Delayed polarization dynamics inNd3+-doped yttrium-aluminum-garnet lasers

Abstract

The response of a ${\text{Nd}}^{3+}$-doped yttrium-aluminum-garnet laser is examined experimentally when the pump polarization direction is abruptly changed from one to the other stress-induced principal axis of the cavity. As a result, the laser output polarization changes direction but only after a significant delay. We numerically solve rate equations that describe the evolution of the two polarization fields coupled to the population inversion. The simulations indicate that the polarization switching (PS) delay depends on two successive processes that we analyze using multi-time-scale techniques. The analysis predicts two qualitatively different PS responses depending on how close the laser is from its threshold. Finally, we compare quantitatively the experimental and theoretical estimates of the PS delay.