Optical pumping of chemical HF lasers on the basis of NF3–H2 and ClF5–H2 mixtures by an open surface discharge in the bleaching-wave mode

Lasing on HF upon optical pumping by emission of an open discharge, using NF₃ and ClF₅ as donors of fluorine atoms, was obtained for the first time in a chemical laser and the bleaching-wave mode was realised in a chemical HF laser. An open surface discharge was used as a pump source. The velocity of the bleaching wave, which was formed under its action, reached ~8 km s^-1. The formation of this wave leads to a rapid (with an ultrasonic velocity) replacement of the working medium in the lasing region, which provides a quantum laser efficiency close to unity. The optimum compo-sition of the working mixture was found to be NF₃:H₂:Kr = 6:10:125 Torr. For this composition, the output laser energy in a 3.2-μs pulse reached ~0.4 J and the specific output energy was 3.5 J litre^-1. Approximately the same output characteristics of laser emission (0.35 J in a 3.5-μs pulse in the ClF₅:H₂:Kr=3:20:50 Torr mixture) were obtained in the system using ClF₅ as donors of fluorine atoms.