Characteristics of a high-power supersonic cw chemical HF laser with helium and nitrogen dilution

An experimental investigation was made of the influence of replacement of an inert diluent (helium) with nitrogen on the energy and spectral characteristics of a high-power (~20 kW) self-contained supersonic cw chemical HF laser with a radial-expansion nozzle array of 70 cm × 10 cm dimensions. The dependences of the laser output radiation power and of the specific output energy on the degree of dilution of the fuel mixture with helium and nitrogen were determined, and the optimal degrees of dilution were found. The output power fell approximately twofold and the specific output energy decreased by a factor of 3.6 when dilution with helium was altered to dilution with nitrogen. A double-pass four-mirror cavity was proposed to compensate for the output radiation power losses resulting from the replacement of helium with nitrogen.