Traditionally, a DVD is written by using a lens to focus laser light. The thinner the beam, the more information the laser can etch on the disc. For years, scientists have manipulated the lens to narrow the beam, reaching a minimum of 405 billionths of a meter. The Harvard team takes a new path that does not use a lens. Instead, they place two tiny gold rods on the end of the laser, creating an antennalike device. When the light passes through the antenna, it causes the electrons in the gold to move quickly, creating an electric field that concentrates the beam to a point just 40 billionths of a meter wide.
The Harvard researchers expect the first applications to be in CDs and DVDs, and believe the idea could be used to expand the capacity of everything from digital cameras to MP3 players. They say Hitachi and Seagate have already shown interest in using the technology for data storage. But a real-life superdisc is roughly 10 years from reaching the consumer market. So don’t throw away that DVD rack just yet.
