Abstract

Although complicated light field structures appeared in recent experiments with nonlinear optical systems, the patterns observed so far could be interpreted either as transverse modes of the resonator, or as the simultaneous excitation of many transverse modes. This implies that the patterns were dominated by boundary effects, rather than by the nonlinearity of the medium. The active nonlinear systems, like lasers, could not maintain an arbitrary image in their radiation, nor to display the „ essentially nonlinear“ patterns. „Essentially nonlinear“ pattern formation of lasers as it is described by the complex Swift-Hohenberg equation [1], requires primarily a large Fresnel number of the resonator and simultaneously a high level of degeneracy of transverse mode families.

© 1998 IEEE