Recently, the propagation of dark spatial solitons in a variety of different material systems has been observed by the PI. These systems include sodium vapor, various thermal liquids, and the bulk semiconductors ZnSe and GaAs. The work described in this proposal will consist of experimental, theoretical, and numerical efforts, and represents a comprehensive program designed to understand the fundamental nature of the propagation of dark spatial soliton eigenmodes in general self-defocusing nonlinear optical media. We will investigate in detail the collision and stability properties of these solitons when they are subjected to experimental perturbations. Such perturbations may include loss (both linear and nonlinear absorption), deviation from the simple Kerr-law dependence of the real part of the refractive index, and instabilities induced by the difference in dimensionality between the experimental situation and the one typically assumed for theoretical treatments of the problem. In addition to the experiments to be performed in bulk nonlinear optical media, a series of experiments designed to investigate the propagation characteristics of dark surface waves will be performed. Dark surface waves are a new kind of wave discovered by the PI which are closely related to dark spatial solitons and are expected to have application in the area of nonlinear integrated optics.
