Dark and bright vector spatial solitons in biased photorefractive media

We show that the vector beam evolution equations in properly oriented biased photorefractive media can exhibit bright-dark soliton pair solutions under steady-state conditions. These wave pairs are obtained perturbatively provided that the intensities of the two optical beams are approximately equal. Our analysis indicates that these bright-dark vector solitons exist irrespective of the polarity of the external bias field. The stability of these vector pairs has been investigated numerically and it has been found that they are stable only in the regime of positive bias polarity.