The saturation irradiance and line-shape parameters of a high-gain laser transition are determined by analyzing the measured gain of a gas-laser amplifier as a function of incident radiation, based on a quadratic approximation to the saturated gain. Experimental results for a high-gain xenon 3.5 µm (5d33-6p22) laser amplifier are presented.
Hideya Gamo and John S. Ostrem, "Determination of laser parameters from saturated-gain measurements for a partially homogeneously broadened gas-laser amplifier," J. Opt. Soc. Am. 65, 29-32 (1975)