Control of domain structures in lithium tantalate using interferometric optical patterning

We report a room temperature technique for periodically inverting the domai n structure in a lithium tantalate crystal, via the simultaneous applicatio n of optical and electric fields. Ultraviolet light from an Ar ion laser wa s incident on a 200-mu m-thick z-cut lithium tantalate crystal, illuminatin g the y-face which had been polished to form a biprism. The resulting inter ferometric pattern, formed between planar liquid electrodes applied to the +z- and -z-crystal faces, had a period of 6.3 mu m. We show the results of optical control of the poling process, and discuss the theory behind light- induced ferroelectric switching. (C) 1999 Elsevier Science B.V. All rights reserved.