Storing data in 1,000 points of light.Storing data in 1,000 points of lightWn chemist Tuan Vo-Dinh of Oak Ridge Oak Ridge, city (1990 pop. 27,310), Anderson and Roane counties, E Tenn., on Black Oak Ridge and the Clinch River; founded by the U.S. government 1942, inc. as an independent city 1959. (Tenn.) National Laboratory began work on a new soil analysis system for the Environmental Protection Agency Environmental Protection Agency (EPA), independent agency of the U.S. government, with headquarters in Washington, D.C. It was established in 1970 to reduce and control air and water pollution, noise pollution, and radiation and to ensure the safe handling and , he had no idea that the underlying principle, known as Raman scattering Raman scattering or the Raman effect is the inelastic scattering of a photon. When light is scattered from an atom or molecule, most photons are elastically scattered (Rayleigh scattering). , held potential for an innovative optical data storage technology. Typical compact disks store a binary code binary code Code used in digital computers, based on a binary number system in which there are only two possible states, off and on, usually symbolized by 0 and 1. Whereas in a decimal system, which employs 10 digits, each digit position represents a power of 10 (100, 1,000, of ones and zeros Ones and Zeros is the second full-length release by Canadian indie rock group Immaculate Machine. It is their first official release through Mint Records. Music videos were released for the songs "Broken Ship" and "So Cynical". as microscopic pits and valleys. A detector distinguishes laser light reflected from the contrasting surface features. Vo-Dinh now proposes an alternative storage approach, which he calls surface-enhanced Raman optical data storage (SERODS SERODS Surface-Enhanced Raman Optical Data Storage ). In the 1920s, physicist C.V. Raman discovered that the wavelengths of some of the light scattering scattering In physics, the change in direction of motion of a particle because of a collision with another particle. The collision can occur between two charged particles; it need not involve direct physical contact. from certain molecules differ from the wavelength of the light source, and that these differences carry information about the molecules' structures and abundances. Later, scientists observed that placing molecules close to certain surfaces such as silver enhances the Raman scattering effect, which otherwise is extremely subtle and difficult to detect. Extrapolating from his design of a soil analysis system using the enhanced effect, Vo-Dinh came up with the novel data storage approach. By coating a disk material such as silicon oxide with a film of silver and then with a layer of Raman-active molecules, Vo-Dinh can use a fine laser beam to induce specific microregions of the disk to produce distinctive Raman signals that serve as identifiable data bits. In a working SERODS system, ones and zeros would correspond to altered and unaltered microregions of the disk, respectively. Vo-Dinh's rough calculations predict that an optimized 12-inch SERODS disk could store 1 trillion letters -- well over 100,000 years' worth of SCIENCE NEWS. Preliminary tests show that no more than 1,000 molecules are needed to represent 1 data bit, says M. Guven Yalcintas, director of technology transfer at Oak Ridge. But turning this concept into a working device will take long-term commitments by many companies, he adds. |
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