The calculation accuracy of atmospheric radiative transfer depends greatly on the precision of atmospheric parameters. The establishment of a local atmospheric parameter model plays an important role in the calculation of atmospheric radiative transfer for the photoelectric engineering. By using the data of currently available, including balloon-sounding data, satellite observation data, and some surface observation data at different areas in China, a preliminary model of atmospheric parameters was established, including the daily average, monthly average and yearly average profiles from the ground to 120 km of atmospheric temperature, humidity, air pressure, and density, as well as the monthly average of the ground visibility, covering the 91 observing stations in China. These parameters were integrated in the Combined Atmospheric Radiative Transfer calculation software (CART) to calculate atmospheric transmittance and atmospheric background radiation. The spatial distribution of atmospheric parameters of 5 stations and the monthly distribution of atmospheric thermal background radiation and its geographical distribution in China were shown in the paper.

The actual effect of laser propagation in the atmosphere is not only related to its own propagation mechanism, but also closely related to atmospheric factors. Therefore, to accurately evaluate the effect of laser atmospheric propagation, it is not only necessary to carry out the mechanism research and establish the mathematical model of laser atmosoheric propagation, but also mecessary to carry out measurement, analysis and prediction of the optical characteristics of the atmosphere in the propagating process. Considering the complexity of the real atmospheric environment and the interaction of many factors, most of the researches adopt the physical experiment or the numerical simulation with controlled parameters to quantitatively reveal the influence of various atmospheric factors on laser propagation. Based on a large number of field measurements and the physical correlation analysis, the research of atmospheric optical characteristics focuses on the parametric modeling of optical turbulence. The development of the performance evaluation technology for the high energy laser was briefly introduced when propagating in the atmosphere at home and aboard, and its development trend for the practical application of high energy laser system in the future was pointed out.

Quantitative identification of cloud is very important in meteorological satellite data retrieval, and the result of cloud detection affects the accuracy directly. In fact, the cloud detecting technology is actually a process of distinguishing the objects and background, and the purpose of detection is to extract cloud features. Therefore, much signals processing and system algorithms have been applied to the technology of cloud detection. The matching pursuit algorithm (MP) is a very effective algorithm for feature extraction, which is developed in recent years, and the Orthogonal Matching Pursuit algorithm (OMP) can improve the signal-to-noise ratio more effectively. In this paper, Orthogonal Matching Pursuit algorithm and multi-channel threshold method were combined to carry out relevant research on cloud detection of MODIS data. Based on the MODIS cloud detection results, it could be proved that the integrative algorithm of multi-channel threshold combined with the Orthogonal Matching Pursuit algorithm would be more effective to cloud detection.

The total atmospheric transmittance is an important parameter reflecting the optical properties of the atmosphere. In the fields of atmospheric radiation, remote sensing, air quality monitoring and opto-electronic engineering, it is necessary to make a deep study on the atmospheric transmittance. In this paper, the methods of acquiring atmospheric transmittance were discussed in detail, and the latest progress and related problems of different acquisition methods were analyzed. The characteristics of software based simulation and direct measurement were compared and analyzed, and at the last, the future research was also prospected.

The scattering phase function is an important parameter for studying the optical transmission characteristics in aerosols. Four approximate scattering phase functions commonly used in Monte Carlo simulations in atmospheric radiation propagation were compared. Aiming at the problem that the parameters of the Two-Term Henyey-Greenstein (TTHG) phase function were difficult to determine, a TTHG scattering phase function based on particle swarm optimization was proposed. This function can well fit the Mie scattering phase function, especially at backscatter angles greater than 90°. Compared with the phase functions such as HG, HG* and RHG, the phase function proposed in this paper can better approximate the actual scattering and obtain more accurate Monte Carlo simulation results.

The atmospheric infrared radiance was measured at Ali, Delingha and Huairou observing station using a self-made measurement system in the infrared M′(4.605-4.755 μm) band. Based on the blackbody calibration and the radiative transfer equation, a simplified relation between the effective output value, the average zenith atmospheric transmissivity and the zenith angles can be obtained. Atmospheric infrared radiation of different zenith angles at three Astronomical Station were measured and scanned, and the above formula was used to fit the average atmospheric transmissivity of the M′band. The measurement results show that the weighted average values of the atmospheric transmissivity in the three places are 0.805, 0.758 and 0.650 respectively, with the fluctuations of 0.081, 0.250, and 0.073 respectively. The average transmissivity simulated by MODTRAN software was respectively 0.851, 0.805, 0.615, which was close to the results from the measurement. The error analysis shows that the propagation error decreases with the increasing effective output value. The theoretical error of indirect measurement method was analyzed to be less than 10%. This paper provided a on-site and real-time measuring method of the atmospheric infrared transmissivity independent of meteorological data.

Aiming at the problem that remote sensing data of detection band of infrared early warning satellite(IEWS) is difficult to obtain, the earth background radiation simulation method of IEWS detection waveband based on retrieving earth surface temperature was studied. The earth surface temperature distribution maps were generated by using a generalized single-channel algorithm for retrieving earth surface temperature of the FY-3/MERSI datasets. On this basis, the earth infrared radiation model was constructed, which fully considered the influence of altitude, atmospheric model, surface type and other factors on earth surface radiation. The joint programming of MATLAB and MODTRAN was used to calculate the surface radiation corresponding to each pixel, and realize the generation of earth background radiation image of IEWS detection band. The simulation results show that the simulated images have high resolution, and can accurately reflect the earth background radiation characteristics of IEWS detection waveband. The research result provides scene data support for studying IEWS operational effectiveness evaluation and target recognition technology.

In order to implement measurement of the close wind field accurate and real-time, a laser anemometer based on CW coherence detection was designed with eye-safe band 1.55 μm. The system optical path employed the all-fiber structure to enhance the operational stability. The telescope adopted a coaxial transmission structure with effective aperture of 70 mm and focusing distance of 80 m. The backscattered signals were processed by using the on-board programmable gate array chip on the A/D capture card and spectral centroid algorithm was also designed for wind velocity estimation. The anemometer realized high real-time and reliability. The long-term radial wind speed measurement results proved that the laser anemometer output signal was stable with a time resolution of 1 s and the lower limit of the wind measurement range was about 0.915 m/s. Compared with a calibrated pulsed coherent wind lidar, the correlation coefficient of wind speed data measured by the two devices was 0.997, the standard deviation was 0.090 m/s, and the maximum difference was 0.480 m/s.

In order to better detect the vertical profile of the tropospheric atmospheric water vapor, some improvements have been made to the established 935 nm differential absorption lidar. Taking the dual-channel receiving measure, the near-field channel telescope is also a beam expander that emitted laser light. The polarizing beamsplitter and quarter wave plate were used to isolate emitted light and echoed light in near-field channel, cassegrain telescope was applied in the far-field channel(main channel), thereby the near-ground dead zone of the lidar was reduced. The wavelength was shifted to 936.0-936.5 nm. The power of seed laser and the purity of the emission spectrum was increased, thereby the detection accuracy was improved. The detection span range was extended from 600-2 000 m to 250-3 000 m, and the random error was 5%.

The intensity of background radiation directly determines the sensitivity limit of the infrared telescope system and directly affects the system design. Background radiation is also an important index to reflect the astronomical observing conditions and performance of observatory stations. The atmospheric infrared background radiation of Ali, Delingha Observatory and Huairou Observatory astronomical observatories were measured, particularly the first-hand data of atmospheric infrared background radiation were obtained for the Ali astronomical observatories. The measured results show that the atmospheric infrared background radiation intensity and the diurnal variation of the radiance on the Ali astronomical observatories are the smallest among the three stations, and the average values of the highest radiance is 1.30×10-6 W·cm-2·sr-1. The maximum diurnal variation of Ali′s radiance mean value is only 18%. Therefore, the lowest infrared background radiation limits is Ali astronomical observatories. The second is Delingha Observatory. Finally, the measured radiance in sky sweeping was compared with the MODTRAN software simulated radiance. It is found that there is quite a difference between the simulation results and the actual measurement in the high altitude areas of the Qinghai-Tibet Plateau, whether it is the standard atmospheric mode or the actual atmospheric mode.

Based on the correlation properties of photons generated during the process of the stimulated parametric down-conversion, a system for infrared standard transfer radiation measurement was constructed, which required no refrigeration and only used visible light detector. Firstly, the operating principle of the infrared standard transfer radiometer system was described in detail. Then, the calibration coefficient of the system was acquired by using the standard blackbody fitting, and the relationship between the temperature of the infrared standard transfer radiometer and the response value of the blackbody to be measured was obtained. Finally, the uncertainty of the infrared standard transfer radiometer system was further evaluated and verified by being compared with the radiation temperature retrieved from the response value of water-bath blackbody at the same temperature. The experimental results show that the joint uncertainty of the infrared standard transfer radiometer for measuring the radiation brightness of the water-bath blackbody is 1.64%, indicating that the infrared standard transfer radiometer can be used as the transfer standard of the blackbody to the user sensor.

It is difficult to detect the defects in blades with complex profile due to the complex structures, thus nondestructive testing on this type blade has attracted abundant attentions around the world. In this paper, based on the frictional heat generation model of the defect-containing medium under ultrasonic excitation, the heat flow conduction was analyzed and the surface temperature field of the simplified model about cracked blades was derived. For the heat generation in cracked fields of blades with complex profile, finite element method was applied to numerical simulation. According to the simulation result, the longer the excitation time was, the greater the temperature rise in the crack defect field was; the rate of temperature rise presented a trend that the rate rose first and then fell with time. The steam turbine blade with a crack was tested by the detecting platform of ultrasonic infrared thermal imaging. The result of test shows that the heat generation field is most obvious in the cracked field and the result is most clear for the crack in this blade when the preload is from 100 N to 150 N. According to the numerical simulation and test, ultrasonic infrared thermal imaging technology can efficiently detect cracks defect in blades with complex profile, it has a definite guiding significance on engineering and a broad application prospect.

The thermal time constant is a key indicator of the uncooled infrared detector based on the microbolometer, it is highly related to the effective frame rate of the detector. Therefore, it is necessary to measure thermal time constant for device design and application. However, the typical design value or the measurement result based on mono-element is not easy to establish the quantitative relationship with the frequency-response characteristic of the detector. In this paper, a method for measuring thermal time constant based on array devices was introduced. The method employed a chopper to obtain a chopping frequency that was less than 1/2 frame rate, after the fast Fourier transform calculation, fitting the frequency response curve by the effective voltage response signals at different frequency point, the thermal time constant could be quickly and effectively extracted. By the experiment proving and results analyzing, the method has the advantages of high precision accuracy, strong anti-interference ability, good stability and short test time. What′s more, there is no special requirement for testing instruments or testing samples, and is worthy to be popularized.

In the complex combat environment, the infrared flares was used by a plane to counter the recognition and tracking of infrared imaging seekers in order to affect guidance precision of missiles. Through the analysis of main influencing factors, the effect mechanism of infrared flares on imaging missile was revealed. First, the simulation model of infrared flares, target plane and missile guidance link were established. On the basis of analyzing and summarizing the main influencing factors of infrared flares, the effects of infrared flares launch distance, seeker target recognition time and launch interval of multiple flares were evaluated respectively. The sumulation results of the influence of various factors on the guidance and seeker systems were proposed. The influence mechanism and discipline of infrared flares on infrared imaging missiles were summarized and analyzed.

High-precision pulsed laser ranging system is always one of the hot topics in the field of laser ranging finder. The existence of ranging error has a direct impact on the results of laser ranging accuracy. The study of differential signal moment discrimination has not been reported. Therefore, it is of great significance to study the differential time discrimination method. The factors affecting the accuracy of pulsed laser ranging were analyzed. It was considered that the time jitter caused by the amplitude-time swimming effect and the rise-time swimming effect was the most dominant factor affecting the ranging accuracy. It can be seen from the analysis that the differential signal time discrimination circuit designed can effectively improve the ranging accuracy and meet the design requirements. In the experiment, the single-distance measurement errors of different distances (<70 m) were kept within 9 mm by the differential signal time discrimination circuit. The single-end signal time discrimination circuit had a single range accuracy ranging from [-12 mm, 11 mm]. Compared with the single-end signal single-distance measurement error, the ranging accuracy is significantly improved. This method can provide reference value for how to improve the accuracy of pulsed laser ranging technology.

Blue-green laser has an important application prospect in the fine detection of underwater targets. Based on the fast numerical traversal algorithm of the head-tail circumferences, the laser scanning detection process of underwater targets was numerically modeled by establishing the intersection equation of the scanning beam and the moving target. The results show that the shortest time for the target to cross the beam scanning area does not occur in the case of the head-on encounters. Secondly, by Monte Carlo simulation, the effects of pulse frequency, scanning frequency, scanning half angle and target distance on the detection probability were simulated and the optimal design of scanning parameters was obtained. The established numerical model can provide a theoretical basis for the reasonable design of underwater laser detection system in this paper.

In order to improve the uniformity of the laser diode beam, a homogenization system combined aspheric and microlens lens array was designed. The aspheric homogenization lens was designed by using ray tracing in the direction of the fast axis, and the microlens array was used to segment and overlay the beam in the slow axis direction. Laser diode output beam passed through the honogenizing system, the energy homogenization of the square spot can be obtained on the target surface. By using Zemax optical software to simulate the single tube and array, the feasibility of the optical system was verified. The influence of target dynamic range change on uniformity was obtained, and the influence of the change of the distance between micro-cylindrical lens arrays and the rotation of fast-axis homogenizing lens on the uniformity was studied. The homogeneity of single tube and laser array on the output surface was over 90%, and the energy efficiency was 95.4% and 96.2%, respectively. The design results have certain reference value for the beam homogenization of laser diode.

Single photon laser height measurement has become a trend in the field of laser altimetry. Referring to the data processing algorithms of laser point clouds at home and abroad and the accurate analysis of the characteristics of the single photon laser data with the high repetition rate and profile along the track, a single photon laser data processing method based on Terrain Correlation and least square curve fitting was proposed. The experiment using the photon cloud data obtained by NASA′s airborne Lidar—MABEL(Multiple Altimeter Beam Experimental LiDAR) was implemented, and the accuracy was validated by the simulated data. The results show that the method can effectively eliminate noise, and the overall precision can reach to 97.8% in the experimental region.

In order to generate true random sequences, a random number extraction algorithm with variable frame rate was proposed by using laser speckle video of atmospheric turbulence as entropy source of random number generator. Firstly, an image sampling method with variable frame rate was proposed to reduce the effect on randomness of high correlation between adjacent laser speckle images. Secondly, random numbers were extracted by processing the experimental data according to the random jitter characteristics of the centroid of laser spot caused by atmospheric turbulence, dividing the speckle images into different gray levels, and executing encoding and post-processing operations. Finally, experimental analysis for the extracted random sequence was carried out by the NIST test tools. Result shows that this sequence not only reachs the standard of true random numbers, its amount and randomness are also higher than those of the random sequence generated by the equal frame rate sampling method. In addition, the relationship between the normalized variance of laser speckle video and the optimal sampling interval was analyzed, which provided an important basis for further research.

Precision sensing and measuring based on optical trap technology is innovation and deepening for application of optical force effect from micro-precise manipulation to precise measurement of physical quantities. Precision measurement of position information of the particle in optical trap is key technology of precise sensing and measuring. The method was put forward, which used digital image processing and curve fitting algorithm to detect particle positions in optical trap. The normalized self-correlation function of particle positions was obtained by digital image correlation, and the quadratic curve fitting was used to the normalized self-correlation function curve by least-square method to realize particle position detection of sub-pixel accuracy. Experiments show that the method described in this paper can effectively suppress the quantization effect of hardware and realize fast and high-precision detection of particle position in optical traps. Compared with the direct correlation method, the detection accuracy can be improved by at least one order of magnitude to 0.03 pixel.

In order to improve disturbance rejection capability and dynamic response characteristics of airborne photoelectric stability platform, the improved control method study was conducted on platform based on Linear Active Disturbance Rejection Control (LADRC). The Model-assisted Reduced-order Linear Extended State Observer (MRLESO) was used by the improved Linear Active Disturbance Rejection Controller (ILADRC), and used output of system and differential of output were used to generate the control quantity, which not only reduced phase lag and burden of observer, improved ability of estimation of observer, but also reduced the negative effects of observer with lag and estimation error of control law. The simulation experimental results show that the ILADRC had better frequency domain characteristics in the low-middle frequency band, ILADRC had better dynamic response characteristics in step response experiment, under the conditions of system had no input, sine wave moment disturbance and sine wave angular velocity disturbance with amplitude are ?仔 and frequency of 2.5 Hz were applied to the system, the residual peak value of system output based LADRC were 0.175(°)/s and 0.566(°)/s. The residual peak value of system output based ILADRC were 0.175 (°)/s and 0.566 (°)/s. The simulation results demonstrate the validity of improved control method.

With the development of multispectral, hyperspectral and hyperspectral detection technology, the technology of detecting and recognizing the detailed spectral radiation characteristics emitted by the space target became increasingly mature. A model for calculating the fine spectral effective radiation of the space target was established. Considering the influence of terrain and atmospheric environment on the spectral effective radiation of the space target, the temperature and fine spectral effective radiation of each surface of the space target under the traditional method and two typical terrain conditions were calculated respectively. The effective radiation intensity of the space target at 3-5 μm and 8-14 μm bands was analyzed with respect to wavelength. Finally, the radiation characteristics of space target at 8.69-9.00 μm detection band under different terrain conditions were analyzed. The results show that the terrain conditions had a great influence on the temperature and effective radiation of the space target, especially the surface albedo had a great influence on the solar radiation reflected by the earth. For the surface of the space target facing the earth, the maximum temperature difference could reach 69.2 K under the two typical conditions, and the deviation of spectral effective radiation emittance reached 7.002 W/(m2·μm).

When using Time-Of-Flight(TOF) camera to obtain depth values, corner distortion and precision offset often occur. At present, the main methods to compensate depth errors are based on the techniques like error look-up table or curve fitting, which has a large amount of calculation resulting in slow compensation speed. By analyzing the depth error distribution law of TOF camera at different distances, a real-time and high-precision error compensation method was proposed. The error compensation model was simplifed by using the rotational symmetry of TOF depth image and the characteristics of error distribution. The order of magnitude of the parameters was reduced, and the accuracy and speed of compensation process were effectively improved. The proposed algorithm was applied to Kinect v2 depth sensor for depth compensation, the flatness error within the effective distance dropped to 0.63 mm, the average error dropped to 0.704 0 mm, and the single frame data compensation time was less than 90 ms. Since the algorithm compensates only based on the optical path difference, it is suitable for all TOF principle cameras. The results of experiments show that the proposed algorithm can quickly and effectively reduce the depth error of TOF camera, and is suitable for real-time, high-precision three-dimensional reconstruction of large field of view.

Due to the large size and low operating temperature of the ultra-large diameter in-orbit assembly infrared telescope, mutual interference between assembly modules, the traditional thermal control methods cannot fully meet its requirements. In order to meet the proposed thermal design index, the external thermal environment analysis of the SE-L2 orbit was completed, and a five-layer sunshield for the ultra-large diameter in-orbit assembly infrared telescope was designed. The telescope finite element model was established and then simulated with the UG software. The simulation results show that after being shaded by the sunshield, the intensity of the thermal radiation from the sun, which is 1 296 W/m2, reduces to 0.036 W/m2 when it reaches the low temperature area. 210 days after the sunshield is unfolded, the temperature of this kind of telescope reduces to less than 50 K, through passive cooling radiation, meeting the demand of thermal control. This design is a valuable reference on the Chinese future construction of ultra-large space telescope because of the research on its thermal control.

Aiming at the target craft′s ground-based optical observation and attitude surveillance mission, the imaging simulation model and method of ground-based optical-telescope was studied. Based on complex target 3D modeling, orbit determination and optical imaging chain modeling, combining with the scattering characteristics of surface material properties and the imaging performance of telescope, the target craft′s optical image sequences were simulated by utilizing Open Graphics Library(OpenGL). By comparing with theoretical analysis, the field of view images of Satellite Tool Kit(STK) sensor and actual observation images, the simulation method and results were proved to be effective and credible. This research can provide references for the observation mission plan of target craft, on-orbit attitude and exterior inspection, as well as the space target attitude recognition and target identification.

According to the requirements of light weight and high stiffness of deep space exploration camera, an ultra-light main support structure was designed. The deep space exploration was more severe than the earth exploration environment. As the main bearing structure, the main supporting structure should have high stability in launching and orbiting to keep the relative position between the optical components. In contrast to traditional methods, topology optimization was used to obtain optimal load path with clear topological results of the main support structure, and then the fundamental frequency of the main support structure was improved by size optimization. At last, the lightweight design was adopted, and the weight reduction rate of the front and rear frame structures was over 90%. The results of finite element analysis and test show that the integrated main supporting structure can meet the requirements of tolerance and the basic frequency(80.264 Hz) is much higher than the requirement of 1st frequency of satellite. The method of applying optical measurement has a tilt angle of 3″ and 0.3″ relative to the rear frame before and after the vibration, which satisfies the tolerance requirements of the optical system and has good stability. The wavefront aberration of the system after a large number of mechanical experiments is below λ/14, which satisfies the imaging quality requirements of optical systems.

For meeting the requirement of complicated design restrictions, a set of performance indices was proposed, which was used to evaluate the efficiency of a space telescope secondary mirror adjusting mechanism. Based on these indices, a set of dimension parameters with high efficiency was obtained. By establishing the kinematic model, error model, statics model, dynamic model and analyzing the characters of these models, the Workspace Efficiency Index (WEI), Error Efficiency Index (EEI), Force Efficiency Index (FEI) and Energy Efficiency Index (EnEI) were proposed. The performance atlases method was used to investigate these indices. Four performance atlases of these indices were presented. Furthermore, a set of dimension parameters ((a, b, l)=(197 mm, 643 mm, 1 260 mm)) with high efficiency was obtained by optimizing these indices. The research result is helpful for engineering applications of this mechanism.

The fast steering mirror is a commonly used image motion compensation device in space cameras. The mechanical properties of the support structure will directly affect the response speed and closed loop bandwidth of the fast steering mirror system. A fast steering mirror driven by voice coil motor in a low earth orbit space camera was taken as the research object, and a two-axis flexible support structure based on cross-shaped flexible hinges was designed, which had the advantages of compact structure and small center drift. According to the approximate differential equation of cantilever beam deflection, the mathematical model of the rotational stiffness of the two-axis flexible support was established. The main structural parameters of the flexible hinge were selected for the resonant frequency requirements of the fast steering mirror mechanism, and a modal analysis of the mechanism was performed by using the finite element software MSC.Patran. The analysis results show that the resonant frequency of the fast steering mirror mechanism in the two working directions is 18.6 Hz and 18.7 Hz, while the resonant frequencies in other non-working directions are above 292.2 Hz, which proves that the choice of flexible hinge structural parameters is reasonable. In order to test the correctness of the theoretical model, a prototype of the fast steering mirror was processed and the experimental platform was built. The rotational stiffness and resonant frequency of the mechanism were tested. The results of the test and the theoretical analysis are consistent within the allowable error range.

Computational lithography is an effective way to improve the lithographic imaging performance. However, most computational lithography technologies are usually established in an ideal lithography system without considering the impact of system errors. In fact, the stage vibration among the system errors can increase the lithographic pattern error and decrease the process window(PW). Therefore, it is imperative to reduce the impact of stage vibration on lithographic performance. For the first time to our knowledge, a lithography system holistic optimization method with low stage vibration sensitivity was proposed. Firstly, the source was represented by Zernike polynomials for easing the computational burden and improving the source flexibility. Then a weighted cost function incorporating the influence of stage vibration which consists of critical dimension error(CDE) and depth of focus(DOF) was built. Finally, a gradient-based statistical optimization algorithm was applied to build the optimization framework. The simulations of 1D mask pattern at 14 nm node show that for the system with extreme stage vibration, compared with the traditional method, the CDE of the proposed method is reduced by 28.7%, and the PW is increased by 67.3%. The results demonstrate that this method reduces the vibration sensitivity and improves the process robustness effectively.

A systematic study on the low damage processing of titanium gemstone crystal surface was carried out. The orthogonal experiment was carried out on the CCOS numerical control small grinding head polishing machine. Different polishing liquids were used to chemically polish the titanium gemstone to effectively remove the subsurface damage during the fine grinding stage. The experiment proves that the SiO2 silicon solution has good polishing effect as an abrasive, and is suitable as a polishing liquid for processing titanium gemstone. The four factors of polishing disc type, polishing disc pressure, polishing disc speed and silica sol dilution concentration and the relationship between surface roughness and surface rickets of titanium gemstone crystal were studied, and the influence of process parameters on the process of low-defect processing of titanium gemstone was obtained. Experiments were carried out according to the optimized process parameters, and a low-defect, high-precision titanium gemstone surface was obtained. The method of grayscale correlation was employed to optimize polishing parameters. After optimization, the system was under the condition of the best combination of processing technique. Finally, a well processed titanium gemstone crystal is obtained, the surface of which possesses a roughness of 0.262 nm and the surface defect rate of the polished crystal is 1.4×10-3 mm-1.

In order to realize the stable control of the Mach-Zehnder modulator (MZM) operating bias point, a simple and effective control scheme based on the average optical power slope value detection was proposed. Firstly, the importance of MZM operating bias point stable control was analyzed. Then, the feasibility of the control algorithm was studied from the perspective of mathematical theory derivation. Then, the simulation verification was carried out by Matlab. Finally, the experiment of the MZM operating bias point stable control system was carried out on the built platform in the laboratory. The results show that this is a simple and effective ditherless bias control technology suitable for various modulation formats, and the experimental observation results show the performance of bite error rate of the system did not drop within 72 hours and maintain at 10-9, effectively ensuring the reliability of the modulation system MZM operation in laser communication.

The relationship between scanning angle and scanning control voltage of fiber interferometric optical phased array was analyzed theoretically. An experimental method of the relationship between scanning angle and voltage was proposed, which was that the scanning angle corresponding to a certain scanning control voltage was measured indirectly according to the light intensity at a fixed point in the field. In the simulation experiment, the M-Z interferometric optical path was used to simulate the two-path optical fiber interferometric phased array. By changing the control voltage of the phase modulator, the intensity of the light received at the fixed point of the field was tested, and the actual scanning angle of the optical fiber interferometric phased array was calculated. The experimental results show that when the scanning control voltage is in the half-wave voltage range of phase modulation, and the scanning control voltage is much lower than that of integrated waveguide arrays, the scanning angle is 0-6.2 mrad. In this range, the experimental value of the scanning angle is in good agreement with the theoretical value of the scanning angle. The simulation experiment can provide a reference for further study of far-field scanning characteristics of optical fiber interferometric phased array.

The calculation curves of the refractive index and absorption coefficient of ZnTe electro-optic crystal with the frequency of terahertz wave were given, and the phase velocity and group velocity of terahertz wave propagating in ZnTe were compared. Through the electro-optic efficiency response function related to terahertz frequency and crystal thickness, the detection spectrum response of ZnTe electro-optic crystal to terahertz pulse was calculated theoretically and the relation between terahertz spectrum response bandwidth and crystal thickness was gotten qualitatively. From the calculation result, some detection blind spots were found such as 5.3 THz and 6.2 THz which come from the lattice resonances of ZnTe crystal with corresponding frequency terahertz wave. With a large aperture terahertz photoconductive antenna and a 1 kHz pulse repetition frequency terahertz time-domain spectroscopy experiment system, six optimum matching angles between the polarization direction of terahertz pulse and the crystal axis direction of type ZnTe crystal were obtained experimentally by differential detection technology. The curve and empirical formula of the change of the maximum terahertz electric field with the angle between the crystal axis and terahertz wave polarization direction were given, which will be beneficial to in-depth understanding of the phenomenon and the effective improvement of detection sensitivity in practice.

A 0.2 THz high power doubler multiplier was designed and realized based on six anodes in parallel-series GaAs planar Schottky diodes. The Schottky diode was flip-chiped on the 50 μm thick quartz. The efficiency of the circuit was simulated combined of EM simulator and circuit simulator. The measured efficiency was bigger than 5% over the band of 190 GHz to 225 GHz with the input power of 100 mW. The circuit output power and efficiency were measured under the condition of small and large input power as 100 mW and 300 mW. The peak efficiency was 14% at the frequency of 193 GHz and the maximum output power was 14.5 mW with the input power of 100 mW under the self-biased condition. The measured output power was bigger than 10 mW over the band of 188 GHz to 195 GHz with the input power of 300 mW under the self-biased condition. The peak output power was 35 mW at the frequency of 192.8 GHz and the multiplier efficiency was 11%.

An incoherent self-interference digital holography imaging system based on Michelson interferometer was reported. The system recorded the holograms of USAF1951 resolution target, onion epidermal cell and herbaceous stem crosscut. Reconstructing the captured hologram by three-step generalized phase shift can effectively eliminate zero-order images and twin images, and obtain a high resolution reconstructed image. The element three in group nine on the USAF1951 resolution target can be clearly seen, with a resolution of 645 lp/mm. The effect of diffraction distance on the quality of reconstructed image was studied by analyzing the relationship between them. Moreover, a 3D image of the object can be obtained by this system through reconstruction of the hair hologram.

Aimed at the application background of embedded platform which is often limited in computing power, this paper proposed a low time complexity target tracking algorithm, CTSTC algorithm, which was suitable for complex scenes. The algorithm consisted of two parts: the main part constituted by the spatio-temporal context target tracking based on adaptive update of model and the aided target location part constituted by compressive tracking based on adaptive update of model. When the results of spatio-temporal context tracking were unreliable, the aided location part was activated. If the results of aided location were reliable, the aided location result was used to correct the spatio-temporal context tracking part. The running speed of the algorithm was close to that of the spatio-temporal context learning algorithm (STC). The test on I5CPU can reach 1 577 frames per second, which was much faster than other commonly used algorithms. It was a very fast target tracking algorithm, but the robustness of the algorithm in complex environments was improved. Using OTB2013 data set to test, compared with STC algorithm, CTSTC accuracy increased by 12.8%, success rate increased by 27.5%. The algorithm is tested on a small target tracking system with DM6437 as the core, which can achieve real-time stable tracking.

MOS resistor arrays are widely used and play an important role in infrared simulation field. As the core device in the infrared hardware-in-the-loop simulation link, the imaging effect is directly related to the accuracy and confidence of the final simulation results. At present, a series of problems, such as image degradation and coupling distortion, will occur when the infrared simulation digital signal enters the MOS resistor array. Therefore, it is necessary to analyze the imaging principle and energy transfer process of the MOS resistor array based on its imaging mechanism, and to establish a process and radiation model for a single pixel which conforms to its own physical characteristics. The accuracy and confidence of the model were quantified and verified by the functional relationship between the input signal and the output signal. These achievements could provide an important theoretical basis for future research on coupling characteristics, reverse correction models and non-uniformity correction of larger scale MOS resistor arrays, while having significant value in practical engineering applications.

In order to meet the high demand for sampling data in interactive image color editing, a new interactive image color editing method based on block feature was proposed. The change of image color was caused by the change of features of each block in the original image. Firstly, the image was divided into blocks in the LUV coordinate, and the linear correlation coefficient between UV and L was found in small blocks. The correlation coefficient was used as the feature of the block image to establish the optimal model of image color diffusion. By using the structural similarity before and after image transformation, LLE was used to simplify the optimization model. Finally, the sparse linear algebraic equations were used to solve the problem. The experimental results show that the proposed method can preserve the structure of the image and render the image color naturally in the condition of low sampling.

As an important branch of machine learning, deep learning has reached another climax of machine learning since its inception. Deep learning has excellent performance in many fields such as image recognition and classification, semantic segmentation, and intelligent driving and so on. At the same time, deep learning algorithms are widely used in the field of optics such as computational hologram generation and imaging, non-parameter reconstruction of digital holography, and spectral resonance curves prediction due to their abstract feature recognition and extraction characteristics, strong model building and generalization capabilities. This article detailed the basic principles of deep learning and its typical application research in image classification, super-resolution imaging, computer generated hologram and digital holography, prediction of surface plasmonics resonance curves, and structural design of metasurfaces. And future development of deep learning in the physical optical field was worth exploring.