Optical nonlinearity and existence conditions for quasi-steady-state photorefractive solitons

Generalizing soliton description using spatiotemporal wave variables, we identify and experimentally validate the nordinearity supporting quasi-steady-state solitons in biased photorefractive crystals for the one-dimensional case, the transient counterpart of the explicit one-dimensional screening soliton theory. The approach leads to a non-Kerr-like spatially local exponential nonlinearity and explicitly provides soliton existence conditions. These find quantitative agreement with a series of experiments in potassium lithium tantalate niobate and reproduce previously described transient behavior. (c) 2006 Optical Society of America.