Design and analysis of uitra-narrow filter of Rayleigh lidar

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.