Water vapor gas laser operating at 118-microns wavelength

Experimental results on a water vapor gas laser operating at a wavelength of 118 microns are presented. A four-inch diameter, two-meter focal length mirror resonator system was used with a mirror spacing of 3.75 meters. Each half of the gas discharge was pulsed with a separate modulator capable of delivering up to eight kV at 300 amperes in a five-µs pulse at repetition rates from 50 to 500 per second. Data on laser output vs. discharge current, gas pressure, cavity length, and time separation of modular pulses are given. Typical peak-power outputs at one mm Hg pressure and three amperes per cm²current density were in excess of three milliwatts. Output coupling was achieved by means of a two-millimeter diameter hole in one resonator mirror.