0.94μm差分吸收激光雷达地基工作的进展

Advance of ground based differential absorption lidar at 0.94μm

为了更好地探测对流层大气水汽的垂直廓线,对已经建立的935 nm差分吸收激光雷达进行了部分改进。采取双通道接收的措施,近场通道望远镜同时也是发射激光的扩束器,近场通道采用偏振分束器加四分之一波片的方式隔离发射光和回波光,远场通道(主通道)采用平行旁轴的卡塞格林望远镜,从而减小激光雷达近地面盲区;发射机的双波长挪到936.0~936.5 nm之间,增加了注入种子激光的功率,提高发射光谱纯度,从而提高探测精度。探测范围从600~2000 m,延展到250~3000 m,随机误差5%。

In order to better detect the vertical profile of the tropospheric atmospheric water vapor,some improvements have been made to the established 935 nm differential absorption lidar.Taking the dualchannel receiving measure,the near-field channel telescope is also a beam expander that emitted laser light.The polarizing beamsplitter and quarter wave plate were used to isolate emitted light and echoed light in near-field channel,cassegrain telescope was applied in the far-field channel(main channel),thereby the near-ground dead zone of the lidar was reduced.The wavelength was shifted to 936.0-936.5 nm.The power of seed laser and the purity of the emission spectrum was increased,thereby the detection accuracy was improved.The detection span range was extended from 600-2000 m to 250-3000 m,and the random error was 5%.