title: Model of anisotropic nonlinearity in self-defocusing photorefractive media.
abstract: We develop a phenomenological model of anisotropy in self-defocusing photorefractive crystals. In addition to an independent term due to nonlinear susceptibility, we introduce a nonlinear, non-separable correction to the spectral diffraction operator. The model successfully describes the crossover between photovoltaic and photorefractive responses and the spatially dispersive shock wave behavior of a nonlinearly spreading Gaussian input beam. It should prove useful for characterizing internal charge dynamics in complex materials and for accurate image reconstruction through nonlinear media.
authors.forename: C
authors.initials: C
authors.lastname: Barsi
authors.forename: J W
authors.initials: JW
authors.lastname: Fleischer