Chaotic and hexagonal spontaneous pattern formation in the cross section of a laser beam in a defocusing Kerr-like film with single feedback mirror

We present a comparative experimental study on the spontaneous formation of patterns in the transverse cross-section of a laser beam traversing a thin slice of self-focusing and self-defocusing Kerr-like media in the one feedback mirror arrangement. In both cases, at critical laser intensity, hexagon to chaotic pattern transition was observed. (C) 1997 Elsevier Science B.V.