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Supercomputing Science

Scientists Trap a Rainbow 147

Posted by ScuttleMonkey from the i-can-c-the-light dept.
An anonymous reader writes to tell us that Physicists from both the University of Surrey and Salford University have devised a method to trap a multi-colored rainbow of light inside a prism. "Previous attempts to slow and capture light have involved extremely low or cryogenic temperatures, have been extremely costly, and have only worked with one specific frequency of light at a time. The technique proposed by Professor Hess and Mr Kosmas Tsakmakidis involves the use of negative refractive index metamaterials along with the exploitation of the Goos Hänchen effect, which shows that when light hits an object or an interface between two media it does not immediately bounce back but seems to travel very slightly along that object, or in the case of metamaterials, travels very slightly backwards along the object."
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Scientists Trap a Rainbow

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  • In Rainbows (Score:4, Funny)

    by Anonymous Coward on Monday November 19, 2007 @12:44PM (#21409627)

    Scientists Trap a Rainbow
    When PETOR (People for the Ethical Treatment of Rainbows) finds out about this, they are going to be pissed.

    It shouldn't hurt to be a photon.

  • Did they get the pot of gold as well? (Score:5, Funny)

    by Joe The Dragon ( 967727 ) on Monday November 19, 2007 @12:45PM (#21409637)
    Did they get the pot of gold as well?

  • it's not all fun and games... (Score:4, Funny)

    by MrAndrews ( 456547 ) * <mcm@1889.BOYSENca minus berry> on Monday November 19, 2007 @12:46PM (#21409651) Homepage
    There's a protest against capturing rainbows [pttbt.ca] going on today in NY... looks like it's a murky ethical question...
    • I am waiting for the Rainbow coalition to weigh in on this.

      Rainbows are people too.
    • Are they stacking these prisms into pyramids, like Abu Ghraib (and Dachau)?

      Ponies and rainbows! Who will save the ponies and rainbows?
    • But don't they get it? This could lead to one of the greatest discoveries in all of science.
      What if we could find the fabled rainbow collection, predicted as early as 1979?
      Well, fine. If the lovers and dreamers won't help, I'll just have to do it all by myself.
  • that if Apple brings back the old logo they will rule the Intarweb tubes?
  • ...Over or UNDER the bridge?

    (Captcha: cadaver)

  • Scientists Trap a Rainbow (Score:4, Interesting)

    by niceone ( 992278 ) * on Monday November 19, 2007 @12:51PM (#21409733) Journal
    Or they don't. They propose a method that might. The meta-materials needed to do this with visible light don't exist yet.

    • Re:Scientists Trap a Rainbow (Score:4, Interesting)

      by Dunbal ( 464142 ) on Monday November 19, 2007 @01:03PM (#21409919)
      Now they have to think of a way to get the light "out" again. Because after all, what's the point of storing charge in a capacitor's electric field, if you can't get your electrons back when you need them?

      The other interesting thing is - if you don't let the light out, how much light can you put in there? Does it "fill up"? And if it does, what happens when it does? Does the universe end or something?

      • Re:Scientists Trap a Rainbow (Score:5, Interesting)

        by kebes ( 861706 ) on Monday November 19, 2007 @01:26PM (#21410221) Journal

        Now they have to think of a way to get the light "out" again.
        A specific device hasn't been built, but I imagine it would be optoelectronic: that is, they would design the material so that application of an electric field would turn off (or on) the metamaterial effect. If you could switch the capturing capability of the device with an electric current, then obviously you could integrate it into some sort of routing circuitry. In principle one could also design the material to have some unique non-linear optical properties, so that light alone was used to regulate its behavior (e.g. after enough light gets trapped it saturates and releases it), but this kind of "all optical routing/computing" is sorta the "holy grail" of telecom.

        The other interesting thing is - if you don't let the light out, how much light can you put in there?
        In theory it would build up forever. In reality, any device will be imperfect and probably won't capture light "forever" (but a year or even a minute would be "effectively infinite" for most real-world applications). I imagine that if enough light got "trapped" inside, the resultant EM field in the material would get intense enough to alter the material properties. Eventually the material would break-down, stop being a meta-material, and release the captured light. As I alluded to before, if this were carefully designed it could have some interesting effects (e.g. a "light capacitor" that builds up a big pulse and then releases it all at once).

        In any case, I wouldn't worry about the universe ending!

        • Re: (Score:2)

          by Dunbal ( 464142 )
          but I imagine it would be optoelectronic

          Yeah I thought it would have to be pretty much along those lines - but, but, wouldn't that slow everything down? I mean the whole POINT of using light is that it's faster, etc. But then you need an electronic system to do the switching for you, so it will only be as fast as your electronics and the speed at which you can switch the thing (the material itself).

          It would be neat if instead, light and interference patterns or so
        • "As I alluded to before, if this were carefully designed it could have some interesting effects (e.g. a "light capacitor" that builds up a big pulse and then releases it all at once)."

          Indeed actually, now that I think of it, this sounds similar *pulsing* to how the brain functions.

        • Eventually the material would break-down, stop being a meta-material, and release the captured light. As I alluded to before, if this were carefully designed it could have some interesting effects (e.g. a "light capacitor" that builds up a big pulse and then releases it all at once).

          That sounds like a bomb to me. A laser bomb...

      • Re: (Score:2)

        by Dan Ost ( 415913 )
        Because after all, what's the point of storing charge in a capacitor's electric field, if you can't get your electrons back when you need them?

        It's a common misconception, but capacitors don't store electrons. They store energy. The number of electrons remains constant.
      • No, Morgoth just comes along and steals 'em. But then we have to deal with a bunch of pissed of Noldor rampaging around, what with their secret kingdoms and bloody Oath. :(

    • Re:Scientists Trap a Rainbow (Score:5, Informative)

      by kebes ( 861706 ) on Monday November 19, 2007 @01:15PM (#21410073) Journal
      First off, for those interested (and with subscriptions) let me provide a reference to the actual paper (from last week's Nature):
      Kosmas L. Tsakmakidis, Allan D. Boardman & Ortwin Hess 'Trapped rainbow' storage of light in metamaterials [nature.com] Nature 450, 397-401 (15 November 2007) | doi: 10.1038/nature06285 [doi.org]. (See also summary comment box [nature.com], doi 10.1038/450330a [doi.org].)

      They propose a method that might. The meta-materials needed to do this with visible light don't exist yet.
      Your caution is quite correct. The paper is theoretical. An actual device has not yet been built. However this result is still significant because what they are showing is that the various results on "slow light" and "trapped light" can be realized in optical metamaterials. This is significant because metamaterials are in principle more amenable to technological deployment than the more exotic techniques of slowing light (ultra-cold condensates, etc.).

      It's also worth noting that metamaterials at various wavelengths (e.g. microwave band and IR) have already been made. We are getting very close to optical metamaterials. For instance, see this review of the field:
      Vladimir M. Shalaev Optical negative-index metamaterials [nature.com] Nature Photonics 1, 41 - 48 (2006) doi: 10.1038/nphoton.2006.49 [doi.org].

      We already have prototype metamaterials at wavelengths of 780 nm, which is on the edge of the visible spectrum. Significantly, we already have metamaterials that operate in the IR band, which is what is used for modern fiber-optics, telecommunications, etc. The materials to date are not optimized, so it will of course be awhile before all these great applications of metamaterials are implemented in real telecom devices. But, still, we are getting quite close to these applications. In particular, I expect we'll see a commercial 'rainbow trapping' device for communications before we see a commercial 'invisibility cloak'!

      • Re: (Score:1)

        by Smauler ( 915644 )

        I absolutely _hate_ the term metamaterial. I know about its use and the reasons for its creation, but metamaterial is a stupid word, which does not mean what it says. Structure, for a long long time has been more important than composition. Carbon is a fun example. It is absolutely oxymoronic in my opinion to claim something above a material while using that material as an example...

  • The Phantom Zone isn't a nice place.

  • !pleh (Score:1, Funny)

    by Anonymous Coward
    !rorrim ym ni kcuts m'I ,em pleh esaelp
  • Roads all across Ireland are blocked by thousands of Leprechauns protesting against capturing and inhumane treating of rainbows.

  • Light Labyrinth? (Score:4, Funny)

    by Doc Ruby ( 173196 ) on Monday November 19, 2007 @01:02PM (#21409909) Homepage Journal
    Has anyone worked on making devices or materials that channel light along a very long internal optical path folded up inside a small volume? Maybe some kind of photonic crystal that takes a laser input at a precisely calibrated angle, that reflects off nanoscopic features all throughout, or an optical medium with precisely aligned internal reflecting surfaces to cycle the light around, moving across the reflection surfaces gradually with each cycle through them, until the light reflects at an angle that escapes? Since photons interact only at the locus where they actually interfere and travels straight without confinement, the light doesn't need extra structure to segregate it. A long enough reflection path could emit light at its end only after a long time internally reflecting, which could offer enough time to move a properly positioned reflector "cap" over the entrance/exit. That device wouldn't slow light, but it would delay it, and then store it, entirely optically. Perhaps offering a purely photonic battery.

    Am I making this up myself, or is it serendipity?

    • Re: (Score:2)

      by Dunbal ( 464142 )
      I'm having visions of a circular piece of fiber optic sort of like a "Q" where light is put in at the little straight bit and then travels endlessly in circles...

      Dude, pass the bong.
      • I think a very long fiber, maybe thousands of Km long, with half mirrored ends (like a laser crystal rod has), could do this, but I'm thinking of using actual reflection, rather than total internal reflection at the critical angle.

        Make a helluva lighter.

    • Re: (Score:2)

      by SSpade ( 549608 )
      I think you just reinvented slow glass [scifi.com]
      • Actually, I think I just slid the engineering fiction into the vacuum between Shaw's science fiction and romantic fiction. Not bad, at first glance.

    • Re:Light Labyrinth? (Score:4, Informative)

      by kebes ( 861706 ) on Monday November 19, 2007 @01:36PM (#21410387) Journal

      Has anyone worked on making devices or materials that channel light along a very long internal optical path folded up inside a small volume?
      It's a neat idea, and in real-world optics such tricks are sometimes used. For instance you can set up two mirrors, and have the beam bounce back-and-forth between them, in order to introduce a known delay into a particular beam path (you can increase the traveled path by a rather large amount). Another simple trick is just to launch a pulse into a big roll of fiber-optic.

      The main problem with such techniques is losses. Even if your mirror is 99.9% reflective (and mirrors that good are expensive, by the way), you quickly lose all your signal intensity if you are reflecting thousands or millions of times. Your idea of using a photonic crystal is neat, but you would be hard-pressed to make a very long path length without making the crystal large, too. And if you cap the end with a mirror (to trap the light for longer), you run into losses from that.

      That's one of the reasons the research mentioned in TFA is significant: in principle it allows a pulse to be trapped for an arbitrary amount of time with no losses (and for a broad range of wavelengths).
      • The inefficiency in reflections is light converting to heat when interacting with the medium. What exactly is that mechanism called? And is refraction, rather than reflection, ever 100% efficient?

        • Re:Light Labyrinth? (Score:4, Informative)

          by kebes ( 861706 ) on Monday November 19, 2007 @02:27PM (#21411187) Journal

          The inefficiency in reflections is light converting to heat when interacting with the medium. What exactly is that mechanism called?
          There are a variety of effects that lead to losses. There is simple absorption, where light is converted to heat. Any real material will have a non-zero absorbance. Also, to achieve high reflectivity you want a high refractive index contrast. Vacuum has a nice low refractive index, but of course there is no material with an infinite refractive index, so you will always get some transmission into the material. Unless the surface is truly perfect you will also get some amount of scattering that sends off light in other directions.

          There are similar problems with refraction: the refractive index contrast is not infinite, so some amount of light is always transmitted. At glancing angles (below the critical angle), you theoretically get perfect 100% internal reflection. This is how fiber-optics work: by having a glancing-angle internal reflection, the losses at the boundary are quite low. However the beam is then propagating inside a material, and there is absorption from the material itself. (Even if the absorption was somehow zero, the refraction at the boundary would never be perfect: imperfections and evanescent waves would cause some amount of light to escape.)

          So, while theoretically one could build a light-trap using reflection or refraction, using any known material would involve some imperfections or losses preventing long-term trapping.
          • Something I find interesting about these mechanics is that it seems that even light with a wavelength that does not match any of the quantum levels of the atoms of a translucent material can somehow be absorbed by that material. Is that because the atoms have an infinite amount of quantum levels, stretching outwards from the nucleus, with at least one level available somewhere in its "stack" for any incoming wavelength light, or because every material has impurities which inevitably have some (relatively lo

            • Re: (Score:2)

              by kebes ( 861706 )

              It seems to me that the quantum nature of these effects should offer lots of "no strings attached" ways to interact with 100% "elasticity" that human scale matter's statistical average behavior makes impossible.

              Actually it seems more like the opposite (unfortunately): quantum effects tend to ruin any hopes of a 100% anything. In a classical system, you can construct something that is trapped within a "potential energy well", but in quantum mechanics, tunneling [wikipedia.org] means that there will always be a non-zero probability of the "thing" escaping from the trap by tunneling through the barrier (this is, for example, how radioactivity works: by nucleons tunneling out of the strong binding in the nucleus). You can make a tra

              • OK, since I've found the first Slashdot thread in months that's more light than heat (pun intended :), maybe you can explain whether light moving through the curved space past a mass doesn't just "pull" the mass and light closer, but does it also change the energy in the light, which I would expect to be measurable as a lowered frequency?

                And if so, is there a way to make nanoscopic light frequency shifters by moving masses closer/farther near light's path, perhaps shining in a vacuum channel? What if the li

                • Re: (Score:3, Informative)

                  by kebes ( 861706 )

                  explain whether light moving through the curved space past a mass doesn't just "pull" the mass and light closer, but does it also change the energy in the light, which I would expect to be measurable as a lowered frequency?

                  Light is affected by gravitational fields (as explained by Einstein/relativity), so a beam of light is deflected by the presence of a massive object. Note, however, that light (photons really) have no mass hence they do not attract (or "pull") the mass in any way. A beam of light is deflected by a star or planet because spacetime itself is "curved", as you say. The photons don't really lose/gain any energy in the process, but their wavelength/frequency is indeed shifted by the gravitational field (energy i

              • Re: (Score:2)

                by kmac06 ( 608921 )

                Actually it seems more like the opposite (unfortunately): quantum effects tend to ruin any hopes of a 100% anything. In a classical system, you can construct something that is trapped within a "potential energy well", but in quantum mechanics, tunneling means that there will always be a non-zero probability of the "thing" escaping from the trap by tunneling through the barrier (this is, for example, how radioactivity works: by nucleons tunneling out of the strong binding in the nucleus). You can make a trap good (low probability of escape) but never perfect (zero probability of escape).

                I don't really agree with this, or rather I don't agree with what you seem to be implying. While the performance of everything is going to be limited by quantum uncertainties, in many real world applications (including high precision optics and nanotechnology), the effect can be several orders of magnitude less than we would ever notice. I see no reason why storing light with 99.999999% transmission for several years would be impossible due to quantum uncertainties.

                But it's not that there is a quantum level that matches the wavelength of the light, but rather the Heisenberg indeterminacy principle basically allows for "blurring" of everything (the wavelength, the energy gap, etc.). So there is always a non-zero probability of interaction/absorption. Of course, the probability can be made very small. Impurities, as you note, tend to provide a wider range of possible absorption bands, so that the probability of one being close enough to the wavelength of the light is higher. (It's also worth remembering that absorption doesn't only occur because of energy levels associated with electrons bound to atoms: the degrees of freedom for molecular translation, rotation, and vibration also have quantum levels that can absorb light.)

                I'm pretty sure this is not the dominant

    • Perhaps offering a purely photonic battery.

      Which could then provide the necessary 1.21 jigawatts to the flux capacitor AND power the time circuits to boot...yeah it just might work.
      • If you don't know what a photonic battery is, or why it's sought after, you're stuck in the 80s.

        Thanks for demonstrating that Slashdot is News for Nerds, not necessarily geeks.

    • Re: (Score:2)

      by kmac06 ( 608921 )
      Some people are working on things like this. As another poster said, you can set up two mirrors, and have a beam of light bounce of them up to maybe a thousand times or so. With 99.99% reflectivity mirrors (which is close to as good as you can get, and can cost several thousand dollars) this gives you 90% overall transmission. If the distance between the mirrors is, say, 2 meters, than you have the light stored for 6 microseconds. Certainly not long on human time scales, but plenty long for computing time s
  • if they had just done a cursory literature search on the phenomenon, they would have realized that previous experiments on the phenomenon has produced disasterous results for the researchers, and jennifer aniston [wikipedia.org]
  • Isn't Hänchen German for chicken? That would make him Goos Chicken.

  • The Source (Score:3, Informative)

    by Anonymous Coward on Monday November 19, 2007 @01:06PM (#21409957)
    It would be nice if the "journalists" bothered to mention there's an article in Nature [nature.com].
  • Sounds neat because although the end goal is to process information at the speed of light, there are situations where light would need to be slowed down. Need to boot up your PC? Hit the light switch! Want to watch the OS compile? Use the dimmer switch!

  • There may be a prism on the dark side of the moon that produces rainbows... or so an ungodly amount of acid apparently led Pink Floyd to believe.

    • There may be a prism on the dark side of the moon that produces rainbows... or so an ungodly amount of acid apparently led Pink Floyd to believe.

      No, if you turn the album cover over, you'll see where the rainbow is mixed down to a coherent white ray, which travels to the front cover, where it diverges into a rainbow that travels to the back cover, where the rainbow is mixed down to a coherent white ray, which travels to the front cover, where it diverges into a rainbow that travels to the back cover, where the rainbow is mixed down to a coherent white ray, which travels to the front cover, where it diverges into a rainbow that travels to the back

  • Was over heard in the lab... (Score:4, Funny)

    by techpawn ( 969834 ) on Monday November 19, 2007 @01:12PM (#21410035) Journal
    This discovery is FABULOUS!
  • Good! Trip over the power cable quick and we'll never be bothered by those annoying creations Bungle, Zippy, Aunty and Telltale ever again.

    Though in hindsight that might of made more sense to the UK readers.....

  • [W]hen light hits an object or an interface between two media it does not immediately bounce back but seems to travel very slightly along that object, or in the case of metamaterials, travels very slightly backwards along the object.
    In other words, when light hits an object it does a moon dance.
  • Gay!
  • I skimmed the article and the conclusion I got was that for now this belongs with the earlier main page post about the top 10 snake oil products http://slashdot.org/article.pl?sid=07/11/19/1616248 [slashdot.org]. Nothing has actually been done to prove that this procedure is actually possible. This is an example of the worst in modern science. Publish of research via press release. There has been no Peer Review, this isn't being linked to from a scientific journal, it's a theory with no evidence to support it being po
  • Today we found it! The Rainbow Connection, for Lovers Deamers and You. La De da dee de da..

  • Like Hobbes said... (Score:3, Funny)

    by skyriser2 ( 179031 ) on Monday November 19, 2007 @01:37PM (#21410397)
    "If people could put rainbows in zoos, they'd do it."
    - Hobbes, Calvin and Hobbes
  • Then a unicorn came and kicked my ass. Fucking unicorns.

  • Great soon we will be able to catch (Score:3, Funny)

    by N3WBI3 ( 595976 ) on Monday November 19, 2007 @02:00PM (#21410735) Homepage
    That illegal immigrant 'Lucky' and confiscate his 'charms'
  • Props to the carebearstare tag, but why not Rainbow Brite? ....okay, i'm being silly.
  • There's this device that's been around for over a century. It's called a "camera". Since a rainbow is simply a band of color caused by refraction of light, capturing a record of that band of color on film (or digital media) is, in effect, captuting the rainbow itself.

    Now if you could catch the leprechaun [kuro5hin.org] that would be a different story!

    -mcgrew
  • Metamaterials? If they're not actual materials, then WTF are they?
  • Next on the agenda is to catch a falling star and put it in their pocket.
  • One of the best text adventure games I have ever played is T-Zero, and given this is /. I assume I am not alone.

    Apart from being extremely literary (puzzle references to Prufrock's love song among other things), this game was incredibly complex in it's movement across past, future and present. And the slow light flashlight was the icing on the cake - it illuminated an object with light from the objects past, enabling the player to view what the object WAS - it would be scary and exciting if this was a ste

  • to capture Oz too?

  • On top of the cliffs stood a reception committee.

    It consisted in large part of the engineers and researchers who had built the Heart of Gold - mostly humanoid, but here and there were a few reptiloid atomineers, two or three green slyph-like maximegalacticans, an octopoid physucturalist or two and a Hooloovoo (a Hooloovoo is a super-intelligent shade of the color blue). All except the Hooloovoo were resplendent in their multi-colored ceremonial lab coats; the Hooloovoo had been temporarily refracted into a

  • Read the article, it's a theory. They didn't actually build it. They just proposed it. to really do it, they need a real multispectrum transparent material with a negative index of refraction. (Same thing they need to build an invisibility chamber. Can you say "Unobtanium"?)

    Experimental physics is littered with beautiful theories that never worked in practice.

    Show us the trapped rainbow, please.
    • Heh... I love the irony in your request; If they show you the trapped Rainbow, it's obviously not trapped.
  • Angels released the waters from above and from the deep when God's bow, which used to serve as a reminder that He wouldn't flood the Earth again, was captured by misguided scientists.

    "We didn't think we were doing anything wrong; I mean, the rainbow looked neat. It's not like we had any arrows big enough to shoot from it."

    "How were we to know we'd be the ones to make 'Waterworld' a reality?"

    Thankfully, God quickly scolded the Angels in question and reset His bow in the heavens. The scientists were s
  • I hope they catch a Unicorn next! So I can prove them all that I wasn't crazy, right Jenny? Jenny doesn't like electroshocks, right Jenny? Jenny... jenny
  • Looks like we're close to having the Light Saving Brick [google.com] (watch the video).

    Peter, you've lost the news! [google.com]

    And with that, I've lost our American audience...
  • It would have been nice to see what the trapped rainbow looks like. It is too bad the article does not contain an actual picture of it. This seems quite common of many articles of some fascinating discovery, heavy on hype, but not providing much data or depictions of it actually in action.
  • How does slow light speed up the internet? wouldn't slow light take more time to cross tubes thus slowing the internet? or is my understanding of "slow" that whack?

  • And for their next project (Score:3, Funny)

    by dkleinsc ( 563838 ) on Monday November 19, 2007 @05:51PM (#21413833) Homepage
    Great: Now capture a Hooloovoo (a hyper-intelligent shade of the color blue).
  • We're only a couple proofs away from Kyle having to suck Cartman's balls.
  • What does it mean that I read the title as "Scientists Crap a Rainbow ... in your mind!"?

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