Low-amplitude screening-photovoltaic spatial solitons in two-photon photorefractive media

In order to obtain low-amplitude two-photon screening-photovohaic spatial solitons,low-amplitude spatial solitons in biased two-photon photovohaie photorefractive crystals were studied.Then,the analytical expressions for both the bright and dark low-amplitude two-photon sereening-photovoltaic spatial solitons in photorefractive crystals were obtained.The explicit expressions for the width of these spatial solitons were deduced.The result shows that the low-amplitude two-photon screeningphotovoltaic solitons can be considered as the united form of screening solitons and photovohaic solitons.They reduce to screening soliton in the absence of photovoltaic effect,whereas they become photovoltaie solitons under the open or closed circuit condition when the bias field is not applied.It turned out that this research provides theoretic basis for development of the spatial solitons theory.