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Comments: 72 +- Science: Tapering Waveguide Captures a Rainbow on Saturday November 28, @02:51PM
Posted
by
kdawson
on Saturday November 28, @02:51PM
from the you-fight-with-light-surely-that-is-forbidden dept.
from the you-fight-with-light-surely-that-is-forbidden dept.
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science
SubComdTaco passes along news of researchers in the US who have trapped a rainbow in a tapering waveguide. The research is described (PDF) on the arXiv. "In 2007, Ortwin Hess of the University of Surrey in Guildford, UK, and colleagues proposed a technique to trap light inside a tapering waveguide [made of metamaterials]... The idea is that as the waveguide tapers, the components of the light are made to stop in turn at ever narrower points. That's because any given component of the light cannot pass through an opening that's smaller than its wavelength. This leads to a 'trapped rainbow.' ... Now Vera Smolyaninova of Towson University in Baltimore, Maryland, and colleagues have used a convex lens to create the tapered waveguide and trap a rainbow of light. They coated one side of a 4.5-mm-diameter lens with a gold film..., and laid the lens — gold-side down — on a flat glass slide which was also coated with film of gold. Viewed side-on, the space between the curved lens and the flat slide was a layer of air that narrowed to zero thickness where the lens touched the slide — essentially a tapered waveguide. When they shone a multi-wavelength laser beam at the... gilded waveguide, a trapped rainbow formed inside. This could be seen as a series of colored rings when the lens was viewed from above with a microscope: the visible light leaked through the thin gold film."
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Leprechaun (Score:5, Funny)
So the bloody leprechaun lied to us !
You need to have two very thin pots of gold first, so you can find the end of the rainbow.
Leprechaunic (Score:5, Funny)
>>You need to have two very thin pots of gold first, so you can find the end of the rainbow.
I wonder if you kidnap the scientists they'll grant you three wishes?
Tag: Leprechaun
Parent
Re:Leprechaunic (Score:5, Funny)
I wonder if you kidnap the scientists they'll grant you three wishes?
Yes, unless one of the wishes is to know how your cat is doing.
Parent
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No, you can wish for that, it's just that your wish may or may not actually get used up.
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We all assuming its pots of real gold at the end of the rainbow. Leprechauns lied once, they'll lie twice. I saw its pots of fools gold.
I think the US Gold Reserve isn't in Fort Knox. Its at the other side of the rainbow too. ;)
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oh your one of those people that think IQ is everything and strength or stamina are not neccessary
Playing devil's advocate here (the poster you're responding to is a lame troll posting the same crap over and over again, and you're also pretty wrong to say that genetically Africans tend to be great athletes and Westerners are better scientists) - stamina and strength can both be acquired through training, intelligence only in a very limited fashion. So yeah, intelligence is more precious than physical strength.
Not exactly a pot... (Score:2)
But the ends still technically had gold beneath them.
skittles (Score:4, Funny)
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Tastes like shiny.
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You obviously haven't eaten enough acid. Eat these two sugar cubes, and tell me what the rainbow tastes like in about 30 minutes.
-Dr JWSmythe
(if only all prescriptions were this easy, or entertaining.)
What they're really researching (Score:5, Funny)
Amazing work, but brings to mind a quote (Score:5, Interesting)
--Bill Watterson, via Hobbes in Calvin and Hobbes.
Also neat because? (Score:2)
Okay, aside from the obvious "nifty" factor, can someone explain in dummy-terms what other cool stuff this might lead to? I realize that research isn't necessarily about making immediately useful things, but surely someone knows of some fantastic avenues this might lead towards?
Not trying to downplay any significance here, just looking for some insight from someone more familiar with what's going on. :)
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Nevermind, I just managed to RTFA. :D
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(Optical computing was the answer.)
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Black holes have been trapping light since the Big Bang (or "shortly afterwards" anyway, in cosmic terms).
I think God has prior art on that one. Once man can also trap gravity, strong and weak electromagnetic forces and time, I'll concede to your assertion.
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I think God has prior art on that one. Once man can also trap gravity, strong and weak electromagnetic forces and time, I'll concede to your assertion.
If that was in list of increasing difficulty, already done as I know several school teachers who could turn an hour into eternity.
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Two very important quotes to remember....
"God is dead. God remains dead. And we have killed him." -Nietzsche
"Nietzsche is dead." -God
One is pretty easy to verify. There's a gravestone in Germany [findagrave.com] with his body under it. Well, I assume it's still there. in 1998, they were talking about digging up the area to strip mine for coal. Hmmm.
As for God, I haven't seen his gravestone quite yet. Then again, no one has ever seen his body, s
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Damned proof reading. That was the 1980's and 2008, not 1998.
I like soap bubbles better... (Score:5, Interesting)
Like an interference pattern? (Score:5, Interesting)
Sounds like an old high school science experiment. Take two microscope slides (flat pieces of glass) lay one on top of another with a thin shim separating them at one end, illuminate this with a monochromatic light and see the fringes. With white light, the peaks for each wavelength would occur at different locations, resulting in a 'rainbow'. Same thing works with soap films, using internal reflection, as the film flows downwards due to gravity and becomes thicker at the bottom (wedge-shaped).
This is also a neat trick for measuring the thickness (or diameter) of a small object. Using it as the shim, count the fringes per centimeter, do some math and you know how thick it is.
Newton's Rings (Score:5, Informative)
Sounds like an old high school science experiment. Take two microscope slides (flat pieces of glass) lay one on top of another with a thin shim separating them at one end, illuminate this with a monochromatic light and see the fringes. With white light, the peaks for each wavelength would occur at different locations, resulting in a 'rainbow'.
What you're referring to is known as "Newton's Rings":
http://en.wikipedia.org/wiki/Newton's_rings [wikipedia.org]
Parent
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Exactly what I was thinking too.
Nothing new here, move along... (Score:2, Informative)
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I did read the article (which is one page, and contains nothing complicated). It's *exactly* a Newton's rings experiment, and has practically nothing to do with metamaterials, nor with an "adiabatically-tapered waveguide", as the article claims. Looks to me as though New Scientist did some _very_ sloppy reporting, and /. got snookered into picking it up as real research.
I'm interested to see what journal that gets in (Score:4, Insightful)
It was a very simple experiment to perform. It doesn't make any measurement of the group velocity or demonstration of trapped light (which would typically involve releasing it controllably and detecting it). The original proposal involved meta-materials to achieve a region with a negative index of refraction to use as the waveguide. They could then (hopefully) manipulate the meta-material to controllably store and retrieve light.
It seems this experiment used a simple meta-material the consisted of the glass surfaces, the 30-nm gold coating and the air gap in a Newton's rings setup. They may even have had the gold coated lens lying around and did the experiment over lunch (which just involved taking a picture). I don't think it's all that interesting until they get storage and retrieval.
TU is not in Baltimore, MD (Score:2)
RE: Newtons Rings type experiment. (Score:2, Insightful)
It started out fine (Score:2)
And then, the rainbows turned on us, the seven frequencies combining their harmonics into a single meta-Frequency
A frequency . . . of DEATH!!!!!
RUN - SAVE YOURSELVES!!!!
Re:What happens when the laser is turned off? (Score:5, Informative)
Parent
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Every time the light bounces off of whatever you have contained it in, it will lose a bit of energy. Since it's traveling at the speed of light, you'll have enormous numbers of bounces per second and they'll quickly sap all of the energy away from the beam
Interesting theory, but where does this energy go ? Is it converted to sound, heat, mass, or some other form ? It doesn't simply disappear, unless Albert Einstein was drunk when he postulated the theory of relativity !
And if we could completely "sap all th
Re:What happens when the laser is turned off? (Score:5, Interesting)
Interesting theory, but where does this energy go ? Is it converted to sound, heat, mass, or some other form ?
Heat.
And if we could completely "sap all the energy" away from the beam, wouldn't this imply we could create 100% effecient solar cells ?
As long as you're happy with heat as output, 100% efficient solar cells are quite trivial.
Parent
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As long as you're happy with heat as output
So how about we create a tiny stirling engine and put it at the end of two gold plated cone shapes, one inside the other with a tiny tapering distance between them, and for good measure, enclosed in a vacuum ?
Wouldn't this allow the incoming light source to be trapped on 3 dimensions and focused down to a concentrated point ? Sure we couldn't see the rainbow any more, but the "light leakage" concerns would seem to be covered, and by the comments above, the only pla
Re:What happens when the laser is turned off? (Score:4, Informative)
As for the solar cells thing... no. That's a completely different situation. The trapped rainbow is a nearly closed system, with no continuous energy input, and the problem is that we can't make it completely closed (and if we could, it's internal entropy would then increase over time so it still couldn't be perfectly stable). Technically, I suppose all the energy can't be sapped since it's exponential decay, but the system energy asymptotically approaches 0 (and once a small enough amount remains, the fact the energy is discrete becomes important). It's about inefficient energy conversion. Far form implying that we could create 100% efficient solar cells, this is why we can't create 100% efficient solar cells.
Parent
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it is all lost to heat.
wouldn't this imply we could create 100% effecient solar cells ?
No, just very very black objects that get hot in the sun. If you could make them NOT get hot, get heavier, or vibrate then YES, you would be rich.
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That was my thought on it. They aren't "capturing" it. They're looking at refracted light. It's a very fancy prism. They spent a lot of money on water drops. Otherwise, they should be able to quantify the photon dust on the bottom of their apparatus. :) ... and I was just making a joke about the photon dust, but I googled it, and it's theorized to exist. Well, kinda. :)
I guess there's gotta be something at the bottom of a black hole from all that light that can't escape,
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Just don't stand too close to the cell.
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Just because we create something does not mean that we can claim ownership of it, I wonder if that's why no one has ever seen god?
I think the RIAA might disagree with you on the first point.
And no one has seen God because he's been involved in a long legal battle with Michael Jackson over buying back the rights to "The Universe" back catalogue.
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Your musings sound not so much like Asimov's fiction, but futurist Ray Kurzweil's predictions in books like The Singularity is Near [amazon.com] . One of Kurzweil's observations is that as soon as we can crea
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Ummm, if we could produce a computer (and program it) to be equivalent to the human brain, wouldn't *IT* be making the next one? Come on, it wouldn't need sleep. It wouldn't take weekends off. It wouldn't take smoke breaks. It wouldn't go on shooting rampages when it was overstressed and underpaid (I hope). It wouldn't only work 8 to 14 hour days. It wouldn't have to stop working to take a leak. It wouldn't be having dirty dreams about that hot 18 year old intern named Natasha (MMmm, N
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One of Kurzweil's observations is that as soon as we can create a machine equivalent to a human brain, we can create a machine more powerful than a human brain.
Which would also mean that we wouldn't be that far away from creating a machine capable of enhancing the human brain.