High-power eyesafe laser transmitter for microDoppler coherent lidar

We report recent developments at Coherent Technologies, Inc. of high-power in-band-pumped solid-state lasers for microDoppler coherent laser radar applications. Lasers based on the in-band-pumped 2.1-/spl mu/m Ho:YAG and 1.65-/spl mu/m Er:YAG solid-state materials have unique thermal properties which make them ideal for operation over wide ranges of laser pulse repetition frequency (PRF). The extremely low thermal load in the laser medium significantly reduces thermal aberrations, allowing operation with diffraction-limited beam quality at high output power over wide ranges of PRF. The low thermal load results from the close match between the pump and output laser wavelengths in the in-band pumping scheme.