Theoretical analysis of the photocurrent dark decay in photorefractive media

The photocurrent dark decay in photorefractive materials is theoretically analyzed by using two different dynamical approaches-namely, the shallow traps and electron-hole transport models. The analysis is based on experimental results that show a double exponential decay of the photocurrent with short pulsed or continuous excitation. Expressions for the photocurrent amplitudes and decay times have been derived in terms of material and excitation parameters. Several dynamic behaviors are predicted for both models.