Influence of a Time-Dependent Applied Electric Field on the Photocurrent in Photorefractive Materials

From the differential material rate equations, we found an additional term to the usual expression of the photocurrent, which appears only when a time-dependent external electric field is applied. This term influences the photocurrent in the material. We applied our equations to a Bi12SiO20 sample, under an applied sinusoidal electric field. This sample is illuminated with an oscillating interference pattern formed by two plane light waves, one of which is phase-modulated with frequency ω. We found good agreement with experimental results. Besides, for this case, our prediction for the photocurrent is better than the usual prediction of the photocurrent for low values of ω.