物理学报2017，Vol.66Issue(18)：89-98,10.DOI:10.7498/aps.66.184202
高光谱分辨率激光雷达鉴频器的设计与分析
Design and analysis of high-spectral resolution lidar discriminator
摘要
Abstract
An accurate aerosol optical property can be obtained by a high spectral resolution lidar (HSRL) technique,which employs a narrow spectral filter to suppress Mie scattering in the lidar return signal.The ability for filter to suppress Rayleigh scattering is critical for the HSRL.In the HSRL system,Rayleigh scattering signal is obtained and aerosol scattering is suppressed at least by a factor of 10-5 through using the narrow filter.Usually,an atomic absorption filter can reach this level.While,the gaseous absorption lines do not exist at many convenient laser wavelengths,thus restricting the development of multi-wavelength HSRL instrument.A new and practical filtering method is proposed to realize the precise detection of atmospheric optical parameters by using the reflection field of Fabry-Perot (FP) interferometer.An optical splitting system with high spectral resolution is designed and its spectral characteristics are analyzed.Based on the characteristic of hyper-spectral lidar detection signal,the variations of spectral separation ratio and Rayleigh signal transmittance with reflectivity and cavity length are discussed.Spectral separation ratio is the transmittance ratio of aerosol scattering signal to molecular scattering signal through the spectral filter.With the increases of FP cavity length and surface reflectivity,the spectral separation ratio decreases and the Rayleigh signal transmission increases.The high spectral separation ratio and Rayleigh signal transmittance can be achieved by the reflection field of FP interferometer when the FP cavity length and reflectivity parameter can be chosen reasonably.We design an FP interferometer with a cavity length of 36 mm and reflectivity of 0.4.Its spectral separation ratio is affected by the echo divergence and incidence angle.The spectral separation ratio keeps unchanged when the beam divergence angle is within 3 mrad and the incident angle of the beam is within 0.5 mrad.In addition,a simulation analysis model is established based on the error propagation.An observed actual Mie-scattering profile is used for analyzing the errors.Moreover,the influences of the divergence angle and the incident angle of the echo beam on detection results are also discussed.The results show that the proposed FP interferometer can achieve fine spectral separation of Mie and Rayleigh scattering signal,and the error of detection result is not sensitive to laser divergence angle.Fine aerosol optical parameters can be achieved when the divergence and incidence angles are controlled within 10 mrad and 1.5 mrad,respectively.关键词
激光雷达/高光谱/Fabry-Perot干涉仪/气溶胶Key words
lidar/high-spectrum/Fabry-Perot interferometer/aerosol引用本文复制引用
狄慧鸽,华杭波,张佳琪,张战飞,华灯鑫,高飞,汪丽,辛文辉,赵恒..高光谱分辨率激光雷达鉴频器的设计与分析[J].物理学报,2017,66(18):89-98,10.基金项目
国家自然科学基金(批准号:61575160,61308107,41627807)和陕西省青年科技新星人才项目(资助号:2016KJXX-72)资助的课题.Project supported by the National Natural Science Foundation of China (Grant Nos.61575160,61308107,41627807) and the Shaanxi Province Youth Science and Technology Talent Fund,China (Grant No.2016KJXX-72). （批准号:61575160,61308107,41627807）
