Untangling the data traffic jam.

Anyone who ever has waited impatiently for a personal computer to close a document or spreadsheet is familiar with the bottleneck. it doesn't matter how much information the PC can handle, it has to store and retrieve it one bit at a time. Even for the fastest computers, getting data in and out of stored memory is as slow as the spin of a disk.

Since the 1970s, scientists have envisioned storing that spreadsheet all at once, with laser holography. In a single flash of laser light, the image of an entire page would be stored as a hologram, 100 to 1,000 times faster than now. Until recently, this idea was hampered by a problem with the large crystals used to store the holograms. When data is retrieved, scattered light mixes up information from more than one page at a time.

Lambertus Hesselink, a Stanford University professor of electrical engineering and aeronautics/astronautics, has come up with a solution that allows laser optics to store numerous holograms in a single crystal rod smaller than a pin. The rod is too small for "crosstalk" between images. Each hologram contains 100,000 to 1,000,000 bits of data, stored in the rod - also called an optical fiber - using two beams of laser light. An object beam is bounced off the image to be recorded - a spreadsheet, for example - and then into the fiber. A reference beam crosses the object beam and records the image in the fiber as a pattern of electrons. Each reference beam is encoded so that, bounced into the fiber again, it retrieves only the pattern for the particular page that it...