Dynamic Stark effect in CH3F and other optically pumped lasers

The dynamic Stark effect in optically pumped lasers is discussed. Javan's theory of three-level masers is extended and elucidated by transforming his expressions into new forms in which all of the major terms can be deduced from a modified energy-level diagram through simple physical arguments. The gain spectra of high-power 496-μm CH
3
F lasers are calculated from the theory. Contrary to previous interpretations, the wide emission bandwidth at pump intensities above 30 kW/cm
²
is shown to be primarily due to the dynamic Stark effect on
K= 1, 2,
and 3 components. It is found that to obtain a narrow emission bandwidth the pump intensity should be kept below 10 kW/cm
²
.