Nonlinear aperture losses in the cavity of an industrial CO2 laser with transverse pumping of the gas

We study the nonlinear behavior of the refractive index of the active medium of an industrial transverse-flow CO2 laser. We consider the role of the light-induced heat release and dispersion of the medium in the formation of an optical wedge, which causes a displacement of the axis of a stable cavity relative to the selecting aperture. We show that, by a proper choice of the size and shape of the aperture, it is possible to reduce the losses that arise on the aperture under the influence of the wedge to a level not reducing appreciably the power of single-mode lasing.