Optimization of laser intracavity second-harmonic generation by a linear dispersion element

Changing the relative phase Delta phi between the fundamental and harmonic waves produces periodic power modulation of a laser intracavity second-harm onic generated wave. The periodic power modulations of the two counterpropa gating second-harmonic waves are at exactly opposite phases. This behavior is different from that in the case of intracavity second-harmonic generatio n in a passive cavity. A phenomenological numerical model developed for a l aser consists of double-pass second-harmonic generation. The steady-state p lane-wave model incorporates second-order nonlinear interaction, laser gain , and linear dispersion that contribute to the phase difference Delta phi. The model predictions are in good agreement with the experimental results. The model is useful for optimization of laser intracavity second-harmonic g eneration, and it may be applied to different types of intracavity nonlinea r interaction. (C) 1999 Optical Society of America [S0740-3224(99)02010-X].