Interplay of linear and nonlinear effects in the formation of optical vortices in a nonlinear resonator.

Abstract

We study the role played by nonlinearities in the formation of optical vortices when the boundary conditions determine the pattern formation in a Fabry-P\'erot resonator. Particular care is taken to avoid trivial vortices coming from particular Gaussian modes or from the cavity alignment. We show that, while the existence of optical vortices is a generic linear property of the superpositions of Gaussian modes, their actual appearance in the transmitted patterns is controlled by the nonlinearity itself.