Effect of medium composition on the output power from a fast-flow closed-cycle CO2 laser

It is shown experimentally that for a constant total concentration C+C_N (C is the CO₂ concentration and C_N is the nitrogen concentration), the product of the small-signal gain k₀ and the saturation parameter I_s does not depend on C and I_s ~(C+C_N)/C. This permitted us to obtain analytic expressions for the dependence of the laser radiation power on C and time if the rate of renewal of the medium and the CO₂ dissociation and recombination rates are known. The expressions derived show fairly good qualitative and quantitative agreement with the experimental data. Recommendations are made for minimizing the reduction in the radiation power with time caused by the dissociation of CO₂.