Holograms Head For The Trenches
THE COLD WAR IS OVER, BUT THE MILITARY STILL CRAVES whiz-bang technology. To win future wars, reasons the Defense Dept.'s Advanced Research Projects Agency, soldiers will need lightning-fast access to oceans of data and digital images. So ARPA is picking up half of the $32 million tab for a five-year research program to commercialize a holographic data storage system (HDSS).
Drawing together researchers at Stanford University, IBM, GTE, Rockwell, and other companies, the HDSS consortium is using lasers and other electro-optic components to create two-dimensional patterns--called "pages"--of light and dark regions representing digital bits. These are recorded in light-sensitive crystals as holograms. Thousands of pages representing billions of bits can be stored in the crystal (photo). And each page can be recovered by illuminating the crystal with the unique reference beam that was used to record that page. A gigabyte of data that fits on today's disk drives could be crunched into a space the size of a pencil eraser. And data could be transported in and out of the crystals at a rate of 1 billion bits per second, or about 10 times the speed of today's drives. The consortium hopes to have a prototype for write-once recording in three years.