Incoherently coupled bright-dark screening-photovoltaic soliton pairs in two-photon photorefractive media

The incoherent coupling of two mutually incoherent optical beams with the same polarization and wavelength in biased two-photon photovoltaic photorefractive crystals was investigated. The condition which is needed for producing two-photon incoherent coupled bright-dark screeningphotovoltaic soliton pairs is presented in the paper. Taking Cu:KNSBN crystal as a research object, the light intensity spatial distribution of twosoliton components of incoherently coupled bright-dark screening-photovoltaic soliton pairs in two-photon photorefractive crystal is given while =117.3,=83.79,=1.510-4，=104，=0.005，r=10 is selected. The research verified that there are incoherently-coupled bright-dark screeningphotovoltaic soliton pairs in the two-photon photovoltaic photorefractive crystal that has applied electric field. It is pointed out that the soliton pairs are formed by two incoherent beams which have same polarization state and wavelength.