The isotropic nature of photorefractive screening solitons and the interactions between them

Summary form only given. Studies on the incoherent and coherent collisions between photorefractive screening solitons in both one and two transverse dimensions have been reported recently. These studies report on the fusing and repulsion of coherent solitons, as well as on the birth of additional solitons. Interestingly, these studies have been able to ignore the role of the two-dimensional anisotropic nature of the photorefractive material. In this paper we present experimental evidence demonstrating that the photorefractive-index perturbation responsible for the formation of individual photorefractive screening solitons and the behavior of coherent collisions between them is isotropic, even though the photorefractive medium is inherently anisotropic. The evidence is based on three independent observations.