On These Disks, Storage Isn't Only Skin Deep
PEER DOWN INTO THE NEW CD-like disk developed at the State University of New York at Buffalo, and you can see Bugs Bunny up to his usual antics. What's so special about that? The disk doesn't spin steadily. Instead, the cartoon's successive frames are pulled from stacks of microscopic images extending deep inside the disk. Because these new optical disks store information in 100 or more layers, not just on the surface, they already hold up to 1 terabyte of data. That's 1 trillion characters, or 1,000 times as much as ordinary CDs.
The main secrets behind this three-dimensional trick are new dyes, for which the university is seeking patents, and a high-powered, pulsed infrared laser. Jayant B. Bhawalkar, an assistant professor at Buffalo's Photonics Research Laboratory, says the dyes respond only to the powerful infrared light. And because the beam is tightly focused at a precise distance, writing information on a specific layer--or retrieving it--is done by moving the laser up or down.
Although the laser's read/write head is similar to those in CD recorders, the pulsed laser is "currently very expensive," according to Bhawalkar. So don't look for consumer 3-D CDs anytime soon. Buffalo intends to license the technology after it receives a patent on the dyes. Because of the laser's cost, initial applications will probably be for archival storage of data and pictures at companies and libraries.