INCOHERENTLY COUPLED SCREENING-PHOTOVOLTAIC SPATIAL SOLITON PAIRS IN BIASED TWO-PHOTON PHOTOVOLTAIC PHOTOREFRACTIVE CRYSTALS

The incoherently coupled dark-dark, bright-bright, bright-dark screening-photovoltaic spatial soliton pairs are predicted in biased two-photon photovoltaic-photorefractive crystals under steady-state conditions. The result shows that these soliton pairs are established by the solitary beams which have the same polarization, wavelength, and are mutually incoherent. The screening-photovoltaic soliton pairs can be considered as the united form of screening soliton pairs and open or closed-circuit photovoltaic soliton pairs. They reduce to screening soliton pairs in the absence of photovoltaic effect, whereas they become photovoltaic soliton pairs under the open or closed-circuit conditions when the bias field is not applied. Moreover, the stability of these solitons has been investigated.