Effects of translational and rotational nonequilibrium on cw chemical laser performance.
A previous model used to describe cw chemical laser performance is generalized to include rotational as well as translational nonequilibria. The resultant equations are simplified by the realistic assumption that translational and rotational relaxation rates are fast compared with convection, chemical pumping, and collisional deactivation rates. As a consequence, translational and rotational relaxation are in equilibrium with stimulated emission. A further simplification is introduced by the assumption |1-(R(t)/R(r))|(Delta nu (h)/Delta nu (d) << 1, where R(t)/R(r) is the ratio of translational to rotational relaxation rates, and Delta nu (h)/Delta nu (d) is the ratio of homogeneous to Doppler widths. The resultant system of equations is independent of rotational relaxation. An amplifier solution is presented that predicts saturation effects in accord with experiments. Fabry-Perot oscillator solutions are also presented for a multiline saturated laser and a partly saturated single-line laser. The present results provide a basis for simplification of numerical codes. It is concluded that a reasonable first estimate for cw chemical laser performance can be obtained by assuming rotational equilibrium and translational nonequilibrium.
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Mirels