Considerations on holographic memories in the gigabyte region.

The capacity of conventional holographic memories is limited to about 10(8) bits. For use with computers, however, several orders of magnitude more are required. One solution is to store information in moving hologram tracks; this yields an order of magnitude more storage density. Alternatively, block-organized memories could be equipped with nonintegrated, large area detector arrays. This allows to reach 10(10) bits. Finally, we consider the hologram plate and its detector and page composer matrices as a compact storage module, and assemble many modules into a memory having one laser, deflector, and additional passive beam dividers. This allows random access to virtually unlimited capacities.