Continuous-wave supersonic first-overtone chemical HF laser

A theoretical analysis is reported of the feasibility of highly efficient utillisation of overtone vibrations in a cw supersonic HF laser with a slot nozzle array. The laser kinetics and the Navier–Stokes equations are solved simultaneously. The latter equations are considered within the framework of a "narrow channel" model both for single nozzles and for the mixing (lasing) zone. The following energy parameters of the overtone laser are calculated for the 2–0 and 3–1 transitions: the specific output energy, the reduced power, and the distribution of radiative loads along the direction of flow. It is shown that the overtone conversion efficiency may exceed 30% of the fundamental-tone efficiency.