Scientists Trap a Rainbow

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."

Comments

In Rainbows

[Anonymous Coward]

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?

[Joe The Dragon]

Did they get the pot of gold as well?

Re:Did they get the pot of gold as well?

[KingSkippus]

Quite the opposite. The people who make Skittles candy are suing for patent infringement.

Re:Did they get the pot of gold as well?

[azav]

I heard they have had trouble separating the rainbow from the gold from the leprechauns, hence the low rainbow yield. On the positive side, there has been a bounty of yellow moons, purple horseshoes, blue diamonds and green clovers.

But they'll never get my Lucky Charms.

Re:Does this mean

[Thanshin]

that if Apple brings back the old logo they will rule the Intarweb tubes? No. The tubes are already clogged with bees.

Re:Scientists Trap a Rainbow

[kebes]

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 450, 397-401 (15 November 2007) | doi: 10.1038/nature06285. (See also summary comment box, doi 10.1038/450330a.)

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 Photonics 1, 41 - 48 (2006) doi: 10.1038/nphoton.2006.49.

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:Scientists Trap a Rainbow

[kebes]

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!