Prolonged readout using two-defect species in SBN

Summary form only given. Holographic data storage offers various advantages, such as high storage density and rapid transfer rates, and short access time. An essential criterion for this method to be practical is the ability to retain information after many readout cycles. Several fixing techniques have been investigated, including thermal fixing, electric fixing, two-photon recording; and multiple species participating in grating formation in photorefractive crystals. Because of its high sensitivity and strong electro-optic coefficient, SBN is an important candidate for holographic storage medium. Recently, increase of absorption attributed to a two species system at longer wavelengths after illumination of green light in SBN was discovered. We report here new evidence of prolonged readout involving two species in SBN, which results in prolonged readout of holographic gratings. Experiments are performed on an SBN crystal using a dye laser tuned to 602 nm. Grating buildup and erasure behaviors were studied with external incident angles ranging from 200 and 600, and an average power of 30 mW in each writing beam in a standard transmission recording geometry.