Abstract

Pattern formation in optical cavities has been studied since lasers were discovered [1]. Patterns start forming when particular frequencies are selected from noise, because they experience higher gain, and, through the cavity feedback, stabilize to form a pattern. Examples include the formation of stripes, hexagons, spirals, vortices, shock waves, complex ring, and lattice-like features [for a review see Ref.[2]]. These phenomena were observed in a variety of materials: laser gain media, photorefractive crystals, thermal nonlinearities, quadratic nonlinearities, and more [3]. What signifies cavity effects from one-way propagation, is the existence of a threshold for pattern formation and the existence of resonant frequencies. In cavities, pattern formation exhibits different features below and above a specific threshold. In coherent cavities, the patterns are also highly affected by the detuning between the frequency of the light beam and the nearest resonant frequency of the cavity. However, for all of the resonators studied previously, pattern formation is a spatially and temporary coherent process, that is, the coherence length of the light is much larger than the cavity length.

© 2002 Optical Society of America