Effect of a photovoltaic field on the Bragg condition in LiNbO_3

摘要

We report experimental and theoretical studies of the electric field shift in the position of the diffraction efficiency maximum for holograms recorded in LiNbO_3. The homogeneous field results from compensation of the photovoltaic current by the conductivity current, and it can be up to 7 kV/cm. This field can change the average refractive index of the crystal and thus affects the Bragg condition during hologram recording and reconstruction. We demonstrate the electric field shift phenomenon for the holograms multiplexing. To realize the proposed mode of multiplexing one has to vary only recording time and recording intensity.