American directed energy maneuver-short range air defense (DE M-SHORAD) program provides air protection to the maneuvering forces by defeating, destroying, or neutralizing rotary-wing unmanned aircraft systems (UAS), fixed-wing UAS, and rockets, artillery and mortar (RAM) threats, which is one of the priorities of the army air defense and anti-missile modernization. Firstly, the development program of DE M-SHORAD system was introduced. Then, its system architecture was analyzed in detail, and the combat performance was deduced from the system parameters. Finally, the development progress of the system was reviewed. Through the comprehensive analysis, it was showed that the DE M-SHORAD system adopted the optimal components for the integration of laser weapon systems on armored vehicles through a rapid prototyping approach. In order to mitigate the technical risks, the development approach of this program was divided into two phases, first integrating and testing the 2 kW~5 kW mobile experimental high-energy laser (MEHEL), and then developing the 50 kW multi-mission high-energy laser (MMHEL). The calculation results show that the maximum range of MEHEL and MMHEL for UAS is about 0.77 km and 4.8 km, respectively.

In view of the difficulty of traditional air defense means to effectively deal with the problem of unmanned aerial vehicle (UAV) swarm, the concept of anti-swarm of rotorcraft flight platform equipped with high-energy laser was proposed. Firstly, through the study of the combat characteristics of typical swarms, the possible application modes of UAV swarms were analyzed. Secondly, by analyzing the characteristics of the existing air defense interception system, the application method of the rotorcraft flight platform equipped with high-energy laser weapons to combat the swarm was introduced. Finally, the possible application scenarios, killing modes and strike processes of rotorcraft airborne high-energy laser weapons were analyzed and studied. The characteristics of the light speed attack, point and surface killing, and all-weather strike of the high-energy laser weapon equipped on the rotorcraft flight platform were extremely suitable for the application scenarios of the swarm attack, which could more efficiently intercept the incoming swarm and reliably ensure the safety of important facilities.

Due to the differences in damage mechanisms and combat methods, the existing test methods for airborne weapons and sensors are not applicable to airborne laser weapons, and it is necessary to study the foreign special test and evaluation techniques. Starting from the test situation of typical airborne laser weapons in foreign countries, the main test phases, test contents, test categories, and management characteristics were analyzed, and the contents as well as methods of the main subjects, such as aerodynamic-optical characteristics, light emission characteristics, target detection, identification and tracking, beam control, and lethality test were studied. The results show that, in order to avoid the test technology lagging behind the research and development technology, the America has adopted the management measures of promoting relevant researches such as multi-program arrangement, vigorously construction of test machines, building of test facilities and conduct of tests in a gradual manner. It is recommended that the investment in testing technology should be strengthened, the systematic testing machines should be constructed in a timely manner, and the research in the areas of testing and targeting should be enhanced, with a view to promoting the maturation and application of new qualitative weapons.

The core structure of high-frequency terahertz (THz) filter has the characteristics of cross-scale, large removal and high precision. In order to realize efficient and precise machining of core structure, the choice of machining technology is particularly important. Compared with common machining, lithography and MEMS technology, the femtosecond laser machining technology has the advantages of strong universality of materials, simple machining flow and precision machining of thin-walled structures. The core structure of THz filter with center frequency of 850 GHz was designed as input, and the machining experiment of the core structure of THz filter was carried out by femtosecond laser machining technology. Considering that the femtosecond laser with low repetition rate could not meet the actual requirements of high-efficiency machining, the high-repetition-rate femtosecond laser was selected as the machining light source, and the high-efficiency and precise machining of the core structure of high-frequency THz filter was realized under the conditions of precise design of machining strategy and precise optimization of machining parameters. The results show that the measured center frequency of the THz filter fabricated by high-repetition-rate femtosecond laser is close to the designed value. Therefore, the high-repetition-rate femtosecond laser processing technology can be used as a flexible stage in the processing of the core structure of THz filter.

Aiming at the power measurement of high power laser, especially the long-time measurement requirements of high power laser, a laser power measurement method based on water cooling was designed. The laser power was calculated by measuring the temperature differences between the cooling water inlet and the outlet with the thermistor. The three-dimensional finite element model of the heat path structure of the absorption cavity was established by using the finite element simulation software, and the cooling water paths of different calibers were simulated. The test results show that testing the power of high power laser with this method, the measurement relative error can be guaranteed to be within 1.6%.

Femtosecond laser interacts with material shows nonlinear absorption and low thermal diffusion due to the ultrashort pulse width and ultrahigh peak power, which makes it important in the manufacturing of high-precision micro-nano devices. An ultrafast dynamic model for transient photoionization and non-equilibrium heat transfer of femtosecond laser pulses interacting with fused silica was established. By numerical solution, the spatio-temporal evolution of carrier density and non-equilibrium electron and phonon temperature of fused silica excited under femtosecond laser single pulse was obtained, and the nearly linear regulation law of electron-phonon coupling time with laser energy density and pulse width under non-equilibrium conditions was obtained. The variation laws of transient electron thermal conductivity, thermal capacity and electron-phonon coupling coefficient were further investigated in details. And the above simulation results were analyzed and discussed.

The measurement system of high energy laser beam quality factor β is mainly used for state debugging and comprehensive performance parameters diagnosis of laser system, while these parameters can evaluate the laser output performance and the far-field spot focusing ability of the laser system. Aiming at the defect that the beam quality factor β close to the diffraction limit occupying too few pixels in the area array detectors, a measurement method was proposed based on microscopic magnification with high-precision scanning slit, and the relevant scheme was analyzed and calculated. In addition, a verification scheme of measurement results using the combination of fixed aberration elements and collimator light sources was designed to analyze the uncertainty of measuring device of developed high energy laser beam quality factor β, and the measurement uncertainty was better than 10%.

An array of detectors was used to measure the distribution of laser spots in the far field, which is an important method for evaluating the laser atmospheric transmission characteristics and the performance of laser emission systems. To evaluate the performance of high-energy laser systems using array detectors, it is necessary to accurately restore the measured far-field laser spots. A laser spot restoration method based on dictionary learning for array detectors was introduced. Firstly, an improved linear interpolation algorithm was used to interpolate the original low-sampled spots. The K-singular value decomposition (K-SVD) dictionary learning algorithm was then implemented to restore the interpolated image, with peak signal-to-noise ratio (PSNR) and centroid shift of the spot being used for quantitatively comparison. The proposed algorithm yields PSNRs of restored images 4 dB~5 dB higher than those with traditional algorithms, and the centroid deviation in both x-axis and y-axis directions is decreased by 14.7% and 12.2%, respectively, when compared to the latter. Experimental results demonstrate that this method produces satisfactory restoration effects on visual and quantitative indicators of spot images.

The composition gradient was introduced into the structure design of HgCdTe detector, and a method was proposed to reduce the thermally excited carrier concentration near PN junction. The model of dark current mechanism was established, and the analysis of dark current components at high temperature showed that reducing the influence of the thermally excited carrier concentration on the junction was the key to improve the operating temperature of the detector. Different electric fields were built near the PN junction by using the composition gradient. The curves of dark current and noise of the sample with temperature under different electric fields show that the stronger the electric field is, the more obvious the effect of reducing the thermally excited carrier concentration near the junction. Based on the data analysis, it is proposed that the built-in electric field generated by the composition gradient of 103 V/cm can inhibit the diffusion movement of thermally excited carriers to the junction region, which effectively reduce the concentration of thermally excited carriers near the junction region.

The non-mechanical laser beam scanning system has advantages such as small size, light weight, and easy integration, and has great application prospects in fields such as LIDAR, laser weapons, and laser communication. Its aperture determines the working distance, scanning accuracy, and target destruction ability of the equipment. A fully electrically controlled large aperture laser beam scanning system based on a liquid crystal polarization grating was designed. Based on a liquid crystal polarization grating assosiated with a liquid crystal spatial light modulator, the large-angle continuous scanning of the beam was achieved. A beam scanning system and focused on analyzing the control strategy of cascaded liquid crystal polarization grating groups was designed, providing specific control methods. Finally, a preliminary scanning experiment of the laser beam was conducted, achieving a deflection of the 70 mm aperture beam at ?16.575°~16.575°. The research results provide technical support for the non-mechanical scanning control of laser beams, and make preliminary exploration in the application of large-aperture laser scanning systems.

A study was conducted on the influence of incident pulse laser energy density on the thermal stress at the photosensitive layer (silicon dioxide layer/silicon layer interface) of a nanosecond pulse laser irradiated complementary metal oxide semiconductor (CMOS) photodetector. A simulation geometric structure model of CMOS photodetector was established. Based on the Fourier thermal conduction equation and thermal coupling equation system, the temperature rise and thermal stress at the central point of the photosensitive surface of CMOS photodetector under nanosecond pulse laser irradiation were simulated and calculated. The influences of incident pulse laser energy density on the temperature rise time evolution process and the spatial distribution of thermal stress were discussed. The simulation results show that as the energy density of the incident pulse laser increases, the peak temperature and the thermal stress at the photosensitive layer of the CMOS photodetector increase. When a nanosecond pulse laser irradiates a CMOS photodetector, the tensile stress at the photosensitive layer causes mechanical damage to the CMOS photodetector first. As the laser energy density increases, the thermal damage occurs. The research results have certain theoretical support for the study of the damage mechanism and damage effect of nanosecond pulse laser induced CMOS photodetector.

Aiming at the problem of poor frequency sweep linearity of frequency-modulated continuous wave lidar, a high-efficiency linearization pre-modulation correction method for external cavity diode laser (ECDL) with piezoelectric ceramic external cavities was proposed. Based on the ECDL model of volume grating feedback and the bias characteristics of piezoelectric ceramics, an iterative control algorithm that conformed to the physical properties of piezoelectric ceramics (PZT) was designed, and the high linearity frequency sweep laser output of ECDL was realized. The laser system could achieve a linear frequency sweep with an output bandwidth of 1.1 GHz under the repetition frequency of 60 KHz, and the residual nonlinearity could reach 10?7. The measurement accuracy at the centimeter-level at a distance of 80 m was verified through experiments, and the meter-level measurement accuracy was achieved at a distance of 3 km. The results show that the algorithm can effectively solve the linearization correction problem of ECDL of the PZT.

In a nondegenerate three-level ladder-type atomic system, the transmission spectrum of a probe field through the rubidium atomic vapor, theoretically and experimentally, was investigated by tuning the probe field intensity. An expression for the probe response was derived analytically by using the dressed perturbation method, which predicted the existence of electromagnetically induced absorption (EIA) when the probe field was no longer weak enough. Experimentally, in the D2 line of rubidium atom in a room temperature vapor cell, when switching from weak probe field to strong probe field, it was not limited to the single photon resonance condition, and the conversion of electromagnetically induced transparency (EIT) into EIA at different probe detuning was realized. The main reason for the formation of EIA was the constructive interference between secondary dressed states generated by strong probe field and coupling field, which was analyzed by using the dressed-state image. Since many applications of EIT and EIA relied on an anomalous dispersion near the resonance, a new ability to control the sign of the dispersion was introduced.

Taking a new type of complex electro-optical system as the research object, in order to address the shortcomings of poor objectivity and large allocation deviation in traditional scoring allocation method, an importance correction factor was constructed, and a reliability scoring allocation method introducing importance correction factor was proposed. Firstly, the fuzzy analytic hierarchy process was used to obtain the relative importance of the impact of functional units on the reliability of superior functional unit or system. Then, based on the relative importance, the absolute importance of the impact of functional units on the reliability of superior functional unit or system was obtained according to expert scoring rules. Finally, based on the relative and absolute importance, a functional unit importance correction factor was constructed to correct the scoring results of each functional unit. After verification and comparison, the reliability allocation value of critical functional units is at least 6% higher than the traditional scoring allocation value, and the scoring allocation method introducing importance correction factor can effectively weaken the subjective impact of the traditional scoring allocation method, release the reliability margin of critical functional units, improve the scientificity and rationality of reliability allocation of functional units, and thereby improving the reliability design level of complex systems.

Head-mounted three-dimensional (3D) display device is a common presentation carrier of human-computer interaction interfaces in the fields of virtual reality, augmented reality and metaverse. Currently, the image quality evaluation methods and systems for head-mounted 3D display are insufficient. A 3D image quality evaluation theory based on the human visual system was proposed, and a 3D image quality evaluation method and the corresponding system were designed. Some parameters including depth reconstruction, distortion, ultimate resolution, and field angle were quantitatively evaluated. The depth reconstruction was tested based on binocular vision principle, the distortion was expressed by curvatures and polynomial transformations of specific points, the ultimate resolution was evaluated by MTF and valley-to-peak ratio of patterns, and the field angle was measured based on pinhole imaging method. In the test of two head-mounted display devices, the relative error of depth reconstruction is smaller than 3.5%, the distortion is smaller than 3%, and the field angle are 77°1′44″ and 86°56′26″, respectively. The evaluation results are highly consistent with the subjective perception of the human eyes. The proposed method and system have high engineering applicability, which are expected to play an important role in the quality assessment and design improvement of the head-mounted 3D display.

In order to measure the stress birefringence distribution of optical samples with different configurations, a multi-configuration scanning system for birefringence distribution measurement was designed based on the double elastic light modulation method. The system not only ensured the high resolution of the measurement, but improved the measurement accuracy and breadth by keeping the laser stationary and making the sample move quickly. In terms of sample measurement, the 633 nm (1/4) glass was adopted to test, the relative error of the detection results was 0.79%~0.95%, with a variation range of 0.12 nm, and the standard deviation was 0.035 2. The variation range of the BK7 glass sample was 0.25 nm, and the standard deviation of the experimental results was 0.038 9. For scanning accuracy, the continuous scanning accuracy error does not exceed 0.05 mm, and the continuous inching scanning accuracy error is less than 0.009 mm. According to the above two experimental results, it can be concluded that the multi-configuration scanning system can effectively solve the problem of high precision stress birefringence measurement in any area of the sample.

Aiming at the problems of difficult target feature extraction and unstable tracking in low-light scenes at night, a multi-target pedestrian detection and tracking algorithm based on the autoencoder structure and improved Bytetrack was proposed. In the detection phase, a multi-task auto-encoding transformation model framework based on you only look once X (YOLOX) was built, considering the physical noise model and image signal processing (ISP) process in a self-supervised manner, learning the intrinsic features by encoding and decoding the real illumination degradation transformation process, and realizing the object detection tasks by decoding bounding box coordinates and classes based on this representation. In order to suppress the interference of background noise, the adaptive feature fusion module ASFF was introduced in the target decoder neck network. In the tracking phase, it was improved by Bytetrack algorithm, and the appearance embedded information extracted based on the Transformer re-identification network as well as the motion information obtained by the NSA Kalman filter was used to complete the data association through an adaptive weighting method, and the Byte twice matching algorithm was used to complete the tracking of pedestrian at night. The generalization ability of the detection model was tested on the self-built night pedestrian detection data set, and the mAP@0.5 reached 94.9%. The results showed that the proposed degradation transformation process met the realistic conditions and had good generalization ability. Finally, the multi-target tracking performance was verified through the night pedestrian tracking data set. The experimental results show that the proposed multiple object tracking accuracy (MOTA) of the night low-light pedestrian multi-target tracking algorithm is 89.55%, the identity F1 score (IDF1) is 88.34%, and the ID switches (IDs) are 15. Compared with the baseline method Bytetrack, the MOTA is improved by 10.72%, the IDF1 is improved by 6.19%, and the IDs are reduced by 50%. The results show that the proposed multi-target tracking algorithm based on the autoencoding structure and improved Bytetrack can effectively solve the problem of difficult pedestrian tracking in low-light scenes at night.

To solve the problem that circular polarization multiplexing cannot be realized by a single phase control mode, a rectangular silicon brick structure was used to design a metasurface that could realize circular polarization multiplexing holography at 1.55 μm by combining transmission phase and geometric phase. The simulation results show that under the illumination of left circularly polarized light and right circularly polarized light, two clear holographic images can be observed in the far field, with transmission efficiency of 60.8% and 61.5%, and polarization conversion efficiency of 79.1% and 78.7%, respectively. The designed circularly polarized multiplexing metasurface has the advantages of weak crosstalk, independent design of two channels, and simple design. Moreover, the metasurface components are small in size, light in weight, easy to integrate, and have great application potential in information reuse, information storage or encoding, anti-counterfeiting, and other aspects.

The current calibration status of the lens center deviation measuring instrument was introduced, and the optical angle gauge was designed and used to calibrate the indication errors of the auto-collimated light tube of lens center deviation measuring instrument. By analyzing the basic principles of optical angle gauges, the definition of deviation angle, and the conversion relationship between deviation angle and wedge angle, a detailed explanation of how to select and use an optical angle gauge to calibrate and trace the indication errors of the auto-collimated light tube of lens center deviation measuring instrument was provided. The first-class optical angle gauges with nominal values of 2' and 5' and traced by the National Institute of Metrology were selected to calibrate a single optical path device and a dual optical path device. The measurement repeatability is better than 0.1", and the uncertainty reaches 0.11". The results show that the optical angle gauge can effectively solve the calibration and traceability problems of the auto-collimated light tube indication errors of high-precision lens center deviation measuring instruments.

Due to the leakage of frequency spectrum caused by applying fast Fourier transform to the Moiré fringe image, it becomes challenging to achieve accurate 360° full-cycle measurements. A measurement method of full-cycle torsion angle based on Moiré fringe was proposed and a set of torsion angle measurement system was built. The Moiré fringe images with different widths were acquired by a CMOS camera at 1° intervals, and then the grating frequency spectrum information could be obtained by adopting fast Fourier transform (FFT). In addition, the frequency spectrum was corrected by the Hanning-window energy centrobaric method (HnWECM), and the real and effective information of torsion angle represented by Moiré fringe image could be obtained to achieve precision measurement of full-cycle torsion angle. Experimental results show that the system can quickly and accurately realize the full-cycle measurement of the torsion angle with the advantage of wide measurement range, and its maximum error rate is 0.243 3%.

The halo effect has a negative impact on the application of detection of low-level-light image intensifier, and it is unavoidable. The method for testing the halo disappearance time of low-level-light image intensifier is lacking. To address this, a halo disappearance time test system based on digital vision was proposed. The system provided a pulse signal with a frequency of 25 Hz and an adjustable duty cycle to the LED light source through a switching power supply. 1 500 images of the image intensifier passing through a small hole with a diameter of 3.5 mm were captured by a high frame rate camera, including several complete light and dark cycles. The period information was optimized by repeatedly calculating the standard deviation to remove the periodic sequence that deviated from the average value, and the image index where the light source was turned off in the light and dark period was obtained. Similarly, the number of pictures where the halo disappeared could be obtained, thereby calculating the disappearance time of the halo. The halo disappearance time of image intensifier is 3.33 ms with the serial number GZ318118A. The test results show that the repeatability of the measuring device is 0.863%, which can effectively test the disappearance time of the halo.

The photoelectric properties of the infrared detector will be affected by the multiplier layer parameters of the internal structure. In order to improve the avalanche effect of the device, the effect of residual doping concentration and thickness of type I multiplier layer on the performance of InSb-APD infrared detector with heterogeneous SAM structure was investigated in detail with the simulation software Silvaco-TCAD. The results show that as the doping concentration of type I multiplier layer increases, the peak electric field intensity within its multiplier layer increases, and the optical responsivity increases slightly. The increase of the thickness of type I multiplier layer rises the optical responsivity and dark current density of its multiplier layer, and the peak electric field intensity decreases. Further studies show that the avalanche process is favored when the residual doping concentration and thickness of the type I multiplier layer are 1×1015 cm?3 and 3 μm, respectively.