External field-controlled photovoltaic symbiotic spatial soliton pairs in two-photon photorefractive crystals

We report the existence of incoherently coupled bright-bright steady state photovoltaic (PV) soliton pairs in biased two-photon photorefractive (TPPR) materials that arise due to the TPPR effect. A remarkable finding is that, with the application of electric field, it is possible to generate solitons and control them in such media, where soliton formation was actually prohibited hitherto. The present analysis indicates the existence of a plethora of bright-bright soliton pairs with dynamical properties controllable by the application of an external electric field of appropriate polarity and magnitude. We have identified two different power regimes in which the effect of external electric field is opposite. We have undertaken linear stability analysis which shows that these solitons are stable.