Abstract

Most solid-state lasers are described by the Tang, Statz and deMars rate equations [1] that couple the modal intensities to the population inversion. We consider the response of such lasers to weak perturbations. This covers the relaxation to steady state after the abrupt modification of a laser parameter, the influence of noise and small amplitude modulation of a laser parameter. Typical laser parameters that are perturbed or modulated are the gain linear medium or the cavity losses. A useful way to characterize the response of these lasers is the modal and total intensity power spectra. Let P(j,Q) be the peak of the power spectrum of the modal intensity j at the frequency Ω and P(τ,Ω) the same for the total intensity. The following results are obtained analytically by determining the eigenvalues and eigenvectors of the evolution equations linearized around the exact steady state. All photon lifetimes are assumed to be equal. The small parameter for these lasers is δ, the ratio of the photon to population lifetimes that is typically of the order of 10⁻⁵. The relevant expansion parameter is the square root of δ.

© 1996 IEEE