scipaTrying to stop light
November 25th 2007 18:57
So fact that scientists had to come up with a name for how fast it moves: the speed of light, otherwise known as 1,079,252,848.8 km/h, or one foot in one nanosecond.
Contrast this to everyday objects. You rarely hear people talk about the 'speed of apples' or even the 'speed of Cibbuano', though I'm working hard to make this a reality.
Fast as light is, people are always trying to slow it down. 'Relax, light,' they'll say, 'kick back and have a beer.'
It turns out this isn't so easy.... light is in an awful hurry to get where it's going. Consider it the irritated commuter of the physics world.
Why would you want to slow light down? Well, other than for the sheer challenge, it's extremely useful for making optical circuits - like electronics, but with light instead of electrons. That's where the fun really takes off.
In the recent issue of Wired Magazine, there's an article on Lene Vestergaard Hau, a physicist at Harvard who's managed to slow light down to 0.13 miles per hour. That's pretty damn slow.
Her secret is a tiny amount of a BEC - Bose-Einstein condensate, a low-temperature fluid that exhibits quantum behaviours on a macroscopic scale.
From the article:
"About a decade ago, Hau started playing with BECs — for a physicist, that means shooting lasers at them. She blew up a few. Eventually, she found that lasers of the right wavelengths could tune the optical properties of a BEC, giving Hau an almost supernatural command over any other light shined into it. Her first trick was slowing a pulse of light to a crawl — 15 mph as it traveled through the BEC. Since then, Hau has completely frozen a pulse and then released it."
These loose-wingnut physicists are lunatics trying to stop light. When they succeed, it'll open a new dawn of communications and information. You thought computers were fast now? You a'int seen nuthin' yet...
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