Solid State Lasers for Coherent Laser Radar

CO2 lasers at wavelengths in the 10-μm region have been the main sources used in coherent laser radar system experiments, due in part to their ability to generate high, single-frequency output powers in both cw and pulsed operating modes. Improvements in the technology of solid state lasers have recently opened up the possibility that these devices can be used as alternatives to CO2-laser systems, providing more compact and reliable operation. Initial efforts have demonstrated coherent radar systems based on 1.06-μm-wavelength, Nd-doped and 2.1-μm-wavelength, Ho-doped lasers, with the latter devices favored in most cases because of the eye-safe operating wavelength. At present, the demonstrated output-power levels of solid state lasers, especially Ho-doped systems, fall well below those of CO2 lasers, and are not sufficient for challenging applications such as space-based atmospheric sensing. In this presentation we will describe some of our efforts to obtain better understanding of, and improvements in, solid state lasers for coherent laser radar.