Resonances of intensities and oscillation frequencies in ring gas lasers. I

Narrow resonances of the intensities and oscillation frequencies of counterpropagating waves in the vicinity of the center of the quantum transition in a pure-isotope ring gas laser have been studied. It is shown that the origin of resonances is related to the presence of sources causing unequal losses and/or frequencies of the counterpropagating waves in the laser cavity. The resonance change of intensities, which is accompanied by the resonance behavior of the medium dispersion for each of the waves, is not related to resonance changes of the saturated gain coefficients of the nonlinear medium. The resonances are caused by the redistribution of energy between the waves. The character of resonance changes of frequencies and intensities depends on the nature of nonreciprocity present in the cavity.