A conventional DVD stores data only on its surface. But holographic storage encodes data as three-dimensional patterns embedded inside a disc, vastly expanding its storage capacity. A long-awaited holographic drive from InPhase of Longmont, CO, is due out late this year; geared to Hollywood studios and large archives, it will cost $18,000. But a few companies, such as General Electric and Sony, are working on holographic storage systems that could be more compatible with existing technologies.
InPhase’s drive stores information in big blasts, 1.4 million bits at a time. That makes data retrieval extremely fast, but it also requires complicated and costly optics. A prototype system from GE, on the other hand, stores information a bit at a time–just like today’s media. That means that GE’s holographic discs could be played on modified Blu-ray players, which could potentially handle old DVDs and CDs, as well.
In the GE technology, the holographic bits–each measuring 0.3 by 5 micrometers–are arrayed in a plane, with dozens of planes layered throughout the disc. Initial versions of the disc will hold 300 gigabytes of data–about six times as much as a Blu-ray disc–and might reach market by 2012. Brian Lawrence, manager of GE’s Optical Polymer Lab, says that the technology should ultimately let a disc the size of a DVD store a terabyte of data. GE faces plenty of competition, however. Besides InPhase and Sony, other companies working on holographic storage include Daewoo and Maxell.
The experimental setup includes a beam splitter (cube at left) that bounces one of the beams off of a mirror (not shown) to ensure that it travels the same distance as the other beam before striking the disc.
Courtesy of General Electric