By using three atmospheric turbulence power spectrum models, namely Kolmogorov spectrum、 modified Hill spectrum and improved Rytov model, we obtain the relationship between scintillation index and atmospheric refractive index structure constant on detection path of residual turbulent scintillation lidar. Changes of turbulence intensity under difference inner scales are analyzed and compared with the situation that not considering the inner scale. The influence of inner scale on the detection of turbulence by residual turbulent scintillation lidar is analyzed according to experimental data. The results show that, in the range of inner scale, by using the modified Hill spectrum, the ratio of refractive index structure constant of the infinite inner scale to refractive index structure constant of not considering the inner scale is 9 in theory, and deviations are 0.4/0.1 orders in experiment at propagation distance of 1020 m and 2040 m, respectively. When we use the improved Rytov model, the ratio of refractive index structure constant of the infinite inner scale to refractive index structure constant of not considering the inner scale is 6, and deviations are 0.6/0.3 orders in experiment at propagation distance of 1024 m and 2040 m, respectively. Theoretical and experimental results show that, to some extent, the refractive index structure constant of the infinite inner scale is deviated from the situation of not considering the inner scale, which is related to propagation distance and the magnitude of inner scale. Therefore, inner scale must be considered in the detection of residual turbulent scintillation lidar.

The coherent structure characteristics of atmospheric turbulence are investigated based on frequency domain wavelet analysis method. The data of wind velocity fluctuation over the ground are analyzed with Mexican Hat wavelet function. According to the maximum energy principle, the principal scale of coherent structure is identified and the coherent structure waveform is extracted by reconstruction formula. Results show that the reconstructed coherent waveform is a signal with quasi-periodic motion, which reflects a middle scale movement of the existing original pulse signal, and their waveforms coincide well with each other in the changing trend. Time and scale maps of wavelet coefficients can well explain the multi-scale and intermittence characteristics of turbulence, and reflect the evolution of turbulence coherent structure. During the analysis period, statistical analysis on the main scale of wind speed coherent structure is carried out, and it’s found that the main scale of coherent structure satisfies the normal distribution approximately.

To represent the polarized reflectance properties of ground-feature’s background, we present a six-component polarized bidirectional reflectance distribution function (pBRDF) model that takes specular reflection, volume scattering and backscattering into account. The model uses the Kubelka-Munk(KM) theory to simulate the volume scattering component, and introduces a backscattering component of Gaussian distribution, which improves the traditional pBRDF model, and makes the new six-component pBRDF model more suitable to the polarized reflectance properties of ground-feature’s background. The polarized spectra of grass and soil under the different observation geometries are obtained based on the theory of multi-angular polarization detection. The variation of the polarized spectral reflectance is also analyzed. The simulated polarization values from the six-component model are compared with the measured data. It is shown that a good agreement is obtained between polarization measurement data and simulated results. The accuracy and validity of model are confirmed.

In order to solve the accurate test problem of encoder angle error with limited angle , the angle error of encoder is tested by plane mirror-autocollimation theodolite. The mathematical model of the relationship between the angle error, the pose dislocation parameters, the angle of encoder and the value of the theodolite is established, the system error of the encoder angle can be corrected by calculating the pose dislocation parameters. The experimental results show that the angle error introduced by the pose dislocation increases monotonically with the increase of encoder angle when the angle range is 0°~40°, the maximum angle error is 742.9". The corrected angle error is basically the same as the angle error without encoder pose dislocation, the maximum angle errors are 4.4" and 3.5", respectively. Encoder angle error with limited angle that cannot be accurately adjusted or does not have a leveling condition can be effectively evaluated by this method.

The advantages of the optical fiber array point source generator relative to the lens array point source generator are analyzed. An optical path difference detection method based on Mach-Zehnder all-fiber interferometer and excess fraction method is proposed, which can measure the optical path difference of all beams relative to the beam emitted from central fiber. Meanwhile, the measurement influence of optical path difference on surface deviation calculation can be eliminated with introducing it into the mathematical model of tilted-wave-interferometry system. The results show that the measurement uncertainty of this detection system is 0.07λ3(λ3=632.8 nm). A parabolic mirror is measured with fiber array based tilted-wave-interferometry system and ZYGO interferometer, and the surface deviations obtained by the two interferometers are consistent.

Based on the mid-infrared quantum cascade laser (QCL) and wavelength-modulation frequency-division multiplexing spectroscopic technique, the simultaneous and high-sensitive NO2 and NH3 concentration measurements are realized. The QCLs with central frequencies around 1600.0 cm-1 and 1103.4 cm-1 are modulated at different frequencies. With the digital lock-in technique, the second harmonic signals are obtained by demodulating the original signals at different frequencies. A measurement system with a 60 m open-path multi-pass cell is developed for simultaneous monitoring of NO2 and NH3 in the air. A 25-cm-long reference gas cell is used to calibrate the system and it is found that the excellent linear response of the system occurs within a wide range of concentration. The detection limits for two kinds of gases are smaller than 10-9. The real-time gas monitoring during 24 h is performed with this system and the measurement results show a good agreement with those given by the reference instruments.

A high-speed modulation of 4×15 Gbit/s 850 nm vertical cavity surface emitting lasers (VCSEL) array with oxidation aperture of 7 μm and adjacent unit interval of 250 μm is demonstrated. Its epitaxy structure has a strained multiple quantum well active region of InGaAs/AlGaAs and a double oxide confinement layer grown with the metal organic chemical vapor deposition (MOCVD) apparatus. And in the chip fabrication process, a series of technologies are used, such as the breakpoint monitor inductively coupled plasma etching and the wet oxidation precise control. The static and dynamic characteristics of the VCSEL array are measured. For the single VCSEL cell, the threshold current and slop efficiency are 0.7 mA and 0.8 W/A, respectively. And the optical power reaches 4.5 mW at the working current of 6 mA, meanwhile the voltage is 2.3 V. Modulated by a 15 Gbit/s non-return zero code (NRZ), VCSEL cells perform eye diagrams with clear profiles, fine stitches, tiny jitter and few crosstalk. For the eye diagram relative parameters, such as rise time, fall time, signal-to-noise ratio, root mean square jitter and so on, some comparisons are made among VCSEL cells in the array. The results indicate that the consistency of the dynamic characteristics is good. In addition, the consistency of device static characteristics among the VCSEL cells in the whole wafer is analyzed through the method of boxplot. All characteristics show a high consistency, which can meet the requirement of mass-production.

In this paper, partial P branch lines in the ν1+ ν3 absorption band of the acetylene are measured by the adaptive dual-comb spectroscopy sampling technique. The validity of the method is verified by comparison of the measured results with the standard absorption lines in HITRAN database. The mechanism of adaptive sampling technique based on the sampling theorem is analyzed. High-order features and bandwidth characteristics of the adaptive sampling techniques are further discussed. In the experiment setup, 200 nm super continuums are generated in nonlinear fiber, and then the wide spectra are extended. Partial absorption lines of the acetylene are retrieved from a 600 μs pulse signal in time domain with 1.09 GHz spectral resolution at a refresh rate of 180 Hz. The fast instabilities between combs are well compensated by the adaptive sampling technique under a room temperature environment. Meanwhile, with a 7.01 MHz stabilization accuracy of repetition rates, we suppress slow drifts effectively by further stabilizing the repetition rates of combs and tuning the center frequency of continuous-wave lasers. In this way, the stable running time of the dual-comb adaptive sampling system is increased from only a few minutes to more than half an hour, and thus the long-term stability and practicability of adaptive dual-comb spectroscopy are enhanced.

The correction ability of dynamic phase error in coherent beam combination for multi-channel large solid laser device is analyzed by stochastic parallel gradient descent (SPGD) algorithm. The fundamental theory of coherent beam combination by SPGD algorithm is introduced. The algorithm is optimized by numerical simulation method. Coherent beam combination of two beams with the wavelength of 800 nm and the bandwidth of 30 fs is experimentally achieved and the performances of SPGD algorithm under the 10, 15, 20, 25 Hz dynamic phase error conditions are tested. Moreover, the processes of dynamic piston and point phase error correction are simulated. The influence of phase noises with different intensities and frequencies on the correction ability is analyzed. The relationships among the control bandwidth, number of beams and iteration rate are computed. The results show that the quadratic sum of far-field intensity is the optimal performance evaluation function of coherent beam combination for high-power short-pulse laser. The adaptive gain can guarantee the stability and improve the convergence speed of the algorithm. The effective control bandwidth decreases with increasing intensity or frequency of phase noise, and increases with increasing iteration rate and decreasing of beam number. Limited by the performance of device,SPGD algorithm cannot be applied to the coherent beam combination for more than four beams laser array with the bandwidth of 30 fs.

Aiming at the three-dimensional inversion problem of high power laser multi-pass amplification, we propose two inversion methods. The first method is a modified gain iterative algorithm based on the curve fitting method of input-output integral energy. The second method is a forward iterative algorithm based on the modified input pulse. In the four-pass amplification with gain distribution, the two methods are verified by numerical simulation. The results show that the two iterative algorithms are effective and feasible, and the three-dimensional intensity distribution of spatio-temporal separation of input pulse can be obtained. The calculated output pulse is basically the same as the demanded value. The relative deviation of the output energy is less than 10-7. The relative deviation of the power waveform obtained by the first method is less than 1%, and this value is less than 10-6 for the second method. The spatio-temporal evolution distortion caused by the saturation effect is solved. The first method relies mainly on the consistency of the forward and inverse model, which is relatively straightforward. The second iterative algorithm introduces a feedback factor, and has high precision and strong expansibility.

The change of temperature rise caused by 1064 nm long-pulse laser irradiation on Si avalanche photodiode (Si-APD) is studied theoretically and experimentally. Considering the Si-APD multilayer structure, we establish a two-dimensional axisymmetric heat conduction model, and simulations under different conditions are carried out. We carry out the experimental study on temperature rise of Si-APD irradiated by long-pulse laser. The simulation results are consistent with the experimental results, which shows that the temperature rise caused by the interaction between long-pulse laser and Si-APD is determined by the energy density and pulse width of incident laser.

Based on the characteristics of scanning beam interference lithography (SBIL), the dynamic exposure model is established for the standing wave effect of the exposure in the photoresist layer. Based on the fast marching method, the development model is established and the evolution rule of grating mask grooves is obtained. In order to reduce the influence of the standing wave effect, a design method for the optimal thickness of anti-reflective coatings (ARCs) is proposed. The simulation results show that the established exposure and development models can effectively predict the groove profile of the grating masks, and optimize the thickness of ARCs simultaneously.

In our previous work, the surface thermal distortion and far-field beam quality of 960-line spectral beam combining grating, which is irradiated by laser with different power densities, are studied by experiment and theory. The conclusion is that the thermal expansion of the substrate is the main cause of the distortion of the grating surface and the decrease of the beam quality. However, the improvement of grating surface heat deposition and the far-field beam quality are not considered. In this paper, the surface temperature, thermal distortion of grating and far-field beam quality at different irradiation power densities are analyzed with the improved model. The influences of the substrate thickness on the temperature, thermal distortion and far-field beam quality of the spectral beam combining grating are also calculated and analyzed. The conclusion is that the increase of substrate thickness can improve the power tolerance of beam combining gratings and the far-field beam quality of diffraction spots.

Soft X-ray spectrographs based on flat-field diffraction gratings play important roles in the fields of laser plasma diagnostics, etc. The flat-field gratings fabricated by electron beam lithography-near field holography (EBL-NFH) integrate the advantages of both sides, including the flexibility and high accuracy of spatial distribution of groove density due to EBL, and low stray light and low high-order harmonics similar to those of holographic gratings. This paper simulates the effect of dominating fabrication errors during EBL and NFH on the spectral images of flat-field gratings based on ray tracing theory. The results indicate that the fabrication errors of EBL and NFH will broaden spectral lines and degrade spectral images. We take a typical soft X-ray flat-field grating with a central density of 2400 lines/mm ranging from 0.8 nm to 6.0 nm as an example, when the length of the fused silica mask is 50 mm (along the direction of grating vector), the segment number should not be less than 1500. And the broadening of spectral lines due to the groove density error of the fused silica mask during EBL can be compensated by adjusting the parameters of NFH, such as the spacing and angle between the fused silica mask and the photoresist-coated grating substrate. The dominating factors are spacing and angle between the fused silica mask and the photoresist-coated grating substrate. And during NFH, rather than removing every fabrication parameter errors, the spectral line broadening can be eliminated by optimizing relative values among different errors. The simulation results are helpful to optimize the EBL-writing strategy for the mask, reduce the complexity of mask fabrication, and design and adjust the light path of NFH.

The LED caustic beam is generated by LED light source. A method of using cross-spectral density function and superposition of multi-spectral is proposed to calculate the intensity distribution of the LED caustic beam through the axicon. The influence of parameters such as dispersion on caustic beam is theoretically and experimentally demonstrated. The influence of the transmission distance on the LED caustic beam is further studied. It is found that the outer contour of the caustic beam becomes larger and the central light spots symmetrically split into light spot array as the transmission distance increases. Meanwhile, the central intensity decreases correspondingly, and the contrast of the light spot array decreases gradually. It will evolve into an approximately hollow beam eventually. This research results enrich the connotation of caustic beam, and provide a theoretical basis and experimental evidence for the practical application of LED caustic beam.

An elliptic cylindrical fiber optic gyroscope (FOG) for petroleum well trajectory inertial measurement is designed for the special condition of the limited borehole diameter and the large gradient of temperature in inclinometer while drilling (IWD). Due to the thermally induced nonreciprocal phase shift in fiber coil, the three-dimensional (3D) temperature transient response mathematical model of elliptic cylindrical fiber coil is established by quadrupole (QAD) winding method, which is based on the Shupe effect of fiber coil. Combined with the actual working environment of FOG, we use finite element method to numerically simulate elliptic cylindrical fiber coil and analyze the Shupe error at working temperature gradient quantitatively. The experimental results verify the correctness of the model. In order to compare the thermal error rates of two fiber coils, we simulate the cylindrical and elliptic cylindrical fiber coils under the same temperature excitation when the fiber length, the layers of fiber coil and the radius of fiber coil are fixed. The results show that the thermal error rate of the elliptic cylindrical fiber coil is 35% to 39% smaller than that of cylindrical fiber coil and the precision of the well trajectory inertial measurement can be improved when the underground measuring instrument is limited in volume.

The Doppler frequency shift of the inter-satellite coherent communication system reaches the order of Gigahertz. At the same time, it is affected by the line width and phase noise of the tuning laser, which imposes high requirements on the optical phase-locked loop system. Based on Costas loop technology, an optical locked loop is achieved through inner and outer loops, and the local laser is tuned when the tuning of temperature, piezoelectric ceramics(PZT), and acousto-optic modulation device(AOFS) are compounded together. An experimental test system is set up to test the performance of the loops. It turns out that this system is capable of a phase locked range of 4 GHz and a phase locked bandwidth of 1.7 MHz. Doppler frequency shift between the signal light and the local laser can be tracked, line width of the laser is compensated and the phase is locked quickly with a final residual phase error of 5.1°.

In the developed 28 GHz radio over fiber (RoF) transmission system, an eye diagram of the recovered baseband data changes between opening and closing with time after transmission through an optical fiber, which results in a destruction of the communication reliability. After a detailed experimental investigation and theoretical analysis on this phenomenon, we find the propagation delay of radio frequency (RF) signals changes with the temperature variation of the optical fiber, which can extremely destroy the communication reliability, especially for the RoF system with a high-frequency carrier and a long-distance transmission. In this paper, we propose and experimentally demonstrate an improved RoF system to overcome the phase-shift variation based on the carrier recovery technique. We employ a dual down-conversion structure and extract synchronous clock from the intermediate frequency signal to acquire a stable recovered original baseband data. A low bit error rate ( less than 10-9) is achieved after transmission over a 25 km single mode fiber in this improved 28 GHz RoF system with a data signal of 1 Gb/s.

A hyperspectral imaging method based on dual-channel shearing interferometry is proposed and its signal-to-noise ratio (SNR) is analyzed. The spectral restoration SNR of interferometry spectral imaging system is introduced. The principle of dual-rectangle shearing interferometry and SNR of dual-channel differential detection are discussed and simulated. The experimental apparatus is built, and the SNR contrast experiment of the actual scene target is carried out. The spectral detection SNR of dual-channel differential detection system is obtained, which is compared and analyzed with SNR of non-differential detection system. Results show that the spectral SNR of the proposed differential interferometry hyperspectral imaging system is 2 times as that of the single-channel system.

Robust principle component analysis (RPCA) algorithm is introduced to eliminate the mass speckle noise in optical coherence tomography (OCT) system. We understand the characteristics of speckle noise in OCT system by analyzing the speckle generation mechanism in OCT system. Combining the characteristics of OCT system itself, the low-rank matrix recovered model based on RPCA algorithm is proved to be suitable for the speckle noise reduction in OCT system. The best estimation which decomposes the original image of OCT into speckle noise image and sample cross section image can be obtained based on the RPCA algorithm. RPCA algorithm can retain the speckle patterns of the sample’s own structure while separating the speckle noise, and avoid the generation of the artifact effectively. The result shows that RPCA algorithm can effectively suppress the speckle noise, enhance the signal-to-noise ratio, and improve the effect of OCT images, through comparing the images before and after processing.

In order to improve the robustness of correlation filtering (CF) tracking algorithm, and overcome the problems that the traditional CF method cannot handle target scale change and does not use image color feature, a scale adaptive tracking algorithm is proposed based on correlation filtering improvement with fused color features. Firstly, the target searching area of the image is transferred from the color space of the three primary colors (RGB) to the Lab color space to obtain the Lab three channel features of the search area. Then, Lab color features and histogram of oriented gradients (HOG) feature are fused to obtain the image feature of multi-channel. The kernelized correlation filtering (KCF) is used to get the output response chart and find the position of maximum response, namely target location. Finally, the scale model is established through the Lab color feature, and the different scale image blocks are intercepted from the current frame target position. Optimal estimation of the target scale is obtained when we compare the scale image blocks with scale models. 35 pieces of open color video sequences are selected in experiments for testing, and the proposed method is compared with five other tracking methods with excellent performance. Experimental results show that the proposed method is well adapted to the phenomena of target occlusions, deformation and scale change in color video sequences,and its average performance outperforms the other compared methods. At the same time, the real-time tracking speed of the proposed method is 76 frame·s-1.

In the practical applications for camera pose estimation, the coordinates of reference points inevitably contain measurement errors, and the magnitude of the errors will not always be the same. If the camera pose is estimated directly without distinguishing the errors, the estimation result may be very different from the true value. Therefore, the weighted orthogonal iterative algorithm is proposed based on the widely used orthogonal iterative algorithm. In this algorithm, the weighted collinear error is taken as the objective function. In each iteration, the weight coefficients are determined according to the re-projection errors in image, and the camera pose estimation results are optimized by the coefficients. This algorithm satisfies the conditions of global convergence, and has the advantages of high precision and good robustness. The experimental results show that the proposed algorithm is effective. The estimation results of the proposed algorithm are significantly better than those of the orthogonal iterative algorithm, when the coordinates of reference points contain different errors. It shows that the proposed algorithm has strong engineering practical values.

In order to solve the problems that the similarity target tracking algorithm mainly considers the intraclass similarity of targets and ignores the interclass differences of different targets. A visual tracking algorithm based on classification-validation model is proposed, which adds attribute information to the similarity algorithm. The proposed algorithm constructs the loss function with similarity and class information, and learns intraclass similarity and interclass differences in high dimensional space. The classification and verification module is adopted to update network parameters when the target template and candidate target input into the network model. With the trained network, the deep embedding feature of target and candidate target is extracted, thus, the target tracking is achieved. Experiments are carried out on the OTB50 and UAV123 databases. Results show that the proposed algorithm can improve the tracking effect with increased target information, and has strong robustness to the similar targets.

In order to solve the accuracy problem of pose measurement of space target based on three linear array CCD, we propose a high precision pose calculation method. This algorithm integrates all linear array CCD camera coordinate systems. The improved orthogonal iterative algorithm is used to solve the pose parameters by establishing a new error evaluation function, and the nonlinear optimization is performed subsequently. Simulation and measurement results show that the proposed algorithm effectively avoids the problem of no-convergence or poor convergence caused by data deterioration or initial value selection. Compared with the traditional algorithm, both the measurement accuracy and noise immunity of the proposed algorithm are effectively improved and the computational efficiency is improved by 4.6 times. The maximum relative error of six degree of freedom is 0.71% in actual measurement. The proposed system can realize high precision and real-time measurement of spatial target, which has the advantages of convenient installation and wide applications.

In order to meet the requirements of high coverage rate and high precision in large-size three-dimensional profile measurement, an intelligent network planning method considering the measurement coverage rate and three-dimensional uncertainty is proposed. Combined with the requirements of the visual measurement, the discretization geometry model of visual measurement network is determined, the decision variables of network planning are established, and two concepts of the visual measurement network coverage rate and the three-dimensional uncertainty of the target are also given. The multi-visual network is realized accurately by the analysis of several constraint conditions of camera position and globally searching on decision variables through multi-objective genetic algorithm. Simulation of the propeller main structural model is conducted. It is concluded that the coverage rate of measurement network can reach 99.72%, and the three-dimensional uncertainty can converge to 0.0326 mm. The effectiveness and feasibility of the strategy are verified through single vision multi-station measurement experiment.

To provide a real-time intraoperative feedback and suggest an applied potential to guide stomach cancer surgery for removal of normal tissue as little as possible, we use an optical coherence tomography (OCT) to image normal tissue and tumor tissue of 39 stomach cancerous patients, and compare OCT images and pathological sections. The results show that OCT images of 38 patients show obvious difference between normal tissue and tumor tissue. For the 4 stomach mucinous carcinomas, the mucus secreted by tumor of stomach mucinous carcinoma destroys the layer structure, texture, and mucosa of stomach tissue. The poorer backscattering of mucus and the greater difference between backscattering of mucosal tissue make the OCT images of stomach mucinous carcinoma clearer. The B-mode ultrasonic scanning (B-scan) OCT images can distinguish the boundary of the cancerous tissue and the normal tissue. A volumetric image can be built with B-scan images by the three-dimensional (3D) reconstruction method. The layered section images in tissue-depth direction are obtained after volumetric surface flattening. These images provide another dimensionality to view stomach cancerous boundary. The cross validation with B-scan images can show excellent distinction.

An experimental scheme for realizing open-destination quantum teleportation network is proposed by means of the four-partite entangled states of light. After the joint measurement of the unknown quantum state with a sub-mode of the entangled state light field in the input node, one can recover this unknown state at any other nodes by choosing a transmission direction of classical channels according to the requirement. Through the calculations of the quantum state fidelity in three different transmission directions, it is proved that the quantum teleportation by these three means is all possible and the open transmission is realized.

The novel K6Ba4B8O19∶x%Eu3+ fluorescent powders are prepared by the solid phase reaction method and their fluorescence quantum efficiency is measured. The results indicate that the nearly pure phase of K6Ba4B8O19 matrix is synthesized experimentally. When the synthesis temperature is 750 ℃, the X-ray diffraction spectrum of K6Ba4B8O19∶5%Eu3+ is well consistent with that in the standard card of K6Ba4B8O19. Under an excitation at 395 nm wavelength, the orange and the red emission peaks occur at 592 nm (5D0F1) and 613 nm (5D0F2) of K6Ba4B8O19∶Eu3+, respectively. The fluorescence emission intensity increases with the increase of Eu3+ mole fraction, and reaches the maximum when the mole fraction of Eu3+ is 6%. The fluorescence quantum efficiency of K6Ba4B8O19∶6%Eu3+ under an excitation at 395 nm is 4.51%. The obtained powders are irregularly granular.

Under different sputtering powers, the ZnO∶W film layers are deposited for 55 min by the radio frequency magnetron sputtering method, and then are hydrotreated for 8 minutes by maintaining the stability of sputtering parameters and adding hydrogen with a volume fraction of 5%. The ZnO∶W transparent conductive films with surface-textured structures are obtained. The micro-morphology, structure and surface-texturing degree of samples are tested and analyzed. The results indicate that, the surface-texturing degree of the ZnO∶W samples after hydrogenation for 8 min at the sputtering power of 200 W reaches 92.82, meanwhile, their electro-conductivity is superior whose average electrical resistivity is 3.93×10-3 Ω·cm. It is hopeful for this surface textured structure to further improve the conversion efficiency of the ZnO transparent conductive electrode cells.

Based on the simplified model of fiber laser,the transmission characteristics of bright-dark soliton pair in fiber laser are studied numerically by the split-step Fourier method. The results show that the stable existence of the bright-dark soliton pair is related to the group velocity dispersion, and the bright-dark soliton pair can maintain the stable transmission in the zero dispersion region. At the same time, the bright-dark soliton pair is influenced by the small signal gain coefficient, saturated energy, initial pulse width, and polarization angle in fiber laser. The larger the small signal gain coefficient or the saturation energy,the peak intensity of the bright-dark soliton pair is greater with the width narrower. When the peak intensity increases to a certain degree, the bright-dark soliton pair is split. The polarization controller can control the output of the bright-dark soliton pair. These results can provide some theoretical basis for the research on the generation of signal sources of bright-dark soliton pair in fiber laser.

In order to avoid the influence of the ambient temperature change on the projection image quality of the infrared dual-band target simulator, the integrated optical-structural-thermal analysis of the zoom projection lens of this simulator is conducted. The finite element analysis model of the zoom projection lens is established. By the quasi-static treatment to the unsteady thermal stress, the thermal analysis and the statics analysis are finished. The displacement nephogram of overall unit versus temperature is also obtained. The discrete node coordinate data are converted into the vector deformation data by the finite element data conversion algorithm. The surface thermal deformation of each lens is fitted by the Householder algorithm based on the Zernike polynomials. If the fitting coefficients are imported to the optical design software, the thermal analysis results of the zoom projection lens under different temperatures can be obtained. The results show that the projection image quality is insensitive to the thermal deformation of the overall unit when the temperature is in the range of 10-30 ℃.

The surface description and design methods of annularly piecewise surfaces are proposed. A high-precision transformation method from aspherical surface to annularly piecewise surface is proposed to construct an initial surface, and the optimization strategies, constraints and implementation methods for the annularly piecewise surface are discussed. This proposed surface is employed to design and optimize an ultra-short projection lens. The total length is 155 mm and the maximum distortion is 1.36% after optimization. The research results indicate that this annularly piecewise surface can improve the freedom and flexibility of optical design.

To solve the problem that multi-focus image fusion results in virtual shadow at the target object edge, a multi-focus image fusion algorithm is proposed based on the guided filtering and improved pulse coupled neural network (PCNN). The source image is decomposed by a guided filter with the multi-scale edge-preserving decomposition, and the preliminary fusion, and the obtained basic and detail images are fused preliminarily by different guided filtering weighted fusion strategies. Preliminary fusion image is used as external input excitation to stimulate the improved PCNN model. The source images are according to the fusion weight map to obtain the final fusion image. Experimental results show that, compared with traditional fusion algorithms, the detail information of edge, region boundary and texture of source images are preserved by the proposed algorithm, which avoids virtual shadow at target object edge, and improves fusion image quality.

On the basis of computer simulation technology (CST) software,the polarization characteristics of two-dimensional metal grating arrays in 0.1-10 THz region are numerically analyzed. Different periodic metal copper grating arrays with 20 nm thickness deposited on 500 μm thick high-resistance silicon substrate are experimentally prepared by photo-lithography and thin-film technology. Then, the transmission and reflection characteristics of the structure are measured by Fourier transform spectrometer. Results show that the grating arrays have good polarization characteristics of the transmission and reflection in terahertz broad-band,and the polarization range can be adjusted by the structural period. Our results provide a reference for the further study and application of THz polarizer.

The photonic crystal filter and optical switch are designed based on the garnet-type ferrite magnetic material. The band structure of the photonic crystal with a specific radius is analyzed by the plane wave expansion method (PWM), and the change of coupling frequency of magnetic materials with the magnetic field is analyzed by the finite-difference time-domain (FDTD) method. The results show that, when the magnetic field is not added, this device has excellent frequency selection and filtering functions, the transmissivity of each target light signal is above 90% and the channel crosstalk is small. After the addition of the magnetic field, the coupling frequency of the coupling cavity changes and the device is in a closed state. The maximum stable closing time of this device is 26.4 ps and the maximum transmissivity is only 8%, which indicates that the cut-off effect is obvious and it possesses a good switching characteristic.

A composite waveguide modulator based on graphene is proposed and the rigid three-dimensional numerical simulation results demonstrate the working states of this modulator. The surface plasmon polaritons in the slits of this modulator are used to strongly confine the electromagnetic wave, which enhances the interaction between the light and the graphene and thus improves the modulation performance of this modulator. Its modulation efficiency can reach 0.197 dB·μm-1. The on-off keying modulation with a modulation depth of 3 dB can be achieved when the modulator length is 15 μm. Meanwhile, the insertion loss is 0.4 dB and the modulation bandwidth is 1.85 GHz. The coupler connecting the input waveguide is designed, and the coupling efficiency can reach 86.6% when the coupler length is just 1 μm.

The localized surface plasmon resonance (LSPR) response of single core-capped non-spherically-symmetric nanoparticles with different structural parameters is calculated based on the three-dimensional finite-difference time-domain method. The SiO2@Au core-capped nanoparticles are prepared by the template method and the vacuum evaporation technique. The surface morphologies and optical properties are measured and analyzed by the transmission electron microscopy and the UV-visible near-infrared spectrophotometer. The effects of structural parameters such as metal shell thickness, core-shell ratio, core diameter and metal surface coverage on the LSPR peak absorption wavelength and absorption cross section are obtained. The results indicate that a small change of the structural parameters of core-capped nanoparticles results in a broadband red shift of the LSPR peak in the visible to near infrared spectral range.

In order to simplify the structure of the active frequency selective surface (FSS) and improve the control performance of its resonant frequency, we propose an optically controlled active FSS that uses the photoconductive properties of the photoconductive thin film to change the structure size of the FSS. The relationship between the structure size of FSS and the center resonant frequency is elaborated in theory. Taking the optically controlled active FSS of cross dipole slot-element as an example, the center resonance frequency is changed from 23 GHz (before illumination) to 28 GHz (after illumination)by software CST simulation. The optically controlled active FSS structure is fabricated by coating, electron beam evaporation and photolithography. The influence of the doping amount, annealing temperature, annealing time, light frequency and light power on the photoelectric properties of the photoconductive thin films is analyzed. The results show that the sensitivity wavelength changes with the molecular number ratio of CdS and CdSe (1∶1~5∶1); the molar molecular number of CdCl2、InCl3 and CuCl2 could change the ratio of bright square resistance and dark square resistance, and the effect is best when the molecular number ratio is 3.6∶2.6∶1.3; with annealing temperature of 750 ℃ and annealing time of 30 s, the photoelectric characteristics and ohmic contact of photoconductive thin film reach peak. The test results show that the center resonance frequency of optically controlled active FSS is changed from 23.8 GHz to 28 GHz before and after illumination in the conditions of 200 mW/cm2 light power and 0.6 μm light wavelength, which is consistent with the simulation results.

Modulation transfer function (MTF) value is an important parameter to characterize the imaging performance of mercury cadmium telluride (HgCdTe) infrared detector. Crosstalk is one of the major factors which degrade the MTF value of detector. The reasonable device structure design can effectively suppress crosstalk and improve the MTF value of the device. A HgCdTe infrared focal plane detector with metal frame structure is proposed, which can effectively absorb laterally diffused photo-carriers and suppress crosstalk. We also carry out measurement and analysis of the MTF of the detectors with and without metal frame structure. The experimental results indicate that, compared with the detector without metal frame structure, the detector with metal frame structure can effectively increase MTF value of detector.

The structural features and the energy deposition process of γ-ray photons in the pixels for the 4 transistors pinned photodiode active pixel sensors (4T-PPD-APSs) are analyzed. By the establishment of simulation calculation models of sensor pixels and pixel array and by the experiment of γ-ray radiation response, the response characteristics of the active pixel sensors (APS) under different photon energies and different radioactivity level conditions are investigated. The research results show that, the energy deposition of the γ photon at the photodiode spatial charge area and the formation of diffused photocurrent are the root causes for the photon response phenomena occurring in the APS. The mean pixel value first increases and then tends to saturate with the increase of the dose rate. When the multiple peaks appear in the typical event areas, the statistical pixel value cannot accurately reflect the radioactivity level of the radiation fields.

Aiming at the problem of the ship detection with a low accuracy in the offshore and inland river scenes, a method based on shortwave infrared multispectral remote sensing images is proposed to realize water segmentation and automatic detection of ship. Based on the low reflectance characteristic of water area in the shortwave infrared frequency range, the water area is rapidly and accurately extracted from the images by using the threshold segmentation and morphological processing. Then, the image chips of candidate targets are extracted by using the visual saliency model for searching the targets in the water areas. As for the possible existence of phony targets, the gray-scale distribution histogram is proposed to describe the characteristics of gray-scale distribution of the target chips, which are combined with the gradient direction information to eliminate phony targets by the method of threshold constraint. The results show that the proposed method can efficiently detect the ship targets with different sizes in offshore and inland rivers. 279 candidate targets are obtained after the saliency detection and 138 of 142 true targets are detected after the target discrimination step. The false discovery rate is less than 6% and the recall rate is higher than 97%.

The multi-channel wide-swath synthetic aperture imaging ladar (SAIL) transceiver system is researched. A method to realize the far-field instantaneous wide-swath imaging is presented. The structure of multi-channel wide-swath SAIL transceiver system is analyzed. In particular, the transmitter device is studied and the characteristics of the layout of fibers in the fiber array device are analyzed. The tilt layout of the fibers is given. After that, we further optimize the fiber layout in the fiber array device. The layout model of the fibers for the multi-channel wide-swath SAIL launcher is established, the best layout of the fibers is given. Finally, the structure of the array detectors in the multi-channel wide-swath SAIL receiver is given. This will be of vital significance for the long-distance high-resolution wide-swath airborne SAIL.

The equivalent relationship between the spaceborne synthetic aperture radar strict geometry imaging model and the rational polynomial model is derived. By modeling the error propagation characteristics of the whole link, we simulate and evaluate the quantitative relationship among positioning accuracy, image source angle and corresponding point matching accuracy. The theoretical accuracy which heterogeneous stereoscopic positioning can achieve and its superiority are analyzed, and a set of explicit data selection strategies is derived. Correctness of the proposed theory is fully verified by the in-orbit data test, and the error rules under different data combinations are analyzed in detail, which provides a reliable basis for the practical applications of heterogeneous stereoscopic positioning.

Reflected point light source equipment can be applied to on-orbit modulation transfer function detection and absolute radiometric calibration of optical remote sensors. Its high-precision pointing is the key to ensure the sunlight reflect to the entrance pupil of remote sensors, and the improvement of pointing accuracy can reduce the size and weight of current point light source, which has great importance in practice. A geometric error calibration model and a reflector normal calibration model are established, and the dependence among parameters of the rotation matrix is eliminated. Damping Gauss-Newton method is applied to iteratively solve the model parameters. A pointing accuracy better than 0.1° for reflected point light source is obtained. The study will lay the foundation for high accuracy, high frequency, and full dynamic range calibration of optical satellite remote sensors.

The special seasonal glint phenomenon of solar arrays is caused by the special position kept by the three-axis stabilization geosynchronous earth orbit (GEO) satellite and the motion law of the solar arrays. Quantitative analysis about the theory of the phenomenon is made based on the bidirectional reflectance distribution function of the solar arrays materials and the sun movement in Earth centered coordinate. The characteristics of glint phenomenon are summed up and the conclusions are validated by simulation tests. The results indicate that, for any telescope on the ground, there are two durations one year to detect the glint phenomenon of solar arrays,in which each duration lasts about 21 days, and the detect time one day is about 32 minutes for each GEO satellites. The conclusions could not only provide references to detect GEO satellites, but also could be the basis to analyze the working state and motion state of GEO satellites.

A tapered fiber is prepared with a simple chemical etching method, and modified with Ag nanoparticles (AgNPs) by solution chemical deposition method to prepare the tapered fiber surface-enhanced Raman scattering (SERS) probe. The preparation process is optimized by the change of key parameters, such as reaction temperature, deposition time and the concentration of silver nitrate solution. The Raman measurement experiments of the fiber SERS probes under different preparation process conditions are completed. The results indicate that the best Raman measurement performance of the tapered fiber SERS probe can be acquired at room temperature, when the deposition time is 120 s, the concentration of silver nitrate solution is 0.1 mol/L, and the optimal enhancement factor is about 1010. In addition, corresponding to ten samples with different sizes of AgNPs and the coverage areas, we adopt FDTD Solutions to calculate the enhancement factor and obtain theoretical Raman enhancement factor of 107-108.

Transparent crystal luminescence at impact loading is closely related to its microscopic damage and structure change. The multichannel radiation pyrometer with light-gas gun and spontaneous spectroscopic system are combined to study the light emission of shocked sapphire. The light spectrum of sapphire range is obtained in 400-800 nm wavelength. The spectral distribution exhibits typical thermal radiation characteristics. The radiation temperature is in agreement with the corresponding melting temperature. The mechanism of the luminescence of the sapphire shear band is studied in combination with the radiation temperature and the spectral distribution.

Based on diode laser wavelength modulation spectroscopy technique, a set of real-time and on-line measurement system for trace gases is established with active control parameters. In order to improve the performance of real-time and on-line measurement and the detection precision of the system, after a theoretical simulation of the effects of temperature and pressure on the measurement concentration, we actively control the temperature, pressure and mass flow of gas, and they can keep long-term stability. Moreover, the digitized techniques of wavelet denoising and Kalman filtering are jointly applied to the system. CO2 molecular absorption experimental results show that the signal-to-noise ratio of the absorption spectrum is improved by about 30% with the application of wavelet denoising, and the application of Kalman filter improves the measurement precision of concentration from 2.5×10-7 to 7×10-8. The stable time of the system given by Allan variance is about 60 s. The results obtained by measuring the concentration of CO2 in laboratory indicate that the system has good stability and reliability, and it can monitor the concentration change of trace gas very well.

Spectral images contain abundant space information and spectral information, which can provide important information support for space-based early warning detection. However, the huge amounts of data also brings great challenge for hardware. The traditional treatment of first sampling and then compressing based on Nyquist sampling not only can’t solve the problem of mass-data fundamentally, but also causes wasting of sources. To solve this problem, we propose a spectral imaging and reconstruction method based on spatial compressive sampling and spectral Karhunen-Loève (KL) transform by using the sparsity of single-band images and the spectral redundant of spatial encoded data. A two-dimensional composite regular reconstruction model based on1-norm and total variation is constructed for single band images, and an inference algorithm named two-dimensional compound regularized projection gradient (2D-CRPG) is then proposed for the model by combining the projection gradient method with the soft-threshold operator. The results show that the spectral imaging and reconstruction method based on spatial compressive sampling and KL transform can effectively reduce the cost of data sampling, and thus can benefit the spectral imaging of space-based early warning detection. The 2D-CRPG reconstruction algorithm can effectively preserve structural information of spectral images, thus the original spectral image can be reconstructed at a limited sampling rate.

The national standard of pulse waveform parameter based on the NTN technique cannot fully meet the measurement and calibration requirements of the current ultra-high speed electrical pulse waveform. We structure the pulse waveform measurement system based on electro-optic sampling technique and independently design and prepare the high frequency LiTaO3-based electro-optic modulator with coplanar waveguide structure. The 3 dB frequency of the modulator measured by the network analysis system can reach 100 GHz. We optimize the system parameters by analyzing the experimental results of the output pulse waveform of photodetector. On the basis of the above optimization and improvement, we finally achieve the precise measurement for the electric pulse waveform of 70 GHz high-speed photodetector, and the rise time and full width at half maximum of the measured waveform are 4.6 ps and 5.0 ps, respectively. It will give reference for the establishment and sustained promotion of the national standard pulse waveform parameters of our country based on the electro-optic sampling technique.