LOCALIZED STRUCTURES IN CHAOTIC PATTERNS - FROM DISORDER TO ORDERING

Two-dimensional (2D) ''chaotic'' localized structures are observed in the transverse profile of light with a delay model of a ring cavity wi th strongly dispersive two-level atoms. Near nascent optical bistabili ty, the 2D homogeneous solution undergoes a subcritical transition to a spatiotemporal chaos. The inhomogeneous pattern coexisting with the homogeneous solution is filled with large-intensity peaks, oscillating with time. In the subcritical domain, localized structures are observ ed, with isolated peaks more stable and more coherent than the ones in the filled structure. The order is easily recovered by a filtering pr ocedure that reduces the wavevector bandwidth.