Transient Photorefractive Effect in Graded Gap Superlattices

Abstract

We report a new type of photorefractive effect which does not rely on traps, requires only a single illumination beam and is inherently fast The effect is efficient enough to cause significant polarization rotation of a probe beam via the electro-optic effect, using only a short (2µm) interaction length. Furthermore, the temporal response can be easily controlled by changing either the intrinsic or photo-induced carrier density. The effect can also be used to examine the transport of free carriers in graded gap structures.