Abstract

Spatial dark solitons (SDS) are self-guiding "shadows" which exist as dark stripes or grids in the cross-section of a laser beam that propagates through a self-defocusing nonlinear material (n₂ < 0).¹ They are stable in not only 2-D waveguides, but also in bulk 3-D configurations, which opens the possibility of 3-D nonlinear devices based on SDS.² Novel approaches to nonlinear optical engineering are possible by taking advantage of the formation and interaction of these fundamental nonlinear modes. Our experimental observations of SDS in bulk nonlinear materials have demonstrated that this phenomenon can be easily observed by passing a Gaussian laser beam through a rectilinear amplitude and/or phase diffraction mask placed at the input face of the nonlinear material. (See Fig. 1.) The large amplitude fluctuations of the diffracting radiation near the mask gives rise to the formation of dark soliton stripes.

© 1991 Optical Society of America