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Ultra-simple Desktop Device Slows Light To A Crawl At Room Temperature
Science Daily ^ | 4-1-2003 | Editorial Staff

Posted on 04/01/2003 7:25:59 PM PST by vannrox

Ultra-simple Desktop Device Slows Light To A Crawl At Room Temperature

Though Einstein put his foot down and demanded that nothing can move faster than light, a new device developed at the University of Rochester may let you outpace a beam by putting your foot down on the gas pedal. At 127 miles per hour, the light in the new device travels more than 5 million times slower than normal as it passes through a ruby just a few centimeters long.

Instead of the complex, room-filling mechanisms previously used to slow light, the new apparatus is small and, in the words of its creator, "ridiculously easy to implement." Such a simple design will likely pave the way for slow light, as it is called, to move from a physical curiosity to a useful telecommunications tool. The research is being published in this week's Physical Review Letters.

The new technique uses a laser to "punch a hole" in the absorption spectrum of a common ruby at room temperature, and a second laser shines through that hole at the greatly reduced speed. A recent successful attempt to slow light to these speeds used a Bose-Einstein condensate (BEC), a state of matter existing 459 degrees below zero Fahrenheit where all atoms act in unison like a single, giant atom. The laser shining through the BEC was slowed to 38 miles per hour, but the system had enormous drawbacks, not the least of which was that the equipment needed to create the BEC wouldn't fit in the average living room, and the created BEC itself was little bigger than the head of a pin.

"If that was the world's hardest way to slow down light, then what we've found is the world's easiest way to do it," says Robert Boyd, the M. Parker Givens Professor of Optics at the University. "We can slow light just as much in a space the size of a desktop computer."

Slowing light, at least a little, isn't as difficult as it may seem. Light passing through a window is 1.5 times slower while moving through the glass, and is slowed slightly less so when passing through water. But to achieve the 5.3-million fold slowdown, Boyd and his team, students Matthew Bigelow and Nick Lepeshkin, used a quantum quirk called "coherent population oscillations" to create a special gap in the frequencies of light that a ruby absorbs. Rubies are red because they absorb most of the blue and green light that strikes them. Shining an intense green laser at the ruby partially saturates the chromium ions that give ruby its red color. They then shine a second beam, called the probe laser, into the ruby. The probe beam has a frequency slightly different than the first laser, and these offset frequencies interact with each other, causing variations the same way two ripples encountering each other on a pond might create waves higher and lower than either one had alone.

The chromium ions respond to this new frequency of rhythmic highs and lows by oscillating in sympathy. One consequence of this oscillation is that it allows the probe laser to pass through the ruby, even though the laser is green, but it only allows it to pass 5.3 million times more slowly than light would otherwise travel.

Boyd anticipates that the slow light device will find a role in the telecommunications industry. When two signals from fiber optic lines merge, the two signals may reach the merging router at the exact same moment and need to be separated slightly in time so they can be laid down one after another. Like two cars merging on a highway where one may need to slow down to let another car into the lane, a light-slowing device could help ease congestion on fiber optic lines and simplify the process of merging signals on busy networks.

One drawback to the new technique is currently being scrutinized by Boyd and his coworkers--the duration of the pulses of light that it delays are very long. The BEC experiments were able to delay a short pulse, which meant that a plain pulse of light and a slowed pulse would differ by several times the pulses' lengths. The Boyd technique slows light by roughly the same amount as the BEC method, but since the pulses are much larger, the delay is only a fraction of the pulses' size. It would be the difference between slowing an economy car a few feet to let another economy car merge, and a double-tractor trailer slowing only a few feet and expecting another double trailer to merge into the gap. Boyd suspects that different materials may yield slowed light that can transmit shorter pulses that would be more useful for telecommunications work.

Editor's Note: The original news release can be found here.

Note: This story has been adapted from a news release issued for journalists and other members of the public. If you wish to quote any part of this story, please credit University Of Rochester as the original source. You may also wish to include the following link in any citation:

http://www.sciencedaily.com/releases/2003/04/030401072655.htm


TOPICS: Business/Economy; Culture/Society; Extended News; News/Current Events
KEYWORDS: engineering; ftl; knowledge; light; new; physics; realscience; science; techindex; technology
COOL.
1 posted on 04/01/2003 7:25:59 PM PST by vannrox
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To: vannrox
Note to Self:

Don't release anything groundbreaking on April Fools Day. Everything is suspect.

2 posted on 04/01/2003 7:28:43 PM PST by freedomlover
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To: vannrox
......<--I made a really cool reply to this post but it isn't here yet.
3 posted on 04/01/2003 7:29:40 PM PST by isthisnickcool
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To: vannrox
the light in the new device travels more than 5 million times slower than normal . . . 1.5 times slower . . .5.3-million fold . . . slowdown

Arrgggh! Pet peeve alert, mathematically, a mere 1-fold slowdown means 0 miles per hour. Saying something is 5 million times slower or 1.5 times slower or 5.3 million times slower is just so much innumeracy.

4 posted on 04/01/2003 7:31:41 PM PST by stayout
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To: freedomlover
The Original press release is dated 3/31. Passes the smell test....
5 posted on 04/01/2003 7:32:20 PM PST by Leroy S. Mort
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To: vannrox
Any implications re the structure of matter/the universe?
6 posted on 04/01/2003 7:32:25 PM PST by Quix (QUALITY RESRCH STDY BTWN BK WAR N PEACE VS BIBLE RE BIBLE CODES AT MAR BIBLECODESDIGEST.COM)
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To: vannrox
the Utah effect strikes again....


7 posted on 04/01/2003 7:34:04 PM PST by longtermmemmory
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To: vannrox
Will "slow glass" be next?
8 posted on 04/01/2003 7:34:06 PM PST by narses (Christe Eleison)
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To: vannrox
What the heck is with the ruby?!
9 posted on 04/01/2003 7:34:24 PM PST by RandallFlagg ("There are worse things than crucifixion...There are teeth.")
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To: isthisnickcool
And, moreover, you yourself will comprehend it only tomorrow, when it finally traverses the path from the hand to the brain...

Until yesterday, TQ.

10 posted on 04/01/2003 7:34:44 PM PST by TopQuark
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To: vannrox
I misread headline at first, thought it was describing a place I used to work at where they gave me a 286. It took 4 minutes to boot up:

Ultra-simple Desktop Device Slows To A Crawl At Room Temperature


11 posted on 04/01/2003 7:36:58 PM PST by bwteim (bwteim=Begin With The End In Mind)
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To: vannrox
So can this thing slow down my bedroom activity and ~ummm, ~you know, ~how do I say... my pleasure release?
12 posted on 04/01/2003 7:41:22 PM PST by Drango (Two wrongs don't make a right...but three lefts do!)
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To: freedomlover
Don't release anything groundbreaking on April Fools Day. Everything is suspect.

Heh, you've got that right. Some sites (Slashdot) I just steer clear of completely on April 1.

13 posted on 04/01/2003 7:42:11 PM PST by algol
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To: vannrox
I thought this thread was going to be about public school education.
14 posted on 04/01/2003 7:48:30 PM PST by PatrioticAmerican (Arm Up! They Have!)
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To: isthisnickcool
LOL
15 posted on 04/01/2003 8:18:42 PM PST by CanadianYankee
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To: vannrox
A small question. Since energy is mv^2, what happens to the the extra energy when the light slows down? Is the wavelength shifted? I assume from reading that it emerges at the same wavelength.

What if you could really slow it down (a millimeter per minute). You then pump a powerful laser in for a few minutes and turn it off. You then turn off the original laser that works on the chromium atoms. What happens to the enery? The ruby melts? Or do you get one heck of a beam out the other end (i.e. suitable for punching through lots of nifty things)? Or do you get a slow release?

Just asking.

16 posted on 04/01/2003 8:47:09 PM PST by pierrem15
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To: vannrox
I was just mentioning something similar to this to my local bar-friend the other day.

He wanted to know if a short packet of light (say 2-3 inches in length) were propagated in this manner, if one could see the packet traverse the room. I said I think that it only slows while it is going through the slowing-device.

He then wanted to know if the pulses of light would “bunch up” as they entered the slowing-device, causing a standing wave or some bunching phenomenon at the "entrance". I said that I didn’t think so, because light doesn’t bunch up at a (for example) window (does it?).

We then concentrated on a bug crawling across the bar.
17 posted on 04/01/2003 8:48:16 PM PST by Diddley (Apr 1, 2003)
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To: *tech_index; *RealScience
http://www.freerepublic.com/perl/bump-list
18 posted on 04/01/2003 9:12:27 PM PST by Libertarianize the GOP (Ideas have consequences)
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To: Diddley
LOL!
19 posted on 04/02/2003 2:30:05 AM PST by kitkat (HANDYMAN'S SPECIAL: First Avenue, NYC, former site of the U.N.)
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To: narses
Will "slow glass" be next?

That's the first thing I thought, too! The story by Bob Shaw.

20 posted on 04/02/2003 2:37:18 AM PST by Trickyguy
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To: kitkat
:-)
21 posted on 04/02/2003 6:43:27 AM PST by Diddley (Liberals: If you have a good story, why lie?)
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To: vannrox
This implies that even a moron can now think at the speed of light ....
22 posted on 04/02/2003 6:52:35 AM PST by sphinx
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To: freedomlover
It is not an April Fool's joke. I spoke to the person who wrote the press release. There is an abstract for the paper here.


23 posted on 04/02/2003 8:12:11 AM PST by Ziva
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To: Ziva
It is not an April Fool's joke. I spoke to the person who wrote the press release. There is an abstract for the paper here.

I'm not saying it is. I'm just saying why release anything along these lines within shouting range of April Fools Day.

But then again, perhaps thou does protest too much. LOL

24 posted on 04/02/2003 8:19:12 AM PST by freedomlover
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To: narses
Will "slow glass" be next?

Ahhh, another avid sci-fi reader, I see! I was thinking of the same story when I read this.

25 posted on 04/02/2003 9:40:26 AM PST by FierceDraka (Semper Fi, Do or Die, Gung Ho Gung Ho!)
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To: vannrox
Ultra-simple Desktop Device Slows Light To A Crawl At Room Temperature

Hell, I thought it was an article about my dial-up modem.

26 posted on 04/02/2003 9:48:07 AM PST by KC Burke
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