Counterpropagating beams in rotationally symmetric photonic lattices

Various properties of counterpropagating mutually incoherent self-trapped beams in optically induced circular photonic lattices with ring defects are investigated numerically. We utilize a local isotropic dynamical model with a Kerr-type saturable nonlinearity. Different incident beam structures are considered. We find spontaneous symmetry breaking of the head-on propagating Gaussian beams. In the case of vortices, we observe beam filamentation and a strong pinning of filaments to the lattice sites. Using a modified Petviashvili's method, we report several novel solitonic structures. (c) 2007 Elsevier B.V. All rights reserved.