Optical computers seem to be creeping closer and closer to reality with various groups making breakthroughs on necessary components. One of the challenges facing scientists for creating an all-optical computer is memory. While various components are capable of holding an electrical charge for the sake of storing information, light is not so easy to work with. Researchers in a Duke University-led team may have a means to alleviate this problem.

The group reports that a phenomenon called "Stimulated Brillouin Scattering" (PDF) can be used to imprint data into an optical fiber. Rather than a function of light itself, the data is stored as a vibration caused by opposing laser beams passing through the same fiber. These vibrations are known as phonons.

The light used to create the phonons must be of different wavelength in order to interact with each other and create the data imprint. Once the data exists, a third laser can be shined through the optical material to "read" its vibrations and convert the data back to light.

Though these phonons only last about 12 billionths of a second, optical transfer rates would be much faster, allowing a refined technology to function as a short term storage medium. The group's report suggests that other optical materials may hold the phonons longer and be more suitable for long-term storage.

The process works at room temperature and at frequencies commonly used in optical telecommunications. One shortcoming is that the pulses of laser used to generate and read the data require about 100 watts of power, much too high for use in a computer.

"I'm hoping that other scientists around the world will come up with new ideas based on our work," said Daniel Gauthier, a Duke physics professor and the report's corresponding author. "The Duke team will also be pushing the state of the art in this field with our own ideas."