Influence of the gas flow turbulence on the angular divergence of radiation emitted from a plane-parallel optical resonator

An investigation was made of the influence of the effects of wave refraction by turbulent pulsations of the gas flow on the characteristics of the wavefront and on the angular divergence of radiation emitted from a plane-parallel optical resonator. The equation for the mutual coherence function Γ (x, x'; z) was solved numerically in the approximation of a parabolic equation with Markov (in terms of the longitudinal correlation radius) fluctuations of the permittivity. The calculations were carried out using the method of splitting by parameters. It is shown that enhancement of the turbulence flattens out the distribution of the field on the mirror and increases the angular divergence. When the angular divergence is governed by turbulent effects, the magnitude of this divergence increases also on increase in the wave number.