WA7--Electron-beam-controlled CO₂laser amplifiers

The performance of electron-beam-controlled atmospheric-pressure CO2laser amplifiers is reported. The amplifiers have an active length of 100 cm and a circular optical aperture of 10 cm2. The electrical parameters are 130-kV electron beam energy and 0.15-A/cm2cathode current density over 800 cm2; 20-kV gas pumping voltage and 7-A/cm2gas current density over 800 cm2. Referred to the gas, the corresponding values areE/N = 17townsends andj· E = 24kW/cm3. Small signal gain measurements on theP(20)line of the 10.4-μ band show gain coefficients up to 0.046 cm-1, depending on the electrical parameters and the gas composition. The operation of the amplifiers as lasers, the results of experiments on pulsed energy extraction, and the uniformity of the small signal gain across the optical aperture are reported.