A subharmonic method was proposed based on the multi-order frequency grids dividing for the generation of the turbulent phase screen to compensate the low frequency components. Frequency grids were divided by multiple orders in the frequency domain of phase screen, and the frequency grids of each order were further finely subdivided, and then the frequency components in low frequency range which contribute the most to the turbulent spectrum could be compensated sufficiently. The phase structure function and the power spectrum of atmospheric turbulence were used to analyze the accuracy of the generated phase screen. Simulation results show that the discrepancy between the phase structure function derived from the generated phase screen and the theoretical value directly calculated from the turbulent spectrum is decreased by the increasing of the total number of frequency grid orders M, and frequency grid point number of each order N′xand N′y. For every group of M, N′xand N′y, there is an optimum value for frequency space before subdividing Δf1. By selecting M = 3, N′x=N′y=3 and Δf1=2 m-1, the phase structure function and the power spectrum of the screen can be quite closely to theory. The overall slope in the generated random phase screen reflects an accurate sampling of the low frequency components.

Based on the silicon bulk micromachining process, a micro programmable grating with tunable blazed angle was designed and optimized. The relative light intensity in the cases of different blazed angle and incident angle was theoretically calculated. Also, the far-field relative light intensity with the changing incident parameters was surveyed by adopting the COMSOL, a finite element simulation tool. The results show that: compared with the surface-micromachined gratings designed in our previous research, the efficient reflecting area is increased by more than 8%, reaching to 83.63%. The realized maximum blazed angle of the designed grating is 6.84°, and the maxmium diffraction efficiency can be 96.67% under the condition of normal incidence with the wavelength of 532nm and the blazed angle with a tunable range of 0-10°.

A phase recovery method based on sinusoidal optical grating modulation was proposed. Firstly, the complex amplitude of the optical field was modulated by two different directions sinusoidal gratings located at the spatial light modulator. Secondly, relationship between the intensity and the partial derivative of the phase was derivate. Last, the partial derivative of the phase was calculated using intensity images, and then the phase information was recovered. The simulation experiments were carried out to test the recovery ability of the method for simple images, complex images and noisy images. The results show that the proposed method could recover phase information effectively by expediently control the image motion, which applies to the calculation of the phase objects of different scales.

The velocity coupling relationship between the moving platform and the frame deflection was analyzed, optical axis stabilization method was deduced, and aiming at the non-linearity, multi-interference in optical axis stabilization, active disturbance rejection controller based on fuzzy reasoning was proposed to control three axis stabilization systems. Through software simulation and experiment: under1Hz disturbance, with respect to parameter identification method, anti-disturbance isolation degree based on active disturbance rejection controller is increased by 7.4 dB, in the experimental condition of the sweep frequency from 1~2 Hz to 2~4 Hz, the anti-disturbance isolation degree of the fuzzy auto disturbance rejection control method decrease only 2.2 dB. Fuzzy auto disturbance rejection controller has better fast response ,smaller super adjustment and frequency adaptability, also can overcome the platform angular motion and uncertainty disturbance.

An experimental installation using a proto of optical antenna telescope with diameter 150 mm, field of view ±0.17 ° and receive wavelength 974 nm has been built to measure the forward scattering, and the result shows that there are two energy peaks of original-road-returned stray light at 0.35° and 1°. By analysis of these two stray light peaks, a measure to eliminate forward scattered stray light of telescopic system is put forward. By analysis of the influence of primary and secondary lens focal power distribution on stray light of optical antenna, concluded that reduce the focal length of primary mirror can reduce the original-road-returned stray light.

Taken 16 Quadrature Amplitude Modulation (16QAM) as an example, the performance of three kinds of LDPC codes over Galois fields (GF(2m)) for m=1,2,4 in 16QAM systems was analyzed. The simulation results show that 4-ary LDPC code, rather than 16-ary LDPC, shows significant advantages in both error correction performance and decoding efficiency. Then in order to further improve the performance of NB-LDPC codes in high-order modulation systems, the watermark symbols are introducted into 4-ary LDPC codes in 16QAM systems. Compared with traditional non-binary LDPC decoding, the average iteration number of watermark scheme presents a quite obvious decrease, it means that the decoding efficiency can be greatly improved by using watermark scheme. Moreover a further Net Code Gain (NCG) improvement of about 0.1 dB can be attained when bit error ratio BER=10-5.

To extract the edge information of noisy Printed Circuit Board (PCB) defect image, an image edge detection method based on mixed method was proposed. The basic principle and advantages of the image segmentation method based on the Maximum Distance Between Categories (MDBC) were analyzed, and its improved segmentation method (IMDBC) was proposed. The image edge detection method based on the mixed method by combining with median filter, IMDBC, the improved mathematical morphology edge detection operator and LOG operator was discussed. The edge information extraction experiment by using four PCB defect images acquired by CCD and microscope imaging system was carried out. The experiment results show that it can extract better the PCB defect image edge information by using this method, and it has lesser noise points. In this method, the image excellent quality coefficients are from 1.0111 to 1.3586 times of other six methods mentioned in this paper.

The formation pattern of hazy image based on multiple scattering, which is described by atmosphere point spread function (APSF), is modeled. The generalized Gaussian distribution was adopted to approximately formula the expression for APSF through the similarity in the shape and proper convolution operation. Aiming at enhancing the quality with reasonable time consuming, an improved dehazing method was proposed based on dark channel prior (DCP). The approach applies the superpixel algorithm to obtain image patches with similar depth for halo prevention, and based on this, the sky region was also detected more accurately by region merging. Therefore the transmission on the sky and non-sky region was separately estimated, the color distortion reduction in the sky region was achieved. Experimental results show that the proposed method can robustly recover a high-quality haze-free image with abundant details from both subjective and objective image-quality assessment.

In order to study the impact of atmospheric turbulence on the imaging polarization detection of space targets, this paper constructed a simulation analysis model and focused on analyzing detection deviations of degree of linear polarization caused by the atmospheric turbulence. By simulating the time-sharing and simultaneous polarization imaging method, it is found that atmospheric turbulence has obvious influence on the imaging polarimetric measurement accuracy, which impacts the time-sharing imaging polarization method more obviously. And the impact resulting from atmospheric turbulence can be significantly reduced by using the adaptive system to correct partial low order aberrations. For balancing the imaging signal-to-noise ratio and the measurement accuracy of the imaging polarimetry, an improved polarization imaging method which combining with time-sharing and simultaneous imaging method was proposed. The influence of atmospheric turbulence on this method is larger than the simultaneous method slightly. But the proposed method can achieve a better imaging signal-to-noise ratio. Then from simulating and analyzing, it is found that multi-frame images combination method can reduce the deviations of polarimetric measurements under influence of atmospheric turbulence effectively, especially for time-sharing polarization imaging method.

Liquid phase diffusion is a high energy consumption process in chemical production. With the rapid development of the chemical technology based on liquid phase diffusion, especially in some emerging fields such as biomedicine and environmental science, the microcosmic study on the liquid phase diffusion is becoming more and more important. By applying the digital holographic interferometry, a diffusion process in liquid phase of pure ethanol and water was observed. After recording the digital hologram by a Mach-Zehnder interferometer and reconstructing digital hologram of object beam by the gray scale analysis, the phase variation of object wavefront in the diffusion process at different times and the curves of refractive index change in the diffusion area were both acquired. The result shows that by applying the digital holographic interferometry, a fast, real time and high-accuracy diffusion can be realized. Moreover, this method can be used to realize a remote visual monitoring. In addition, this method combining with wavelength and angular multiplexing techniques can be applied to obtain nonlinear characteristics parameters in multiple-phase diffusion measurements.

Residual smile limits the application of Czerny-Turner plane grating spectrometer in the imaging spectrometer. In this paper, different from the traditional method of smile correction based on prism, a method is proposed, which is based on the tilt field mirror. The field curve is corrected, at the same time, the different wavelength slit images in different regions of the field lens are corrected, and the other optical properties of the system are not changed. The Czerny Turner imaging spectrometer slit is 7.8 millimeter length and 0.016 millimeter wide, spectral range from 0.31 to 0.5 microns, spectral resolution 0.4 nanometers, the object focal length 70 millimeters, 1∶1 magnification. Optimization design results, MTF over 0.8, RMS spot radius less than 9 microns, the relative smile less than 0.2%, meet the design requirements. It shows that the method can be used in the systems with weak signal and low transmittance optical glass.

In order to simulate infrared target flying process from far to near distance, a infrared target simulating system was designed, which is composed of high zoom ratio infrared continuous zoom system and large aperture projection system. The zoom ratio of continuous zoom system is 20×, the working wave-band is 8~12 μm. The large-aperture projection system has effective exit aperture of 300mm, and works under environment of -30~40℃. Based on calculation and analysis of system parameters, the material was reasonably selected and the optical power was distributed from the derived achromatic and athermal equations. Finally, the optical passive athermalized design was acquired. With dynamic optics theory, the zoom cam curve was calculated and ploted. The analysis results of system imaging quality show that the image plane is stable during the zoom process, and the imaging quality is good. The system can realize the continuous simulation of high zoom ratio target flying distance, which has advantages of of higher zoom ratio, compact design and good image quality.

For effective emission of superlaser, a kind of monitoring system was designed with precise pointing function. By adjusting the relative position of the primary mirror and the secondary mirror, the focusing system was carried out and could image the target clearly with distance of 100~1000m. ZEMAX software was applied to optimize the optical system, the ZYGO interferometer and the large aperture collimator were served as the auxiliary devices, making the resolution ratio reach 3.38μrad＜5μrad and coaxiality meet the requirements of 4.75″≤5″. The proposed system could capture, identify and track the target, thus leading to precise pointing.

Theeffect of the moving mirror tilt errors on the modulation depth wasanalyzed for the circular aperture in Michelson interferometer. To meet the requirements of interference modulation, the tilt angle of the moving mirror is best controlled within 1″ under the theoretical calculation, corresponding to the phase error within ±6°. In order to solve the key problem, the dynamic alignment system wasused to align the tilt error of the moving mirror ,and make alignment between the moving mirror and the fixed mirror. The experimental results show that the root mean square of phase errors XR and YR is 1.02°and 1.25° respectively by dynamic alignment system to satisfy the systems requirements.It is shown that the dynamic system can effectively align the tilt error of the moving mirror in the longer distance movement process. It is a certain guiding significance to design and develop for the spectrometer with higher resolution.

Influence of the scattering phase function on the diffuse reflection of a micro-region close to the source was investigated by Monte Carlo simulations, and relationship between a semi-empirical model of diffuse reflection and the optical parameters related to the phase function was analyzed. Research shows that the scattered light of the micro-region close to the source is very sensitive to the scattering phase function, and the sensitivity will gradually weaken with increasing of collection aperture φ.When φ>1.8 mm, influence of the scattering phase function on the diffuse reflection is not obvious and relative change in reflectivity is less than 1%; when φ<1.8 mm, influence of the scattering phase function on the diffuse reflection can reach up to 15.2%. When the anisotropic factor g and the second-order optical parameter γ are used to characterize a single-particle scattering properties, the differences of scattering properties are reflected in the third-order parameter δ. The diffuse reflectance decreases with the increasing of δ and the influence of δ on the diffuse reflectance can reach 9%.

A series of Expanded Graphite (EG) with different Expanding Volume (EV) were prepared by the two-step chemical intercalation, and the microstructures and morphologies of the EG particles and their precursors were obtained by X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM) and a stereoscopic microscope, respectively. The extinction behaviour of EG for 1.064 μm laser was measured by a static test, and then the average mass extinction coefficient was calculated and its dependence on EV was obtained and subsequently analyzed by the extinction theory. The results show that EG particles with different EV, especially with an EV of 600 mL·g-1, may be prepared by controlling the synthesis conditions of the precursors, namely graphite intercalation compounds. The average interlayer spacing (d002) of the precursor for EG becomes larger than that of Natural Graphite (NG) due to the two-step intercalation, and the EV of the EG whose precursor’s d002 rises from 0.3590nm up to 0.3711nm, increases from 267 mL·g-1 to 600 mL·g-1. The average mass extinction coefficient of EG depends near-linearly on its EV, and rises from 0.20 m2·g-1 up to 0.48 m2·g-1 while the EV increases from 233 mL·g-1 up to 600 mL·g-1 in the static test. The phenomenon of nonselective scattering occurs when an incident 1.064 μm laser reaches to EG particles, and then the larger is the surface area of an EG particle owing to a higher EV, the stronger is its scattering power to 1.064 μm laser. Meanwhile, much deeper pores and cavities appear with the EV increasing, and may work as equivalent black bodies to improve EG absorption of the incident laser.

A high power linearly polarized Yb fiber laser with picosecond pulse bunch output was designed based on the seed consisting of a gain-switched distributed Bragg reflectorstructured laser diode, which emitted the picosecond pulses with a pulse duration of 200 ps and a repetition rate of 350 MHz. During pre-amplifying, a first-order diffraction transimission acousto-optic modulatorwas used to generate the picosecond pulse bunches, and the repetition rate of the bunches was tunable from 10 kHz to 500 kHz. The picosecond pulse bunch laser was power-amplified using a large mode area polarization maintaining Yb-doped fiber. A high power linearly polarized laser was obtained with an average power of 83 W, a peak power of 12 kW, and an extinction ratio of better than 15 dB. The peak power of 12 kW was obtained under the 100 kHz repetition rate of the pulse bunch, which was composed of 350 sub-pulses. Compared with the conventional continuous wave pulsed lasers, the pulse bunches were able to be obtained by this system, which benefited the further increase of the peak power. This system can be applied to the area of laser micro-machining.

Using a pair of orthogonally linearly polarized beams as the light source, the Soleil-Babinet compensator to offer a continuous phase retardation and a lock-in amplifier as the data collector, a collinear heterodyne interferometer system was presented, which is consisted of a narrow band semiconductor laser with fiber-coupled output and two acousto-optic modulators. The phase characteristics of this system were researched and the influence of the laser beams drift, amplitude modulation and laser line width on the phase measurement was analyzed. The results show that the phase resolution is 0.3611 μm, the phase sensitivity is 27.386°/mm, and the measurement error of this system is 0.090 rad. And this system we proposed can eliminate the affect of the amplitude modulation of acousto-optic modulator and the error caused by laser beam drift. Because the two beams are perfectly collinear, the noise resulting from the environment is also reduced.

A method for characterization of thin-film damage by using laser-induced breakdown spectroscopywas propose. The innate infromation of plasma spectrum when film damaged under the nanosecond pulse laser irradiation was investigated. In experiment, the temperature and electronic density of plasma were seperately 2807.4K and7.4×1017cm-3when the HfO2 film was irradiated by 78mJ laser energy.And whether the film was damaged or not has been identified exactly through identifying the characteristics of the plasma spectrum, which avoid the phenomenon of misjudgement. The results shows that the application of laser-induced breakdown spectroscopy is fully applicable to the measurement of laser damage of the films, and is a highly effective method of test analysis on thin-film laser damage.

A method of simultaneously quantitative measurement of the main elements (Si and Ba) in glass by using Laser-Induced Breakdown Spectroscopy(LIBS) was established. The LIBS system is composed of a Q pulse Nd: YAG laser, an echelle grating spectrometer and an ICCD detector. We collected the LIBS spectra of 4 glass samples. The Boltzmann curves of the main elements Si and Ba were established by using free calibration method. The contents of Si and Ba in glass samples were calculated with Boltzmann curves. The relative error of the contents of Si and Ba ranged from 4.96% to 10.12% and from 4.07% to 9.62%, respectively. The standard deviation of the contents of Si and Ba ranged from 0.38% to 1.29% and from 0.54% to 1.70%, respectively. T test results showed that there was no significant difference between the measured values and the actual values.

A multiple-ring shaped Metal-Insulator-Metal (MIM) plasmonic waveguide with multi-output ports was proposed. From visible lightto nearinfrared wavelengths, the transmission characteristics of the structure were investigated by finite-difference time-domain method. The structure exhibits typical wavelength demultiplexing function, which is due to that the electromagnetic wave energy of different wavelengths can be trapped in different insulator rings and coupled into the corresponding output ports. The resonance theory is employed to analyze the trapping phenomenon.The resonant wavelength of the ring has near linear relationship with the radius and has red shift with increase the value of the filled refractive index. The transmittance of resonant wavelength in the output ports are heavily influenced by the coupled thickness. The proposed multiple-ring shaped MIM waveguide may be useful for plasmonic designs.

A kind of wide-band filter based on guided mode resonance effect was proposed. According to the theory of Rayleigh anomalies, the existence of the phenomenon was proved to have the influence to broaden the bandwidth through calculating the position of the Rayleigh wavelength. The spectrums under the conditions of different structural parameters and materials were obtained based on rigious coulped-wave analysis method. The impact of the parameters on transmittance efficiency and bandwidth could be clearly observed and concluded from the theoretical results.The parameters were chosen as the optimum values for obtaining the best trasmission peak and bandwidth. The center wavelength of the transmission spectrum is 632.8 nm, the peak transmission efficiency is nearly 90% and the bandwidth is 95 nm according to the calculation result.This kind of device has potential prospect in the application of display and image.

A terahertz oscillator based on Smith-Purcell effect was presented. The terahertz oscillator is composed of an electron gun, a modulation cavity, an output cavity and a collector. In the modulation cavity of the novel terahertz oscillator, electron beam was modulated by Smith-Purcell effect. As bunching electron beam passes through output cavity, high-frequency electric field is produced in the gap of output cavity. By the high-frequency electric field, part of the kinetic energy of electron beam can be transformed into the energy of high-frequency field, and the terahertz radiation can be emitted. The simulation results show that when the length of the grating period is 0.6 mm, and energy of electron beam is 100 keV, the terahertz radiation frequency at 349.017 GHz and 346.324 GHz , power spectral density approach 4 kW/GHz, and maximum output peak power over 2 kW can be generated in the terahertz oscillator based on Smith-Purcell effect.

By using Digital Signal Processor (DSP), a digital lock-in amplifier was experimentally demonstrated for extracting 1f and 2f signals in gas detection based on Tunable Diode Laser Absorption Spectroscopy (TDLAS). The orthogonal lock-in amplifying theory was introduced, the algorithm for extracting harmonic signals was designed, and both hardware structure and DSP software were proposed. By using the prepared CH4 samples within the concentration range of 1%~5% and the developed lock-in amplifier, detailed experiments were carried out to derive the device′s performances. As shown by experimental results, the system′s signal-to-noise ratio at the frequency of 2f signal is 34 dB under the CH4 concentration of 5%, which indicates good functions of the lock-in amplifier. The amplitude ratio between 2f and 1f signals is linear to gas concentration. Considering gas preparation and diffusion time, the response time of the detection system is about 96 ~ 98 s. The concentration variation is -92 ppm~+118 ppm for the measured CH4 sample with a concentration of 20000 ppm. The limit of detection obtained from the Allan variance is 29.52 ppm. Compared with analog and commercial lock-in amplifiers, the self-developed device shows great applications in infrared gas detection because of its simple structure, small size, low cost and easy integration.

An electron gun with multiple focus system was designed, and a smaller beam spot was obtained in the computer simulation technology. The different cathode emission models would be actived when different voltage was load on the gird electrode, and which affects the number of electrons emitted from cathode significantly, the number of electrons would increase and decrease under the Schottky emission and Rejecting-field emission mode. When voltage of focusing electrodes is U1∶U2∶U3∶U4∶U5=5∶8∶15∶70∶100, the spot size of 160 mm at the distance of 10 m was acquired in the electron gun model.

Fruit fly Optimization Algorithm（FOA） and Radial-based Function(RBF） neural network model was proposed for evaluating the reliability of white Light Emitting Diode(LED) chip. The failure factors of white LED such as junction temperature, color coordinate shift were selected to the neural network input. Using fruit fly algorithm to optimization RBF neural network in order to improve the precision of the output. Studies have shown that RBF neural network is successfully predicted the LED reliability decay trend, with high stability and robustness, using fruit fly algorithm to predict average error successfully reduced to 3.1%, benefit to set up reliability prediction model in the future.

A kind of space thermal-ion imaging detector was investigated, which can be used in detecting a variety oftargetsource such as thermion, ultraviolet, X-rays etc. The output of the detector is a grayscale image of the target source, the detail information including the gradation level and gradation distribution of the image are obtained based on the intensity and thermal-ion uniformity of the target source. This paper conducted experiments to test the detector with target source of ultraviolet light.Performance parameters as follows have been detected; the resolution is better than 120 μm; the input-output linearity error is <±4% and the output uniformity is better than 97%.

In order to get the quantitative relationship between Cs adsorption and cathode electron affinity variation, GaN photocathode was activated with Cs using the experimental system for activating and evaluating NEA photocathode. According to the theory of semiconductor photoemission and the double dipole layer model, the electron affinity changes with the Cs coverage degree, the function relation between electron affinity and Cs coverage degree were gotten. Cs adsorption mechanism was analyzed, the relationship between the Cs adsorption course and the decrease of effective electron affinity was gotten. The experiment results show: during the course of activation with Cs for negative electron affinity GaN photocathode material, the photocurrent increases from the background value to the maximum according to Cs coverage degree. The position of low kinetic energy cutoff in the electron energy distribution curve is decided by Cs coverage degree during the activation process. When Cs coverage degree varies from 0, 1/2, 2/3 to 1 monolayer, the position of low kinetic energy cutoff shifts to the left in turn. The position of low kinetic energy cutoff will shift to the left about 3eV when Cs coverage degree increases from 0 to 1 monolayer. The reason of the left shifting is the quantity increase of the dipole ［GaN(Mg):Cs］ that help the electrons to escape into the vacuum. The quantity increase of the dipole results in the decrease of vacuum energy level of the surface.

For achieving an optimized efficiency of nanowire array based solar cells, a GaAs axial pin nanowire array solar cell was designed and analyzed through simulation. The optical absorptance of GaAs nanowire was calculated using three-dimensional finite difference time domain simulations. The structure parameters of the nanowire array, such as diameter and density, were optimized, and the optimized absorptance is 87.4%. Then the electrical performance of the solar cell was analyzed by Sentaurus Device electrical simulation module. At last, the structure of the axial pin structure was also optimized according to the optical generation profile, and the final conversion efficiency of the solar cell can reach 17.6% in the optimized structure. The results indicate that the performance of the solar cell can be significantly improved through surface passivation treatment, which can reduce the surface recombination velocity of GaAs nanowires. And through decreasing the volume of the highly doped top region of the nanowire, the carrier recombination can be reduced and thus the efficiency can be enhanced. The analysis can prove some guidance for fabricating high-performance nanowire solar cells.