Screening-photovoltaic spatial soliton in two-photon photorefractive media

In order to obtain a more perfect theory of two-photon screening-photovoltic solitons,the theory of spatial solitons in biased two-photon photovoltaic photorefractive crystals were amended theoretically under the condition that spatial width of the beam was not much smaller than the width of crystal.The numerical integral solutions for both the bright and dark solitons were presented.The result shows that different from screening solitons originating from the spatially nonuniform screening of the external electric field and photovoltaic solitons originating from the photovoltaic effect,two-photon screening photovoltaic solitons originates from both the spatially nonuniform screening of the external electric field and the photovoltaic effect.When the photovoltaic effect is neglected,the screening-photovoltaic solitons are the screening ones and their space charge field is the space charge field of the screening solitons.When the external field is absent,the screening photovoltaic solitons are the photovoltaic ones on the open and closed circuit conditions and their space charge field is of the photovoltaic solitons.