瑞利激光雷达超窄带滤光器参数设计及性能分析

Design and analysis of uitra-narrow filter of Rayleigh lidar

  • 摘要: 白天太阳光背景辐射严重降低雷达系统的信噪比,从而影响探测高度和精度。为实现对中高层大气相关参数的全天时测量,利用Nd:YAG激光器产生的355 nm激光束作为光源,研制了用于全天时的超窄带滤光器。从原理出发,利用FP标准具透过率曲线单支具有超窄带宽的特性,设计了一款用于进行白天观测的级联式超窄带滤光器;给出了该超窄带滤光器近似透过率函数形式,定义了滤光器性能评价函数,给出了设计方法;通过定义的滤光器性能评价函数,对超窄带滤光器主要参数进行了优化设计,给出了各光学部件具体参数,给出了超窄带滤光器的信噪比提升效果;最后,通过具体实验对各标准具及级联状态下的系统透过率进行了标定,经曲线拟合表现出较好的一致性。

     

    Abstract: The solar background radiation seriously reduces the signal to noise ratio of the lidar detection, and affects the detection height and accuracy of lidar system during the daytime. In order to obtain the relevant parameters of the middle atmosphere all time, an ultra-narrow band filter used on all time detection was developed in 355 nm wavelength of laser. First of all, an ultra-narrow band filter was designed on all time observation with the character that the band of a single pass rate curve of FPI was very narrow. Then, the approximate transmission function of the ultra-narrow band filter was infered, the performance evaluation function was defined, and the design method was given. With the performance evaluation function, the main parameters of the ultra-narrow band filter were optimized and the parameters of each optical component were given. The signal-to-noise ratio of the ultra-narrow band filter was increased 50 times than the 0.15 nm interference filter. Finally, the transmission rate curves of each optical component and cascaded etalon system were calibrated through experiment. The fitting curve shows good consistency with the experimental data.

     

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