New mechanism of modulation of output radiation of a laser with an unstable resonator

It is shown that modulation of the intensity of the radiation emitted by continuous-flow lasers with unstable resonators may give rise to optical inhomogeneities. Expressions are obtained for the natural frequencies of perturbations and for the instability increment. An analysis is made of the effects of pumping of an active medium in a resonator, of the exchange of excitations between molecules, and of the relaxation process on the rate of growth of optical inhomogeneities in CO₂ lasers.