Optical dispersive shock waves in defocusing colloidal media

The propagation of an optical dispersive shock wave, generated from a jump discontinuity in lightintensity, in a defocusing colloidal medium is analysed. The equations governing nonlinear lightpropagation in a colloidal medium consist of a nonlinear Schrödinger equation for the beam and analgebraic equation for the medium response. In the limit of low light intensity, these equations reduce to aperturbed higher order nonlinear Schrödinger equation. Solutions for the leading and trailing edges of thecolloidal dispersive shock wave are found using modulation theory. This is done for both the perturbednonlinear Schrödinger equation and the full colloid equations for arbitrary light intensity. These resultsare compared with numerical solutions of the colloid equations.