Spatial dark-soliton stripes and grids in self-defocusing materials

Spatial dark-soliton (SDS) stripes are experimentally found in the transverse plane of a laser beam that passes through a rectilinear diffraction screen before propagating in a self-defocusing nonlinear material. Materials with different mechanisms of nonlinearity manifest the same qualitative results. The SDS nature of the observed phenomenon is verified by numerical simulations of the (2+1)-D nonlinear Schr\"odinger equation, analytical solutions for the (1+1)-D case, and their comparison with experimental data.