Dispersion in a laser-pumped molecular laser

The dispersion equations are derived for two laser fields of arbitrary intensity interacting with a homogeneously broadened, three-level molecular system. The results obtained apply to laser-pumped molecular lasers and may be used to analyze frequency pulling of the emitting laser and self-focusing or defocusing of the pump laser. The laser fields are allowed to be of arbitrary intensity and to be on or off resonance. The dispersion function for the emitting laser
\chi'(\omega_{s})
is evaluated in various limits. The present theory is applied to analyze previous experimental data for cavity frequency pulling in CO
2
laser-pumped molecular lasers, including a 385-μm D
2
O laser and a 496-μm CH
3
F laser. Good agreement is found between theory and experiment.