Abstract

We describe an angularly and spatially multiplexed holographic memory that is arranged in a disk format. The memory is constructed with a z-cut lithium niobate disk 1.5 in. in diameter and 5 mm thick. Holograms are stored in multiple locations, each location being roughly 2 mm by 2 mm. Up to 1,000 angular multiplexed holograms can be recorded at each location, and 20 locations can be recorded on the disk. Individual holograms recorded on the same location are accessed by changing the reference beam angle, and different locations on the disk are accessed by rotating the crystal. In our demonstration, we recorded 100 holograms per location and stored approximately 3 min of a movie on the crystal. The individual video frames were recorded as reflection type holograms. We discuss the advantages of this geometry in terms of diffraction efficiency and uniformity of diffraction efficiency with respect to disk rotation and change in reference beam angle. Other possible geometries will also be discussed.

© 1992 Optical Society of America