Influence of spatial inhomogeneity of the gain on the properties of a laser with an unstable resonator

An experimental investigation was made of the spatial and energy characteristics of a CO₂ laser with an unstable resonator when the degree of spatial inhomogeneity of the gain of the active medium was varied. It was found that, in the first approximation, the gain inhomogeneity across the laser resonator could be ignored in estimating the angular characteristics of the output radiation provided there were no mechanisms that could cause phase distortions in the resonator in the presence of an amplitude inhomogeneity of the radiation field.