MONOTONIC VERSUS OSCILLATORY BEHAVIOR DURING HOLOGRAPHIC WRITING IN PHOTOREFRACTIVE PHOTOVOLTAIC MATERIALS

An analytical time-dependent solution for the light-induced first-harmonic holographic grating has been obtained for photorefractive materials presenting a bulk photovoltaic (PV) effect. The corresponding expression for this PV drift explicitly includes the active donor concentration. From that solution, the role of the physicochemical state of the material (total impurity concentration and reduction state) on the occurrence of transient and oscillatory behaviour during grating formation in LiNbO3 has been analyzed in detail and compared to available experiments. © 1990.