Comparative characteristics of subsonic and supersonic oxygen–iodine lasers

Comparative tests on subsonic and supersonic oxygen–iodine lasers with a gain length of 5 cm were made under identical conditions. The addition of nitrogen to the oxygen stream at temperatures up to 80 K made it possible to reach laser powers and efficiencies in the subsonic regime comparable with those or even higher than in the supersonic regime.The maximum chemical efficiency of the subsonic laser was about 21%.