Abstract

Much recent activity has focused on spontaneous spatial-pattern formation in nonlinear optical systems with feedback,^1,2 with most of these systems involving the use of a Kerr-like nonlinearity. Recent work by Grynberg et al. has shown spatial-pattern formation by using a saturable nonlinearity in rubidium vapor in which they observe high-order-mode formation of the Laguerre- Gaussian type. These modes have the appearance of a multipetaled flower and are different in spatial form from patterns normally observed in Kerr-like systems. In our work we show experimentally that flow- erlike-pattern formation also occurs in a laser resonator in which the saturable gain nonlinearity of the laser amplifier induces gain-grating formation that acts as a nonlinear diffractive feedback mechanism.

© 1995 Optical Society of America