Economist.com | Holographic data storage: Review of issues and prospects for products in 2004; several write-once announced at 200-500 GB. "Theoretical calculations suggest that it will be possible to use holographic techniques to store a terabyte (1,000 gigabytes) of data on a CD-sized disk. Today's DVDs, by comparison, have a storage capacity of less than 20 gigabytes.
Moreover, holographic techniques permit the retrieval of data at speeds not possible with current storage methods. Transfer rates of a billion bits a second (at least 60 times faster than current DVDs) have already been demonstrated in the laboratory. Such fast access times are possible because the laser beams that are central to holographic technology can be moved rapidly, without inertia, unlike the components of a conventional disk drive. .. The challenge is to find the right recording material—a photosensitive substance that is both stable and cheap enough to use commercially. ..
searching a holographic store for a specific set of data is simple. Just as shining the appropriate reference beam produces a replica of the original data beam, so shining the appropriate data beam produces a replica of the reference beam. A beam that carries part of the original data will produce a weaker replica reference beam, making it possible to locate all the files that contain a particular set of data by shining in a beam containing that set and looking at the reference beams that come out. The intensity of each emergent beam indicates the degree to which the data stored in the file producing it match the target. Somebody sifting through a huge database could thus be directed rapidly to the best matches. With the growing commercial interest in data-mining—which involves sifting through vast amounts of information in order to find useful relationships—this aspect of holographic memory is extremely attractive. " 2:08:55 PM