Posted by: Sharon Fisher
data storage, research
We’re always into the geekly here at Yottabytes, like data under glass and so on. Naturally, we were fascinated to read about “freezing” light and its implications for data storage.
If you missed it, a detailed description comes from the BBC:
“The team fired a light beam called a signal pulse through a sealed glass cylinder containing a hot gas containing atoms of the element rubidium, illuminated by a strong ray of light known as a control beam. While the pulse was travelling through the rubidium gas, the researchers switched off the control beam, creating a holographic imprint of the signal pulse on the rubidium atoms,” the BBC reports. “Earlier experimental methods had then switched on a single control beam to recreate the signal pulse, which then continued on its way. However, in this latest study, researchers switched on two control beams which created an interference pattern that behaves like a stack of mirrors. As the regenerated signal pulse tries to continue on its way through the glass cylinder, the photons bounce back and forth, but the overall signal pulse remains stationary. The light beam was essentially frozen.”
The light was frozen for an entire minute. While this may not seem like long, it’s enough time for 20 round trips to the moon.
Another version was also printed in i09 (though in the process they said light traveled at 300 mps; hilarity ensued).
(You can also read the actual abstract.)
Research into the stopping-light area has been going on for some time, reports New Scientist. “Physicists managed to slow it down to just 17 metres per second in 1999 and then halt it completely two years later, though only for a fraction of a second. Earlier this year, researchers kept it still for 16 seconds using cold atoms.” In this particular experiment, the light-freezing was also enhanced using magnetism.
Where the storage comes in was part of the demonstration. “And they proved the accomplishment by storing — and then successfully retrieving — information in the form of a 100-micrometer-long picture with three horizontal stripes on it.” The one-minute storage time is about six orders of magnitude longer than previous experiments, notes the American Physical Society. Moreover, the fact that the storage time can be manipulated based on the use of magnetism means that storage could be “spatially multiplexed, i.e., can store different quantum bits as different pixels,” they write.
Of course, nobody’s talking yet about when this might actually be usable for storage. “The efficiency of the storage (<1% in the present scheme) will have to be significantly increased for applications,” the American Physical Society admits. However, the researchers are planning to try different substances to increase the duration of information storage. Tens of seconds of light storage are needed for a device called a quantum repeater, which would stop and then re-emit photons used in secure communications, to preserve their quantum state over long distances, New Scientist says.
There are also implications for security, the BBC adds. “Quantum cryptography might provide very secure forms of electronic encryption, because the process of eavesdropping on an electronic message would introduce errors in the message, garbling it.” How Heisenberg of it.