The use of holography is attractive for optical data storage due to its potential for implementing page oriented data storage systems. However, multiplexed recording using Bragg selective materials has not provided a large enough storage capability to justify the expense of these systems. Persistent spectral hole burning holography allows multiplexed recording using much smaller wavelength separations between the holograms, and hence dramatically increases the storage capacity possible in holographic memory systems [1]. A comparison between the wavelength selectivity obtained for transmission gratings recorded using hole burning in a dye doped polymer film versus Bragg selectivity in a 1 cm thick iron-doped lithium niobate crystal is shown in Fig. (1).
An optical storage technique based on time-domain holography for the rapid recording and readout of page-formatted digital data is demonstrated. Storage of 356 kilobits of data was achieved at a single spatial location in a rare-earth–doped crystal. The digital data were recorded and accurately retrieved at a peak rate of 300 megabits per second without the use of error-correcting codes. The system's raw bit error rate is about 10 − 7 . This low bit error rate was achieved by a detection scheme for extraction of binary data. These results have implications for dynamic optical memory.