Amplification at 10.6 µ in the negative glow of a hollow-cathode discharge in a CO2-He mixture

An amplifier for 10.6-μ radiation of a CO
2
laser has been constructed using the negative glow of a hollow-cathode discharge. The single-pass gain of 10 percent per meter reported here from such a discharge in a CO
2
-He mixture is less than that realizable in the positive column of a glow discharge used for CO
2
lasers under comparable conditions. The addition of N
2
, CO, or O
2
was not found to increase the gain.