Transverse inhomogeneity and gain measurement in low-gain gas lasers

A method is proposed for determining the gain of gas mixtures. The results are interpreted taking into account the influence of a transverse inhomogeneity of the active medium. It is shown theoretically how the refractive index and gain inhomogeneities influence differently the modes, the eigenfrequencies, and the losses of a stable resonator with circular spherical mirrors. An equation is obtained for describing the dynamics of the complex radiation field amplitude.