Abstract

Structure formation, symmetry breaking, and optical vortices are typical spatial phenomena in NLO feedback systems, which have found growing interest in the last decade. The system we investigate consists of a Fabry–Perot resonator with planar mirrors spaced from 50 μm to some centimeters and an intracavity NLC film as an optically nonlinear medium. In our studies we use the optically induced reorientation of the molecules as the optical nonlinearity. As long as the diameter of the input beam does not exceed the spatial resolution of the NLC we observe optical bistability. Using larger beam sizes leads to complex dynamic behavior accompanied by the formation of spatial structures with broken symmetry. The Gaussian input beam decays into a number of spots with a certain diameter trying to form a maximum packing density inside the illuminated area. Observing the phase of transmitted light holographically, we found phase singularities (from their helixlike structure) in the area between such spots. It seems that the appearance of these phase singularities are concomitant phenomena of competition effects between neighboring spots during the self-organizing process of structure formation.

© 1992 Optical Society of America