Long-term continuous readout of a photorefractive memory with BaTiO(3) postamplification

We propose and demonstrate a long-term readout photorefractive memory. It is made up of two photorefractive crystals: the first where the images are stored and the second where the signal is amplified by use of a low-noise self-bent pump-beam technique, making it possible to use very low illumination of the storage crystal. A LiNbO(3)/BaTiO(3) configuration is used with angular multiplexing; this technique permits continuous readout for more than 60 days. The long-term storage capacity and the maximum number of stored images are estimated.