Higher-order space charge field effects on the evolution of spatial solitons in biased photorefractive crystals

Summary form only given. Recently, photorefractive (PR) spatial optical solitons have been the focus of considerable attention. Of particular interest are the so-called screening solitons that occur in steady state when an external bias voltage is appropriately applied to a PR crystal. These soliton states are known to occur when the drift term dominates in the expression of the space charge field. In a recent study, the effects arising from first-order diffusion terms have also been investigated. It was found that the PR soliton can experience adiabatically self-deflection that varies linearly with the applied electric field. However, recent experiments suggest that this self-deflection can exceed that predicted by theory, especially in the regime of quite high bias fields. To account for this discrepancy, we investigate the effects of other higher-order electric field terms on the evolution of bright steady-state solitons in PR media.