2022
2022
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Record 217 of
Title:Design and analysis of bonding process of the space-based rectangular curved prisms
Author(s):Jia, Xinyin(1,2); Wang, Feicheng(1); Ke, Shanliang(1); Hu, Bingliang(1); Li, Libo(1); Zhang, Zhaohui(1); Li, Siyuan(1)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 12166 Issue: DOI: 10.1117/12.2617418 Published: 2022Abstract:The curved prisms have been widely used as a light splitting element because of its own focal power and can be set in nonparallel light path. When the effective light transmission area of large-size curved prism is rectangular or elliptical, it can be processed into rectangular optical elements during processing, which can reduce the volume and mass of the instrument on the one hand, and effectively block the stray light outside the field of view on the other hand. Adhesive fixation is one of the common fixation methods of optical elements, which is applied in many launched spaceborne remote sensors. However, the adhesive bonding process and adhesive strength are unstable and the bonding reliability is poor, resulting in the calculated theoretical bonding area and adhesive layer thickness are often difficult to meet the requirements of complex mechanical and thermal environment. The rigid-flexible dual mode coupling support structure for space-based rectangular curved prism was firstly introduced. And then the tensile and shear tests on the epoxy adhesive used in this project was carried out and the bonding area based on the strength test was designed. On this basis, the mechanical test of the simulator mirror group was carried out to verify the reliability of the bonding area and the design of the support structure. Finally, three bonding postures were simulated analysis and tests including prone, lateral and vertical bonding. The results showed that the vertical bonding was the smallest surface shape errors of the curved prism. Based on this bonding attitude, the bonding and mechanical tests of the curved prism were completed to verify the reliability and rationality of the bonding process. ? COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only.Accession Number: 20220911734922 -
Record 218 of
Title:Simulation of Integrated System of Photon-Counting Underwater Wireless Optical Ranging and Communication
Author(s):Yang, Haodong(1); Yan, Qiurong(1); Wang, Shanglin(1); Xiong, Xiancheng(1); Li, Peng(2); Wang, Wei(2)Source: Proceedings - 2022 International Conference on Computing, Communication, Perception and Quantum Technology, CCPQT 2022 Volume: Issue: DOI: 10.1109/CCPQT56151.2022.00024 Published: 2022Abstract:Although many researchers have achieved wireless optical ranging and communication based on Avalanche Photon Diode (APD) detectors and PIN detectors. However, due to the low sensitivity of APD and PIN detectors, their working distances are limited. In order to achieve long-distance underwater wireless optical communication, a Single-Photon Avalanche Diode (SPAD) with photon-limited sensitivity is used to detect optical signals. In addition, most literatures do not specially design the data frames of ranging and communication, which makes it difficult to perform ranging and communication at the same time. In view of the fact that there is currently no systematic solution for simultaneous communication and high-precision ranging under underwater photon counting, this paper sorts out the relevant technical details, proposes an integrated ranging and communication scheme applied to photon counting, designs a special data frame that integrates ranging and communication, and proposes an extraction and recovery scheme for ranging and communication signals. Simulation shows that this scheme can achieve underwater photon counting wireless optical communication with a communication distance of 160m and an SER of 9.75×10-6, and the ranging accuracy is better than 1.59cm. ? 2022 IEEE.Accession Number: 20224913201848 -
Record 219 of
Title:Low Temperature 808 nm High Efficiency Semiconductor Laser
Author(s):Wu, Shun-Hua(1,2); Liu, Guo-Jun(2,3); Wang, Zhen-Fu(4); Li, Te(4)Source: Faguang Xuebao/Chinese Journal of Luminescence Volume: 43 Issue: 5 DOI: 10.37188/CJL.20220025 Published: May 2022Abstract:In order to improve the performance of 808 nm semiconductor laser operating at low temperature, the temperature dependence of electro-optical conversion efficiency was studied. Combining the suppression of carrier leakage and the optimization of the series resistance, the carrier confinement phenomenon in the quantum well was analyzed theoretically. Moreover, the potential barrier height and the corresponding quantum well structure for low temperature operating were proposed, including the optimization of important parameters such as the material composition and thickness of the barrier layer, which showed significant benefit for operation under low temperature. Basing on the optimized epitaxial structure, semiconductor laser bars with a cavity length of 2 mm were fabricated. Under the temperature of -50 ℃, an electro-optical conversion efficiency of 71% was demonstrated with a slope efficiency of 1.34 W/A and an injection current of 600 A. Record high electro-optical conversion efficiency of 73.5% was reached with the injection current of 400 A, while the carrier confinement efficiency was as high as 99%, and the series resistance was as low as 0.43 mΩ. In the temperature range of -60-60 ℃, the shift coefficient of the center wavelength with temperature was about 0.248 nm/℃. ? 2022, Science Press. All right reserved.Accession Number: 20222112148900 -
Record 220 of
Title:Double layer local contrast measure and multi-directional gradient comparison for small infrared target detection
Author(s):Ren, Long(1,2); Pan, Zhibin(2); Ni, Yue(3)Source: Optik Volume: 258 Issue: DOI: 10.1016/j.ijleo.2022.168891 Published: May 2022Abstract:Infrared small target detection is one of the key technologies in the search and track (IRST) based on infrared imaging equipment. At present, the performance of small target detection based on single frame infrared image is directly related to the accuracy of subsequent target tracking, so it has been studied a lot. However, the existing small target detection algorithms have certain limitations in detection accuracy and real-time performance, especially when the contrast between the target and the background area is not high or the background is complex, especially in the complex sea or sky background, due to the influence of a large amount of noise and clutter in the background, the existing infrared small target detection algorithms have a high false alarm rate. To solve the above problems, this paper proposes a small target detection algorithm based on weighted double layer local contrast and multi-directional gradient map, which realizes the accurate detection of small targets from two aspects of targets’ local contrast and gradient. Firstly, we design an improved two layer local contrast measurement architecture, and use the weighted mean method to better represent the gray value of the local window; Secondly, a local contrast comparison method based on target and background is proposed to enhance the intensity of small targets and suppress some background clutter; Then, the multi-directional gradient map is used to further suppress the noise so as to improve the contrast between the target and the background. At the same time, singular value decomposition (SVD) method is used to extract the main features including small targets, which can effectively suppress the small texture interference around the targets in the background without losing the target intensity; Finally, an adaptive threshold method is used to separate small targets from their background. Experimental results show that compared with the existing algorithms, the proposed detection algorithm can effectively reduce the false alarm rate in different complex scenes, and the computational efficiency is improved compared with some multi-scale small target detection methods. At the same time, the signal to clutter ratio (SCR), background suppression factor (BSF) and receiver operating characteristic (ROC) curve are also better than these existing state of the art algorithms, which can display good robustness. ? 2022Accession Number: 20221211816407 -
Record 221 of
Title:The Collection Efficiency of a Large Area PMT Based on the Coated MCPs
Author(s):Wang, Xingchao(1,3); Chen, Lin(2); Wang, Qilong(1); He, Jianli(5); Tian, Li Liping(2); Tian, Jinshou(4); Shen, Lingbin(2); Wang, Yunji(2)Source: Measurement Science Review Volume: 22 Issue: 5 DOI: 10.2478/msr-2022-0030 Published: October 1, 2022Abstract:The electron collection efficiency (CE) of the photomultiplier tube based on microchannel plates (MCP-PMT) is limited by the MCP open area fraction. Coating MCP with a high secondary yield material is supposed to be an effective approach to improve CE. Both typical and coated MCP-PMTs are developed. A relative measurement method is proposed to characterize the collection efficiency performance. Results show that the PMT based on the coated MCPs has a significant improvement on CE, a good gain uniformity and a high precise energy resolution. ? 2022 Xingchao Wang et al., published by Sciendo.Accession Number: 20223412593662 -
Record 222 of
Title:Localized Modes in Nonlinear Fractional Systems with Deep Lattices
Author(s):Liu, Xiuye(1,2); Malomed, Boris A.(3,4); Zeng, Jianhua(1,2)Source: Advanced Theory and Simulations Volume: 5 Issue: 4 DOI: 10.1002/adts.202100482 Published: April 2022Abstract:Solitons in the fractional space, supported by lattice potentials, have recently attracted much interest. The limit of deep 1D and 2D lattices in this system is considered, featuring finite bandgaps separated by nearly flat Bloch bands. Such spectra are also a subject of great interest in current studies. The existence, shapes, and stability of various localized modes, including fundamental gap and vortex solitons, are investigated by means of numerical methods; some results are also obtained with the help of analytical approximations. In particular, the 1D and 2D gap solitons, belonging to the first and second finite bandgaps, are tightly confined around a single cell of the deep lattice. Vortex gap solitons are constructed as four-peak "squares" and "rhombuses" with imprinted winding number (Formula presented.). Stability of the solitons is explored by means of the linearization and verified by direct?simulations. ? 2022 Wiley-VCH GmbH.Accession Number: 20220511546844 -
Record 223 of
Title:Ultrafast Tm:CaYAlO4 laser with pulse regulation and saturation parameters evolution in the 2 μm water absorption band
Author(s):Cao, Xue(1); Zhu, Qiang(1); Xian, Anhua(1); Liu, Yangyu(1); Liu, Guangmiao(1); Li, Luyao(1); Li, Xianni(1); Xu, Xiaodong(1); Zhou, Wei(1); Wang, Haotian(1); Huang, Haitao(1); Jia, Baohua(2); Wang, Yishan(3); Wang, Jingru(4); Tang, Dingyuan(1); Shen, Deyuan(1)Source: Optics and Laser Technology Volume: 152 Issue: DOI: 10.1016/j.optlastec.2022.108096 Published: August 2022Abstract:Ultrafast solid-state laser sources operating in the mid-infrared (mid-IR) region are of significant importance in a variety of applications. However, the realization of ultrafast lasers with narrow pulse width at wavelengths between 1.8 and 2 μm has remained a big challenge due to the strong water molecule absorption. Here, we report a stable mode-locking (ML) pulsed lasing at 1967 nm and narrow pulse duration of 1.97 ps in a diode-pumped Tm:CaYAlO4 (Tm:CYA) crystal laser oscillator. By employing the SESAMs with different modulation depths as mode-lockers, we show that under the increasing saturation parameters, output pulses could be narrowed in the steady state cavity. Furtherly, the generalized Ginzburg-Landau equation is used for the mode-locked pulse dynamic evolutions. It shows that the pulse- regulation mechanism in solid-state cavity at water absorption band is governed by the balance of the laser gain, the modulation depth, and the saturation parameter. To our knowledge, this is the first demonstration of pulse regulation mechanism in the 2 μm water absorption band by a commercial laser diode in a Tm:CYA laser. Our results provide an effective method for pulse regulation of ultra-short mid-IR pulses and even few-cycle pulses with controllable optical spectra in the water absorption band. ? 2022Accession Number: 20221411884170 -
Record 224 of
Title:Single photonic integrated circuit imaging system with a 2D lens array arrangement
Author(s):Liu, Gang(1,2); Wen, Desheng(1,2); Fan, Wenhui(1,2); Song, Zongxi(1,2); Li, Baopeng(1); Jiang, Tuochi(1,2)Source: Optics Express Volume: 30 Issue: 4 DOI: 10.1364/OE.447584 Published: February 14, 2022Abstract:The segmented planar imager is an advanced optical interferometric telescope with a photonic integrated circuit (PIC). It provides a significant reduction in size, weight, and power consumption as compared to traditional optical interferometry. In this article, we propose the combination of a single PIC with a two-dimensional (2D) lens array to achieve single-PIC imaging. Unlike previous designs which require a large number of PIC arrangements in different directions for imaging, a single-PIC imaging system requires only one PIC for 2D frequency domain sampling and imaging. In addition, the single-PIC imaging system can form a larger equivalent aperture through modularization. Since PIC can be mass-produced, the modularization ability of the single-PIC imaging system greatly shortens the production and development cycle of large-aperture telescopes. ? 2022 Optica Publishing Group.Accession Number: 20220611592668 -
Record 225 of
Title:Design and fabrication of polarization and phase modulated beam splitter
Author(s):Pan, Yonggang(1); Zhang, Sibao(2); Liu, Zheng(2); Liu, Wencheng(2); Li, Mian(2); Zhang, Chunjuan(2); Luo, Changxin(2)Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering Volume: 51 Issue: 5 DOI: 10.3788/IRLA20210512 Published: May 25, 2022Abstract:Polarization and phase controlled beam splitter is an indispensable optical element in free space quantum communication system. Its performance directly affects the communication quality and determines the communication error rate. Based on the theory of equivalent layer design, the special film structure of ''dielectric+metal+dielectric'' is adopted, and Ag metal material and SiO2, Al2O3, Ta2O5 dielectric material are selected to realize 45° incident angle on quartz substrate, and the average transmittance/reflectance ratio is 8.5: 91.5 in the wavelength range from 1500 nm to 1600 nm. Phase is controlled at 1530, 1540, 1550, 1560 nm. By optimizing the deposition process, the splitter film samples are prepared by electron beam evaporation with ion assisted technology. The test results show that the average transmittance/reflectance ratio is 8.53: 91.47 in the wavelength range of 1500-1600 nm under the condition of 45° incidence. The transmitted phase difference controlled within 5.02° and the reflected phase controlled with 8.05° in the range of 1530, 1540, 1550, 1560 nm, which meets the requirements of spectral energy splitting ratio and phase control of communication system. In addition, the film passed the corresponding environmental test, which meets the reliability requirements. Copyright ?2022 Infrared and Laser Engineering. All rights reserved.Accession Number: 20222412222084 -
Record 226 of
Title:10 kW rectangular laser beam generation with incoherent space combiner
Author(s):Tian, Xiao(1,2); Bai, Yang(1); Lei, Guangzhi(3); Yu, Lidong(1); Zhou, Jingfeng(1); Li, Ben(1); Wang, Yi(1)Source: Optik Volume: 260 Issue: DOI: 10.1016/j.ijleo.2022.169011 Published: June 2022Abstract:In this paper, we report an incoherent space laser beam combiner for rectangular beam combination with 18 fiber-transmitted semiconductor lasers at 972 nm wavelength. The coupled thermo-mechanical properties of all the optical lenses in the combiner were analyzed to evaluate the long-term reliability of the combiner subjected to beyond 10 kW high-power laser irradiation. An experiment-based numerical model was developed on the basis of the multi-beam laser volumetric heat source, and the performance of lenses irradiated by 10 kW combined laser for 1000 s was studied with finite element method (FEM). The maximum temperature among all lenses was 427.27 K which is much lower than the softening point temperature of fused silica material made of lenses. And the 0.1 aperture number corresponding to the maximum thermal deformation of 4.53 μm is much smaller than the conventional optical lens processing tolerance. The maximal stress of 12.73 MPa is far less than the yield stress of 4.5 GPa for the material. The manufactured laser beam combiner realized a highest output power of 10.641 kW at a power combination efficiency of 98.5%, a combination length of 200 mm and a rectangular focal beam spot of 30 mm × 10 mm. Our method provides a valuable choice for realizing fast and flexible laser surface heat treatment. ? 2022 Elsevier GmbHAccession Number: 20221611980034 -
Record 227 of
Title:Residual Stress and Deformation of 1 064 nm High Reflection Films for Laser Systems
Author(s):Li, Yang(1); Xu, Jun-Qi(1); Su, Jun-Hong(1); Yuan, Song-Song(1); Liu, Qi(1); Liu, Zheng(2)Source: Surface Technology Volume: 51 Issue: 9 DOI: 10.16490/j.cnki.issn.1001-3660.2022.09.032 Published: 2022Abstract:The large surface shape change on the substrate after coating is due to the residual stress of the optical films. It presents a challenge for coating optical elements with high precision surface shape. The work aims to study the residual stress mechanism and surface profile shape change of monolayer films and laser high reflection films with different films on substrate. The surface shape change of the substrate is reduced by adding a compressive stress compensation layer on the outermost layer of the multilayer films. It provides a method for preparing micro-deformation laser high reflection mirrors. The residual stress mechanism of monolayer film is analyzed by the theory of thermal stress and residual stress in optical films. The equivalent reference temperature is used to replace the intrinsic stress of optical thin films, and the intrinsic stress of optical thin films is obtained by simulation. The residual stress distribution and surface shape change of laser high reflection films-substrate system is studied by finite element analysis and experiments. Based on the stress of monolayer film, the residual stress distribution and surface profile change of high reflection films-substrate system is simulated and analyzed by equivalent reference temperature, birth and death element and load step technology. Different high reflection films are prepared by thermal evaporation of electron beam. The effects of initial substrate surface profile, films material and films combinations on high reflection films-substrate system are analyzed via testing surface profile changes of it, using Zygo laser interferometer. The simulation results show that the residual stress of high reflection films-substrate system is layered. It changes from tensile stress to compressive stress and then to tensile stress in the direction from the substrate to films. The surface profile of high reflective films-substrate system is concave and the Z-axis displacement is distributed annularly due to residual stress. By analyzing the influence of monolayer film on the substrate surface shape and comparing the residual stress value of each film layer in different high reflective films systems, it is found that the surface profile change of G│(HL)10H2L│A is smaller than G│(HL)10H│A with TiO2/SiO2. The surface profile of substrate with high reflective films (fused silica substrate, 30×2 mm) is basically unchanged (ΔPV=0.004λ) because the residual stress of films reduced by adding a compressive stress compensation layer, which is consistent with the simulation results. On the fused silica substrate, the intrinsic stress of TiO2, HfO2, H4 and SiO2 plays a leading role in the residual stress. The residual stress of TiO2, HfO2, H4 is tensile on the fused silica substrate while the SiO2 is compressive. All the high reflection films systems with different material combinations show compressive. For TiO2/SiO2, the films-substrate system G│(HL)10H2L│A is smaller than G│(HL)10H│A in residual stress of optical films and the change of surface shape on substrate. Its residual stress value is –39.70 MPa, which is 22.26 MPa less than that without stress compensation layer. Its surface shape has basically not changed. The addition of 2L (stress compensation layer) balances the residual stress of the multilayer films-substrate system without affecting the spectral characteristics. ? 2022, Chongqing Wujiu Periodicals Press. All rights reserved.Accession Number: 20230713580664 -
Record 228 of
Title:Research on Precision Positioning Technology of High Dynamic Target Based on Motion Platform
Author(s):Xie, Meilin(1,2); Cao, Yu(1,2,3); Lian, Xuezheng(1,3); Huang, Wei(1,3); Hao, Wei(1,3); Feng, Xubing(1,3); Wang, Fan(1,3); Liu, Peng(1,2,3)Source: IEEE 6th Information Technology and Mechatronics Engineering Conference, ITOEC 2022 Volume: Issue: DOI: 10.1109/ITOEC53115.2022.9734683 Published: 2022Abstract:The research on the high precision target measurement method and its key technology based on the motion platform can provide a new measurement system and a new mode of high precision, full function, quick response, small and light, free and flexible, close observation, high efficiency, and strong generality for photoelectric measurement field. According to different usage requirements, this article focuses on the real-time positioning requirements of the target based on the motion platform, and analyzes principle and process in detail of these four real-time high dynamic target positioning methods: single station angle measurement and distance measurement positioning method, the single-station settlement solution based on the collinear equation, the high-precision positioning solution with cooperative identification, the double - machine intersection measurement solution. Then the sources of error and methods to improve accuracy are analyzed [1]-[3]. The measurement mechanism based on motion platform in this paper can be networked with the existing range measurement system to achieve target tracking and measurement in a full range, which is conducive to enhancing the comprehensive test capability of the range and can be widely used in missile weapon system and naval navigation system and other range tests. ? 2022 IEEE.Accession Number: 20221511946742