Kinetic modeling of CW CO electric-discharge lasers

A rate equation analysis of convective CO electric-discharge lasers (EDL's) is presented. The spatial distribution of CO vibrational levels is governed by a kinetic master equation which contains terms representing electron impact pumping, vibration-vibration (VV) and vibration-translation (VT) energy transfer, and spontaneous and stimulated emission. Electronic pumping rates are derived from the solution to the electron Boltzmann equation. Spectral distributions of small-signal gain and optical flux are calculated in terms of the cross sections for these processes. Good agreement is obtained between predicted and experimentally reported gain and power spectra. For coincident discharge/cavity configurations, the quasi-steady small-signal gain is predicted to have a strong dependence on translational temperature for representative operating conditions. The predicted power output for a wide variety of bulk gas and plasma properties is found to be correlated by a simple energy-time parameter. The performance of other devices which involve separate discharge and cavity regions is also examined. The importance of the threshold excitation energy in understanding a variety of configurations is discussed.