Laser Frequency Stabilization and Shifting Applied in Narrowband Sodium Lidar System for Wind and Temperature Measurement

The sodium lidar can achieve atmospheric parameters measurement in the mesosphere by emitting a single-mode narrow-linewidth 589 nm pulsed laser to stimulate the alkali metal sodium atoms in the atmosphere at 80-110 km altitude and obtain the resonance fluorescence scattering echo signal. Laser frequency stabilization and shifting are the key technologies for the narrow-band sodium Doppler lidar to realize mesosphere atmosphere wind and temperature detection with high resolution. This paper introduces the methods of seed laser frequency stabilization and shifting applied in a sodium lidar system. The precise locking of 589 nm seed laser frequency is achieved using the normalized saturation absorption spectrum signal, and the long-term stability of laser frequency is about 2. 2 MHz; three laser operating frequencies on the sodium D-2 line spectrum are obtained by designing a cascaded double-pass acousto-optic frequency shift device. Through the experiment with sodium Doppler lidar, the wind and temperature measurement results with high resolution are obtained, and the temperature profile from lidar is compared with the result measured by satellite.