SELF-INDUCED MODE AS A BUILDING ELEMENT OF TRANSVERSAL PATTERN-FORMATION

Optical patterns, forming in transversely extended nonlinear feedback systems, sometimes consist of ordered or disordered arrangements of ma ny bright circular spots. We derive an approximate analytical descript ion for a localized individual spot for the case of a diffusive Kerr n onlinearity. Each spot represents a Gaussian mode, which induces its o wn spherical subresonator by supporting a nonlinear lens in the Kerr m edium. The properties of these self-induced modes are related to syste m parameters and their multistable behaviour is investigated. Interact ion between two or more spots is estimated, leading to an easy explana tion of hexagonal pattern formation.