Selective erasure of holographic index gratings in photorefractive crystals

We proposed a novel method to realize selective erasure of holographic index gratings in the photorefractive crystals. This scheme is based on the self-enhancement of the index gratings in the photorefractive materials. It is a save-erase-restore procedure, namely, save wanted information-erase unwanted information-restore wanted information. Simple experimental results are also presented. The requirement in this scheme is that the material has the effect of self-enhancement, i.e. the index grating is transmission grating, the product of the coupling constant and the thickness is above the threshold of the self-enhancement. But it eliminates the critical requirement of preventing vibration in the previous pi-phase-shift scheme.