Self-oscillation instability in fast-flow lasers with unstable resonators

An analysis is made of the influence of pumping of the active medium and energy exchange between $N_2$ and $CO_2$ in an unstable resonator zone on the operating conditions of fast-flow carbon dioxide lasers. Explicit expressions are derived for the perturbation growth rate and the dependence of the boundary of the stable region on the parameters of the medium and resonators. Estimates are made of the radiation pulse durations in the self-modulation regime.