films based on using an integrating sphere to collect the photons is proposed, which solves the problem owing to disregarding anisotropy and wave-guiding effects in determining the angular distribution of the emission. A new computing method by using the emission spectrum of samples is also proposed, which is easy to compute. Demonstration experiments of Lumogen and Coronene, two fluorescent materials often applied in UV down- conversion field are made. Demonstration experiments show that this method is more reliable and more accurate, which should be recommended for computing CE in UV down-conversion research field.

The magnetic flux compression technique by explosive cylindrical implosion has the advantages of high loading pressure, small temperature increase during loading process as well as the ability of holding large volume samples. By the virtue of all these characteristics, it has wide applications in the fields of high pressure physics, new material synthesis and ultrahigh magnetic field condensed matter physics. The utility of ultrahigh speed photography technology in the experiment of magnetic flux compression by cylindrical implosion method is reported. The onedimensional and two-dimensional images of compression process of magnetic field with high temporal and spatial resolutions are obtained using ultrahigh speed framing photography and scanning photography techniques. The whole compression and rebound process as well as the interface instability phenomena are observed. By analyzing the dynamical curve of sleeve cylinder′ s diameter, the compression speed of magnetic flux is obtained. The experimental data is an important guideline for the research of future magnetic flux compression technology by cylindrical explosive implosion technique.

Human aberration plays an important role in visual function. So far, relevant research findings are obtained mainly under monocular viewing conditions. To investigate the effects of binocular aberrations on binocular visual functions, a binocular higher-order aberration correction and vision analysis system is established. The proposed system employs Hartmann wavefront sensors and 37-element deformable mirrors to measure and control binocular aberrations. Through the optimization of the controller gain, it realizes stable closed-loop control of binocular aberrations. The organic light-emitting diodes are used as stimulus display. The input signals are generated directly by computers, making it convenient to implement various visual function tests. Employing the proposed system, a preliminary stereo vision experiment is carried out, its vast potential in binocular visual function testing is demonstrated. The binocular higher-order aberration correction and vision analysis system provides essential technology and equipment support for further binocular visual function research in the future.