Lidar Wide Field Of View Receiving System Based On Diffraction Primary Mirror

With the development of the optical technology and of requirements of deep space detection,high-resolution,high-precision and ultra-far-distance detection are the development trends of space-based optical observation systems,and the large-aperture primary mirror system is the key of optical detection system.The key has always been the crucial research object of domestic and foreign research scholars.Limited by the system weight and manufacturing process,traditional monolithic mirrors are difficult to meet the requirements of space-based systems.Diffraction imaging technique has the characteristics of low surface accuracy requirements,lightweight and large aperture.It has become an effective way to realize the large-aperture space-based telescopes and has great potential for development.In order to study the wide field of view the Lidar large-aperture receiving system,the wide view field receiving system of the Lidar is studied,the primary mirror of the receiving system based on diffractive optical elements is designed.The main research work is as follows:In order to the study of light field phase conversion,the relationship of light field linear phase change and second-order phase change between output beam are studied.The principle of beam broadening is explained by the concept of phased array.The theory that optical phased arrays modulate beam base on changing the refractive index of the material to control the phase of all arrays.In common with optical phased arrays,by adjusting the corresponding parameters of the phase step to generate a high-order phase the diffractive optical device receive wide-field beam successfully.The coupling effect of the single lens,lenses and Fresnel lens into the optical fiber are simulated and effect of the ordinary lens broadening tested.The research results show that the optical lens can widen the receiving field of view.Optical phased arrays or diffractive optical elements are used to widen the beam,in Lidar systems,the fiber can receive the wide-field beam.Planar and curved Fresnel lenses are modeled in three dimension,imported to ZEMAX software and analyzed numerically.The view field widened effect of Planar main mirrors,and conformal Fresnel primary mirrors which conform to the rectifier surface type are studied and designed.The non-imaging diffracted light receiving system is designed with the combination of both mirrors and field elements.The system keeps high gain and large field of view at the same time.In the 1.5°half field of view,secondary focusing through the field lens and immersion lens allow light to enter the detector to a greater extent.