Storage via light achieved: US researchers

A potential breakthrough has occurred, but its application remains elusive

US Researchers claim to be able to attach an image to a photon and retrieve it later.

Scientists at the University of Rochester used their college logo, which consists of a few hundred pixels, for the experiment. The photon or pulse of light was slowed down by 100 nanoseconds and compressed to 1% of its original length.

Researcher John Howell, assistant professor of physics at the university, is now working on delaying dozens of pulses for as long as several milliseconds — and as many as 10,000 pulses for up to a nanosecond — in a four-inch cell of caesium gas heated to 100 degrees Celsius.

Previous optical buffering trials have found most information carried by light is lost. The latest achievement is important because engineers are trying to speed up computer processing and network speeds using light. Their systems slow down when they have to convert light to electronic signals to store information, even for a short while.

Howell says, “It sort of sounds impossible, but instead of storing just ones and zeros, we’re storing an entire image. It’s analogous to the difference between snapping a picture with a single pixel and doing it with a camera — this is like a six-megapixel camera.”

“Now I want to see if we can delay something almost permanently, even at the single photon level. If we can do that we’re looking at storing incredible amounts of information in just a few photons.”

Previously, Techworld has reported researchers at Japanese telco NTT have slowed light down by having it enter a crystal with nano-scale holes inside it. IBM researchers have diverted light beams into microscopic rings to form a delay line and a Harvard University team has worked on slowing light down by passing it through very cold structures.

These four different research projects illustrate how important it is when building an optical computer not to have to convert from photons to electrons if data has to be stored in a buffer. The feasibility of long-term light storage, for periods longer than a few nanoseconds, has not been demonstrated at all, however. These projects are to do with caching information inside an optical computer, not storing data outside it.

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