Gain measurements at 780.8 nm in a copper hollow anode cathode laser

The results of a parametric study of a copper hollow anode cathode laser operating on the He-Cu+ infrared lines are reported. The discharge voltage, the small-signal unsaturated gain on the 780.8-nm transition, and the ground-state copper atom concentration each exhibit a universal dependence on the ratio J/p of the discharge current density to the total pressure of the helium-argon buffer gas mixture. The laser output power dependencies (780.8 and 782.5 nm) on J/p, while not resulting in universal curves, have common threshold values of J/p. The threshold value of J/p for the 782.5-nm line is approximately twice that for the 780.8-nm line.