Determination of line-shape parameters of high-gain laser transitions based on line-narrowing measurements

Abstract

A new method for determining the Lorentzian linewidth, the Dopplerlinewidth, and the population inversion in high‐gain laser media, for which the signal‐to‐noise ratio is better than that of previous methods owing to superradiant amplification, has been developed. These parameters can be determined based upon the experimental measurement of spectral line narrowing, spontaneous emissionlinewidth, and small‐signal gain with the use of numerical tabulations of the spectral line‐narrowing coefficient and the ratio of spontaneous to Dopplerlinewidths. In case either the spontaneous linewidth or the small‐signal gain is not available, the same parameters can be determined by doing a curve fit to the spectral line‐narrowing data. The superradiant radiation output of the xenon 3.5‐μm line is analyzed by the latter method.