衍射光学系统激光雷达接收波束展宽及作用距离分析  

Analysis of Receiving Beam Broadening and Detection Range of LiDAR Based on Diffractive Optical System

作　　者：高敬涵 李道京 周凯 崔岸婧 吴疆 王烨菲 刘凯 谭淞年[3] 高阳 姚园 Gao Jinghan;Li Daojing;Zhou Kai;Cui Anjing;Wu Jiang;Wang Yefei;Liu Kai;Tan Songnian;Gao Yang;Yao Yuan(National Key Laboratory of Microwave Imaging Technology,Aerospace Information Research Institute,Chinese Academy of Sciences,Beijing 100190,China;School of Electronic,Electrical and Communication Engineering,University of Chinese Academy of Sciences,Beijing 100049,China;Changchun Institute of Optics,Fine Mechanics and Physics,Chinese Academy of Sciences,Changchun 130033,Jilin,China)

机构地区：[1]中国科学院空天信息创新研究院微波成像技术国家级重点实验室,北京100190 [2]中国科学院大学电子电气与通信工程学院,北京100049 [3]中国科学院长春光学精密机械与物理研究所,吉林长春130033

出　　处：《中国激光》2023年第5期149-158,共10页Chinese Journal of Lasers

基　　金：中国科学院重点部署项目(E03701010F)。

摘　　要：对基于衍射光学系统的激光雷达的波束展宽方法和作用距离进行了分析,介绍了实验样机的研制情况。根据实际激光雷达的成像特点并结合宽幅成像的需求,提出了离焦扩束、加柱面镜扩束以及基于衍射镜的波长变化扩束3种接收波束展宽方法,进行了仿真计算并给出了实验样机的部分测试结果。给出了扩束情况下激光雷达的作用距离表达式,同时讨论了模数转换(AD)采样量化对接收信号采样的影响,明确了接收扩束产生的增益下降可由电子学放大器来弥补的观点,并结合实际数据给出了验证结果和分析结果。Objective To ensure a detection range,the receiving telescope of lidar should adopt a larger aperture to receive more echo energy.When receiving with a singleelement detector,increasing the receiving aperture typically reduces the receiving beam width.Array detectors are commonly used to receive wide fieldofview echo signals to achieve a wide receiving beam and form a large observation width.Considering an optical system with a 100 mm aperture and 480 mm focal length as an example,it is assumed that a singleelement detector with a photosensitive surface size of 9.5μm is used for reception.For a central wavelength of 1.55μm,the corresponding receiving beam width is approximately 20μrad,which is close to the diffraction limit.The size of the detector array required to cover a receiving fieldofview of 3 mrad is 150×150,resulting in a sharp increase in the number of LiDAR channels with a coherent detection system and an extremely complex technical implementation of the system.The size of photosensitive surface of the singleelement detector increases to approximately 1 mm.In principle,one channel can realize the reception of a wide fieldofview laser echo signal.Methods Receiving beam broadening can realize the function of a detector with a large photosensitive surface.Receiving beam broadening can be realized at the primary lens or the feed,and the method of realizing receiving beam broadening at the feed can include the common aperture function of the primary lens.Following references[5-6]and the feed beam expansion method,three receiving beam broadening methods,including defocus beam expansion,cylindrical lens beam expansion,and wavelengthconversion beam expansion based on a membrane diffractive lens,are proposed.A simulation calculation was performed.Some verification results are provided in combination with the development of the actual system.In addition,considering the problem of receiving gain reduction caused by beam expansion,the working distance equation of LiDAR in the case of beam expansion is also pro

关 键 词：遥感 激光雷达 衍射光学系统 激光扩束 宽视场接收 雷达方程 

分 类 号：TN958.98[电子电信—信号与信息处理]