Vector analysis of the space-charge field in nonconventionally biased photorefractive crystals

A theoretical model to numerically study the local space-charge field induced by light in a photorefractive crystal biased with two independent, perpendicularly oriented external static fields is introduced. This model appears attractive because it allows varying, in the crystal transverse plane, of the orientation of the external biasing static field with respect to that of the optical-field vector, then enhancing the tensorial properties of the crystal. The numerical analysis has revealed that, in a nonconventional biasing configuration, the spatial distributions of the space-charge-field vector transversal components exhibit a further anisotropy that has not been shown up to now. Nevertheless, from a practical point of view, such a boundary configuration could allow better management of the focusing characteristics of the material.