QUANTUM-MECHANICAL DIFFUSION OF THE POLARIZATION OF A LASER

We have observed the influence of spontaneous emission on the polariza tion of a miniature HeXe laser (lambda = 3.51 mu m). The situation whe re the quantum noise dominates over cavity anisotropies is realized an d we demonstrate that this leads to quantum mechanical diffusion of th e polarization. Since our laser operates in the bad-cavity regime, the polarization diffusion is slowed down by a memory effect of the gain medium.