Competition, Hysteresis and Reactive Q-Switching in Co2 Lasers at 10.6 Microns

High repetition rate (30–60 kc/sec) Q-switching in a CO2 laser at 10.6μ is reported. A moving mirror technique using steady mirror velocities between 16 and 30 cm/sec produces one pulse of the strongest line (P(20)) per half wavelength of travel. The usable pulsing rate is determined by, and is a measure of, the lower laser level lifetime (∼30 μsec). In a 1-W CW laser, peak powers ≈ 30 W with pulse lengths ≈ 1 μsec and average power ≈ CW power were obtained. This and related competition and hysteresis effects result from strong coupling between the lines of the vibrational-rotational spectrum due to thermalizing molecular collisions.