Use of unstable resonators in cw chemical lasers with radial flow of a gas mixture

An analysis is made of an unstable telescopic resonator having toroidal mirrors in a ring variant of a cw chemical laser with a radial flow of a gas mixture. A method is proposed for calculating the parameters of such a laser–resonator system in the diffraction approximation using parabolic wave equations. The calculations are made for various values of the magnification in the resonator and the structure of the radiation field is studied in the near- and far-field zones allowing for optical inhomogeneities of the active medium due to the effects of a gasdynamic expansion of the mixture.