Reproducibility of the frequency of a ring gas laser with a nonlinear absorption cell

It is shown theoretically that a power resonance peak of a ring laser reproduces exactly the central frequency of an absorbing gas when the centers of the gain and absorption profiles coincide. A method is suggested for ensuring the coincidence of these centers: It is based on the existence of laser power resonances associated with the competition between the effects of spectral saturation of a line, spatial de-excitation of the medium, and phase interaction between traveling waves.