Effect of M²Factor of Laser Beam for a Non-Coaxial Lidar System

Ultraviolet Raman lidar for high-accuracy profiling of aerosol extinction coefficient

“…Laser outgoing is collimated by a beam expander to reduce the beam divergence and then transmitted into the atmosphere. The return lidar signal backscattered by the atmosphere is collected by a 250-mm-diameter Schmidt Cassegrain telescope and then focused into a 200-µm-core optical fiber, which sets the field of view of the receiver to 0.2 mrad considering the effect of laser beam quality factor M 2 [13] . The output from the fiber is collimated and then coupled into the spectroscopic filter box, which is constructed with a high-spectral-resolution plane reflection grating mainly.…”