近红外高光谱分辨率激光雷达光谱滤光器性能分析

Spectrum Filter Performance Analysis on Near-Infrared HighSpectral-Resolution Lidar

近红外高光谱分辨率激光雷达(HSRL)分子散射回波信号具有频谱展宽窄、能量弱等特点,相对于紫外和可见光HSRL研发难度大大增加。光谱滤光器作为HSRL的关键器件之一,与HSRL系统的反演精度密切相关。根据光谱滤光器的信号透射率和光谱分离比与HSRL系统反演精度的关系,通过分析1064 nm HSRL散射回波的特点,对两种具有代表性的干涉光谱滤光器进行了建模和仿真分析。结果表明,在光束发散角较小时,Fabry-Perot干涉滤光器具有较好的滤光性能,但对面形精度要求较高,不易于加工和装调;视场展宽Michelson干涉滤光器(FWMI)对光束的发散角不敏感,集光能力强,且对面形精度的要求相对较低,在实际应用中更适合用于近红外HSRL系统光谱滤光器。

Near- infrared high- spectral- resolution lidar（HSRL） is more difficult to develop as its molecule scattering echo signal has a narrower spectrum width and a weaker energy strength than that of the ultraviolet and visible HSRLs. As one of the key components of HSRL, the spectrum filter has significant influences on the retrieval accuracy of HSRLs. Based on the relationship between the spectral filter′ s signal transmittance and spectral discrimination ratio and the retrieval accuracy of the HSRL, the performances of two typical interference spectrum filters are modeled and simulated by analyzing the characteristics of lidar echo at 1064 nm. Results show that FabryPerot interference filter has moderately good performances when the divergence of incident beam is small. While the requirement for surface precision is fairly high and it is not easy to be processed and installed. Field-widened Michelson interferometer（FWMI） is insensitive to the divergence of incident beam and has a stronger ability to gathering the lidar echo. And the requirement for surface precision is relatively low. In practical application, it is more suitable for the application requirement of near-infrared HSRL.