Improved electro-optic materials and fixing techniques for holographic recording

This paper describes recent improvements in materials and techniques for storage of high efficiency phase holograms in electrooptic crystals. The storage performance of lithium niobate and barium sodium niobate was greatly enhanced by introducing transition metal impurities or by subjecting the undoped crystals to irradiation treatments. The latest materials combine good sensitivity with diffraction efficiencies that reach well over 50% for sample thickness of a few millimeters. In addition, the fixing techniques that were developed offer a simple means of achieving nondestructive readout for holographic information stored in these crystals.