小视场大气温湿度探测的拉曼激光雷达的设计与仿真

太阳光背景辐射严重影响拉曼激光雷达白天探测的性能。为提高拉曼激光雷达白天探测的高度和精度，设计了激光波长为354.8 nm的拉曼激光雷达系统，讨论了354.8 nm和532 nm激光光源对拉曼激光雷达探测性能的影响，完成了系统的光路设计。偏振分光棱镜和1/4波片组成的光开关与收发合置的望远镜相结合，减小了系统的接收视场角，优化了白天探测的性能。以最小的温度不确定度为标准，通过仿真分析选取了转动拉曼通道干涉滤光片的各项参数，并对系统的探测性能进行了仿真。仿真过程中激光能量取200 mJ，频率50 Hz，积分时间20 min，距离分辨率105 m。收发合置的拉曼激光雷达系统在考虑退偏的情况下，白天探测的温度不确定度在3180 m以下小于1 K。白天探测水汽混合比的统计误差在2400 m以下，小于0.001 g/kg。仿真结果表明，白天探测的性能得到了一定程度的提高。

Design and simulation of Raman lidar with small field of view for atmospheric temperature and humidity detection

The solar background radiation seriously affects the detection performance of Raman lidar during daytime. In order to improve the detection height and accuracy of Raman lidar during daytime, a Raman lidar system with laser wavelength of 354.8 nm was designed. The influence of 354.8 nm and 532 nm laser sources on the detection performance of Raman lidar was discussed. The optical path design of the system was completed. The combination of photoswitch and monostatic telescope reduced the receiving field of view angle and optimized daytime detection performance. The photoswitch was composed of polarization splitting prism and 1/4 wave plate. With the minimum statistical temperature uncertainty as the standard, the parameters of rotational Raman channel interference filter were selected through simulation analysis. And the detection performance of the system was simulated. During simulation, the laser energy was 200 mJ, the frequency was 50 Hz, the integration time was 20 min, and the range resolution was 105 m. Under the condition of depolarization, the statistical temperature uncertainty of the monostatic Raman lidar system less than 1 K was obtained up to 3180 m height in the daytime. The statistical error of water vapor mixing ratio was less than 0.001 g/kg up to 2400 m height during daytime. The simulation results show that the performance of daytime detection has been improved to some extent.