| The optical part is the basic heart of a lidar system, which determines its functionand performance. The purpose of the paper is about how to make use of optical designsoftware ZEMAX on a lidar’s optical system, and take advantage of its powerfulfeatures to model the system and improve the optical efficiency.Water vapor, cloud and aerosol detection lidar is the paper’s research target. It ismainly used for detecting water vapor in the atmosphere. Due to water vapor’s lowcontent and weak signal, the reception efficiency concerns the success of the Ramanlidar. In addition, this lidar also detects clouds, aerosol and other atmosphericinformation, so the complex design needs simulation and optimization although thebasic design has been formed. The receiving system is divided into three parts: a fibercoupling system, a branch system, and a polychromator including six channels, threeRaman channels, a1064channel, and two532polarization channels.In order to improve the energy detection efficiency, the paper ray-traced the sixchannels with ZEMAX software. With analyzing the ray direction, aberrations, imageflare energy, the accurate relevant parameters were calculated of the entire optimaldesigned receiver as a powerful reference for assembling the system.This paper achieved the target to calculate the geometric factor by ray-tracingwith ZEMAX software. Near field signal reception efficiency of the initial design isvery low. After a detailed analysis of the lateral and axial displacement of the fiber,and tilting the telescope, the near field signal reception efficiency increased obviously.The two methods (lateral displacement and tilting the telescope) are discovered andproved the same affect. The research proposed the lateral displacement of the fiber asan alternative of the tilting of the telescope or the laser beam into practice, so that thisnot only can simplify the assembly of the system, collimate the optical path, but alsoimprove the stability of the mechanical system. |
