Spatial rectification of the electric field of space charge waves

A new phenomenon associated with a nonlinear interaction of optically excit ed space charge waves has been discovered in photorefractive crystals of th e sillenite family. This interaction provides a spatial rectification of th e electric field of the space charge waves and leads to a temporally oscill ating, but spatially homogeneous electric field of the order of 50-60 V/cm which is detected by a probe beam via the electro-optic effect. Taking into account that the displacement current plays an important role, we demonstr ate a very good agreement between the experimental data and the suggested t heoretical model.