Abstract

Lidar sounding of the mesospheric sodium layer for density and temperature profiling has been conducted primarily with dye lasers.¹ This work has been very successful, and dye laser systems based on CW dye laser oscillators are precise enough to measure wind-induced Doppler shifts of the sodium fluorescence line shape.² However, there is a need for sodium fluorescence lidar transmitters based on solid state laser technology for use on mobile platforms and other locations for which dye lasers are not optimal. The first successful solid state sodium fluorescence lidar is based on a tunable Alexandrite transmitter.³ In this technique, an Alexandrite laser produces light that is Stokesshifted to 1178 nm, then frequency doubled to the 589 nm sodium line. Alternatively, tests have shown that the Alexandrite primary beam can be directly frequency shifted to 589 nm using the anti-Stokes shift. In both cases, the laser is injection seeded to ensure single mode operation and the narrow linewidth required to measure the Doppler-broadened width of the sodium fluorescence line shape.

© 1995 Optical Society of America