Scanning tunneling microscopes (STMs), invented in 1981, let scientists rearrange atoms on a substrate. By the late 1980s, some labs were lining up atoms to spell out corporate logos. For the Japanese, it was more than a frivolous exercise: In March, collaborators at the University of Osaka Prefecture and Ion Engineering Research Institute Corp. in Osaka demonstrated that STMs could create a new recording technology that packs up to three hours of color motion pictures on a device the size of a credit card.
The STMs open up tiny holes on an arsenic-selenide film deposited on graphite. A separate probe interprets the presence or absence of the holes as digital sequences of zeros and ones that a computer can translate as data, music, or images. Since the holes are far smaller than the pits on audio CDs and CD-ROM disks--just 79 billionths of an inch--more information can be crammed in a smaller space. The researchers aim to have a prototype by mid-decade.