Abstract

Dark soliton stripes (DSS’s) and grids were recently discovered in the cross-section of a laser beam [1] which propagates through a self-defocusing medium. Now we find that a dark soliton stripe can spawn optical vortex pairs of opposite topological charge when subjected to transverse modulations whose period exceeds the soliton size. We have also observed vortices even when solitons are not allowed. This phenomenon can be described by the nonlinear Schrödinger equation (NLS), which also describes vortices in superfluids. To our knowledge, these are the first observations of stationary vortices in a single pass nonlinear optical system.

© 1992 Optical Society of America