Observations of anomalous gain coefficients in TEA double-discharge CO2lasers

Direct measurements of the gain coefficient of a TEA double-discharge CO
2
laser versus wavelength show that while the overall wavelength dependence is in good agreement with that predicted from the model wherein the rotational levels are in thermal equilibrium,
P(20)
in the 10.4-μm band and
P(22)
in the 9.4-μm band have a gain coefficient that is ∼10-percent high. These results are interpreted as evidence for stimulated emission from "hot bands" by these laser lines. Other transitions in these two bands should also exhibit gain coefficients that have been enhanced to a lesser degree.