Ruggedized digital holographic data storage with fast access

Recent investigations in holographic mass memory systems have produced proo f-of-concept demonstrations that have highlighted their potential for provi ding unprecedented capacity, data transfer rates and fast random access per formance (Heanue at al. 1994; Hong et al. 1995; Psaltis and Mok 1995; Berna l et al. 1996; McMichael et al. 1996). The exploratory nature of most such investigations has been largely confined to benchtop experiments which have ignored the practical constraints of packaging and environmental concerns. We have embarked on an effort to demonstrate the holographic mass memory c oncept by developing a compact prototype system geared for avionics and sim ilar applications which demand the following features (mostly interdependen t factors): (1) solid state design (no moving parts), (2) fast data seek ti me, (3) robust with respect to environmental factors (temperature, vibratio n, shock). In this paper, we report on the development and demonstration of two systems, one with 100 MB and the other with more than 1 GB of storage capacity. Both systems feature solid state design with the addressing mecha nism realized with acoustooptic deflectors that are capable of better than 50 mu sec data seek time. Since the basic designs for the two systems are s imilar, we describe only the larger system in detail. The operation of the smaller system has been demonstrated in various environments including hand -held operation and thermal/mechanical shock; a photograph of the smaller s ystem is provided, as well as actual digital data retrieved from the same s ystem.