High repetition rate, continuously-pumped ruby laser

We report the first successful operation of a high repetition rate, repetitively Q-switched ruby laser. Repetition rates up to 4 kHz have been observed by employing an acousto-optic Q-switch. At rates up to 2 kHz, there is good amplitude stability with peak-to-peak variations of less than ± 10% easily obtained. Previously, using a rotating mirror Q-switch, the highest repetition rate attained was 400 Hz. At this repetition rate, peak powers of 25 kW were commonly obtained. Based on the lifetime of the metastable state of ruby (∼ 3 ms) and a pump level 3-4 times above threshold, it was previously expected that the highest achievable repetition would be approximately 1 kHz. The fact that good Q-switched outputs up to 2 kHz can be easily obtained and repetition rates up to 5 kHz can be observed was somewhat unexpected.