Design of fiber optic lidar for high temperature and humidity detection based on multiphysical simulation

The background radiation of sunlight seriously affects the performance of Raman LiDAR in daytime detection. In order to improve the height and accuracy of Raman LiDAR daytime detection, the author designed a Raman LiDAR system with a laser wavelength of 354.8 nm. The influence of 354.8 nm and 532 nm laser sources on the detection performance of Raman LiDAR was discussed, and the optical path design of the system was completed. The combination of a polarizing beam splitter prism and a 1/4 wave plate optical switch with a combined telescope reduces the receiving field angle of the system and optimizes the performance of daytime detection. The detection performance of the system was simulated with the minimum temperature uncertainty as the standard. During the simulation process, the laser energy is taken as 200 mJ, the frequency is 50 Hz, the inte-gration time is 20 min, and the distance resolution is 105 m. The Raman LiDAR system with integrated trans-mission and reception considers depolarization, and the temperature uncertainty detected during the day is less than 1 K below 3180 m. The statistical error of detecting the water vapor mixing ratio during the day is below 2400 m, less than 0.001gkg. The simulation results show that the performance of daytime detection has been improved to a certain extent.