Transport-induced-grating interferometry: application to photorefractive Bi12TiO20

Abstract

We have developed a technique to measure interferometrically charge-transport-induced refractive index gratings in photoconductive insulators. All four parameters needed to describe fully the interaction between the two beams Bragg matched to the grating can be determined. We use the method to find that the complex optical polarizability of an occupied charge trap equals that of an unoccupied trap plus (0.7 − i4.5 ± 0.7 ± i0.4) × 10−22 cm3 in photorefractive Bi12TiO20.