Kinetics for optical erasure of sinusoidal holographic gratings in photorefractive materials

The kinetics of erasure of sinusoidal holographic gratings in photorefractive materials has been investigated. A general solution applying to arbitrary transport lengths in comparison to the grating period has been obtained. The proposed method permits a good insight into the involved physical mechanism and reveals some interesting features of the general solution such as the constant dephasage between the donor and carrier gratings. On the other hand, it can account for the role of the oxidation/reduction state of the sample, which very markedly influences the kinetic behavior. In particular, it has been shown that the short transport length approximation rapidly loses its validity with the level of reduction. The model has been applied to LiNbO
3
and used to discuss some recent experimental erasure data obtained by Tyminski and Powell.