On the presence of rotational nonequilibrium in a supersonic hydrogen-fluoride laser

Overtone small-signal gain data measured while operating a small-scale hydrogen-fluoride (HF) laser saturated on the fundamental transitions are compared with fundamental lasing output spectra and spontaneous overtone emission spectra measured orthogonal to the lasing axis. In all cases, the data are consistent with an equilibrium rotational distribution. These results are discussed in terms of their applicability to the question of rotational nonequilibrium in continuous wave HF lasers.