Optical switch using the photorefractive effect and ferroelectric polarization reversal

Abstract

A new form of optical switching in photorefractive ferroelectric materials is described. Ferroelectric polarization reversal is used to reverse the c axis and, consequently, the direction of nonlinear gain in a photorefractive barium titanate crystal. We report optical switching in 100 microsec with a 60-to-1 on-off ratio when this technique is used. Onoff ratios of 500 to 1 are predicted for typical crystals with gain-length products of 4.