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Edited by Euler: 7/26/2013 8:01:45 AM
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Euler

Light frozen for an entire minute

[quote]The fastest thing in the universe has come to a complete stop for a record-breaking minute. At full pelt, light would travel about 18 million kilometres in that time – that's more than 20 round trips to the moon. "One minute is extremely, extremely long," says Thomas Krauss at the University of St Andrews, UK. "This is indeed a major milestone." The feat could allow secure quantum communications to work over long distances. While light normally travels at just under 300 million metres per second in a vacuum, 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. To break the minute barrier, George Heinze and colleagues at the University of Darmstadt, Germany, fired a control laser at an opaque crystal, sending its atoms into a quantum superposition of two states. This made it transparent to a narrow range of frequencies. Heinze's team then halted a second beam that entered the crystal by switching off the first laser and hence the transparency. The storage time depends on the crystal's superposition. A magnetic field extends it but complicates the control laser configuration. Heinze's team used an algorithm to "breed" combinations of magnet and laser, leading them to one that trapped light for a minute. [/quote] [url=http://www.newscientist.com/article/dn23925-light-completely-stopped-for-a-recordbreaking-minute.html]Link to Article[/url] So this technology obviously has fundamental quantum encryption and data transmission applications, but no one really gives a toss because lightsabers!11eleven!

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  • Guys, this has literally nothing to do with lightsabers. It's a shame that a scientific news source would make such an obviously-lowbrow title just to attract readers. The light wasn't frozen at all. Basically, they put light into a prism which was made transparent by another light source. Just image a clear glass box. Then, with the light source shining into the prism, they shut off the other light source that was keeping it transparent. In the analogy, imagine someone putting a reflective sheet over the box to stop the light from escaping. The light that was in the prism was unable to escape because it was opaque, meaning light can't penetrate its sides. But the light also wasn't immediately absorbed into the material due to the properties of the crystal. This light was then trapped for a minute, after which all of the light had been absorbed into the material. This is analogous to cooking a steak and then putting foil over it to keep the heat in to let it cook a bit longer. They didn't "freeze" light at all, they just utilized a particularly opaque material.

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