Performance of an HF chain-reaction laser with high initiation efficiency

Output-pulse observations are presented for a tranverse electrically initiated, helium-diluted HF laser pumped by the H
2
+ F
2
chain reaction. Performance of this laser is studied over a wide range of the gas composition and for initial pressures between 0.1 and 0.5 atm. The gas mixture was stabilized by premixing O
2
, F
2
, and He and flowing this mixture into a cold trap (84 K) before mixing with H
2
. Optimum conversion of electrical-initiation energy into laser energy was found for a 240-torr mixture with a mole ratio 1 F
2
:0.23 H
2
:0.08 O
2
:12 He which, when initiated with a 25-kV, 333-pF discharge, gave a pulse energy of 0.150 J. This corresponds to a ratio of laser output energy to electrical input energy of 144 percent. After unnecessary losses are taken into account, this ratio becomes 160 percent.