Stable high-repetition-rate single-frequency Q-switched operation by feedback suppression of relaxation oscillation.

Stable single-frequency operation of a Q-switched laser requires the initial establishment of a stable prelase, free from relaxation oscillation. Relying on natural decay of oscillation limits repetition rates and hence average power. Using feedback suppression of relaxation oscillation, a Q-switched Nd:YAG laser has operated reliably on a single frequency at repetition rates up to 25 kHz, with 88% of available cw power extracted.