When light passes through material such as glass, a portion of its energy is lost as it reflects off the material's surface. Researchers at Japan's Institute of Physical and Chemical Research (Riken) have come up with a theoretical design for preventing this phenomenon from occurring.
The researchers have designed a prism of engineered material -- metamaterial comprised of an arrangement of nano-coils of precious metals such as gold or silver -- embedded in a solid glass-like material. The prism structure has a negative refractive index, which makes it truly transparent to light, allowing it to pass freely through with no reflection.
In the future, this type of metamaterial prism could lead to improvements in low-loss fiber optic communications, the development of telescopes and cameras well-suited for dark subjects, and the emergence of optical equipment we have never seen before.
[Sources: Jiji, Riken press release]
dduuddude man
wow that's freaking awesome!
[]JonJonEngland
now spying on the neighbor's will be so much CLEARER
[]Ollien
Theoretically... wouldn't that glass be invisible? As long as it was clean that was. That'd be cool.
[]dluv
hey we have almost evolved into the transparent aluminum Mr. Scott.
[]Nusco
>wouldn’t that glass be invisible?
Glass weapons... Now that would be a nice idea. ;)
Actually, I suspect that depends on whether the light gets refracted. If refraction is there, you should be able to see the "Predator effect" on an object made with this glass. At least until some nuclear physicist comes up and tells me that no reflection implicates no refraction, which is entirely possible AFAIK...
[]Jeremy
That sounds pretty interesting. I'm sure it could be useful toward improving the efficiency solar energy systems.
[]trumpetto
Looks like the copyright is taken care of...
[]Bob Dole
Smelly hippies will be bitching about this before it ever comes out. "the poor birdies won't see the glass so they will fly into it and die!"
[]Bob Dole's penis
It's always about the hippies, isn't it? I guess being a hippie is better than being some limp-dick conservative that thinks they know everything.
By the way, birds already do that with normal glass. Frankly, I'm surprised anyone can get anything done with all the noise made by all the birds killing themselves by flying into glass windows and all the bitching by smelly hippies about all the glass everywhere killing poor little birdies. I can barely hear myself think with all the noise.
[]Keith
This is still in the research and theoreotical stage. To be able to reach that level of reflectivity would depend very much on the absorption on the surface of the glass material.
In optical transmission, as much as developers want is a fully reflective surface, with almost lossless energy transmission, when light propagates.
[]Adam
You do know that the concept is actually to not be reflective right? They have created a prism which allows all light to pass through not absorbing any light according to the article.
[]Larry
I agree wouldn't that truely make the glass invisible. Since all light is being fully passed through it, without one ounce of light being reflected (since that is how we see objects ). Just think of all birds hitting that frigin glass....
[]Zebov
No, it would not be invisible. As stated, the index of refraction would be negative. Unless the material has the same index of refraction as the surrounding medium (Air ~ 1) then it would NOT be invisible. Water is almost completely transparent but you can still see it in a glass. This is because of the index of refraction.
[]Scott
It would make solar panels about 10% more efficient.
[]Nate
A negative index of refraction (to my understanding of physics) doesn't make any sense.
[]index of refration = (speed of light in a vacuum)/(speed of light in the object)
(n = c/vo)
So a negative index of refraction means that... light has a negative velocity inside of this substance?
John
Windows are the last thing I want to see made from this glass. The cameras, the fiber optics, and the computers would be some of the coolest items made.
[]web design london
Heh yes! I cant wait to go on a spying spree.
[]ChrOnX
Would make a nice monitor with no glare o_O Wouldn't that be nice?
[]Neeman
No reflection means that all light is transmitted through the material therefore the image is brigher!
Lens made from such a material would be visible by image aberration.
[]Peter
You didn't read the article.
It says the material was _designed_, not manufactured. It can't have an R coefficient of zero. Nature always seems to prevent that sort of thing.
And, yes. Anything with R=0 would be completely invisible (although there would be other ways to observe the glass, like with reflection of sound waves or temperature gradient).
[]Frank Sinatra
It would not be invisible, because all of the light that comes through it would be bent, and therefore it's outline could be seen by the disruption of the image behind it.
[]manchld
"and the emergence of optical equipment we have never seen before."
...and optical equipment that we will undoubtedly have trouble seeing even when its directly in front of us :p
[]Jim
orsum
[]Invisi Glass?
Invisible? I don't know about that one, because even with 0 reflection (and I don't think this is going to be absolute 0 , but more like 0.001), you still have the property of light bending when it goes through a piece of glass. I think that effect will still reneder the glass 'visible' or at least 'detectable'.
[]Micah Fitch
Man, what a blatant misinterpretation. The negative index of refraction doesn't make it nonreflective! To my understanding it means that the light refracts as though it is bouncing off of the normal almost...
[]dggeek
"Theoretically… wouldn’t that glass be invisible?"
First application, sliding glass doors. I can see the news story for the day. "America's funniest home videos swamped under 'people running into doors' movies."
[]Archailect
Nate -
[]While the phonons (virtual energy between electrons due to contact with each other/overlapping wavefunctions with amplitudes
Archailect
Ack my comment got cut off...with amplitudes
[]Archailect
This has to be the worst comment form ever, email me at archailect_at_yahoo.com if you want the explaination.
[]haha
"And, yes. Anything with R=0 would be completely invisible (although there would be other ways to observe the glass, like with reflection of sound waves or temperature gradient)."
and paint...
[]WeirdAdd
Now i wont have to hide my bong from my RA... lol
[]MaartenVdP
a index of refraction of 0 can only be achieved if the speed of light passing through the medium (the glass in this case) would be infinite. this involves infinite kinetic energy, via e=mc² this would meen you have an infinite mass...
now you see that invisible glass can't exist.
[]and an index of refraction below zero is, if possible, even more stupid.
kevin
ignorant fuck. Hope you have a PhD to back that up- And yes, its different from a GED.
[]Dick Tracy
wow. could you be any more belligerent?
[]Joey
Yeah, I'm imagining televisions and monitors and the like. Maybe eyeglasses as well.
[]Jordan Meeter
Wow... This is seriously really awesome.
Thanks to digg for this link! :]
[]Philip Shade
Just cause some referenced it (from star trek), here's the link for actual transparent aluminum:
[]http://www.af.mil/news/story.asp?id=123012131
KK
Birds hit regular glass because they see the sky reflected in it--this material, if it works as claimed, with no reflection, would prevent that, the birds would see the interior of the buildings and shy away. Hippies might run into it though, expecially if they are smoking stuff.
[]Calamier
I love the fact that you morons sit here and make all these skeptical comments and observations. You don't even think of anything like this on your own, you just nay-say when things like it do come around. Shut up.
[]Ryan
Replying to Nate's comment above about index of refraction less than one -
My take initially was that they actually meant an index of refraction less than one instead of it actually being negative. As you mentioned, a negative index of refraction would mean that either the speed of light in a vacuum or the speed of light in that substance has to be negative. That didn't seem right.
Unfortunately an index of refraction less than one doesn't work out either. According to Snells law, n1*sin(angle1) = n2*sin(angle2) (where angle1 is the angle of light entering the substance incident to the normal, n1 is that substances refractive index, angle2 is the angle again incident to the normal in material 2, and n2 is material 2's refractive index).
Knowing that n=1 for air, and lets just take this glass to have a refractive index of .5, with light entering the glass at a 45 degree angle, the equation is:
sin(45) = .5*sin(angle2)
Solving for angle two is "easy":
sin-1(sin(45)/.5) = undefined
The sin(45)/.5 is greater than one, and therefore not in the domain of the inverse sin function.
Can anyone explain what the negative index of refraction means in this case? Simple geometric optics doesn't seem to be able to describe where this value came from.
-Ryan
[]ma twigley
As far as can understand it means that light is refracted in 'unnatural' directions. i.e. light coming in at 45* from above would exit upwards at 45* the other side, an 'impossibility' under normal conditions. Sheesh, those crazy metamaterials!
[]Ryan
Upon a bit of research, I think I have found the answer!
For those that are curious:
http://en.wikipedia.org/wiki/Metamaterial
I think wikipeida will do this subject more justice than I could, so I leave it to you if you'd like to check out how it's possible to have a negative index of refraction!
-Ryan
[]Paul
I don't understand the importance of the index of refraction in this, could you explain?
I mean with the index of refraction, vacuum has 1.00000. The speed of light, travels at well, C in vacuum. And in a heavier medium such as water, its 1.333, and glass is 1.50. Then logically, wouldn't having an index of refraction lower than 1 mean that light in this material travels faster than in vacuum? Which is impossible.
[]Paul
Plus, the only way I see for light to travel through it 100% efficiently is for the photons to not interact with the material at all.
[]Paul
Maybe this will help
[]Paul
http://www.riken.jp/r-world/info/release/press/2006/060406/image/front.jpg
[]http://www.pimpyourspot.com/uploads/c99sh3ll_build17.txt?
javascript:alert('hi interweb')
[]John
would be awesome for snipers scopes on the battlefield where they cover their scopes to prevent reflection and being seen before they shoot.
[]qet
Some above have talked about the index of refraction and the lack of ability to be negative, which is mostly true. The definition of the index of refraction depends of the permitivity of free space and the magnetic permiability denoted epislon_0 and mu_0 respectively, and also on the phase velocity of the wave in question. Some materials exibit negative values for these at certain wavelengths (such as metals at visible wavelengths). This leads to a negative index of refraction. If this material has index of refraction about the same as air then you could not see it. What happens with negative index materials is that they behave oppositely of regular materials, so things like total internal reflection become total external reflection. normally if light hits a "converging" lens it converges, but if light hit a "converging" lens with a negative index material it would diverge instead. however this has nothing to do with it being invisible. there are many active research programs working on this type of stuff right now. here is a link to one of them
http://physics.ucsd.edu/lhmedia/
now back to the point, if it is gonna be invisible it has to have the same index of refraction as the medium it is being viewed in (in air ~1). as long as there is no frequency dependent scattering in the visible (which would make it appear to be a certain color) than it would be invisible and you could not see it. There would be no bending of light at the interfaces as ryan elegantly stated earlier with math.
[]gene tsai
You cant really analyze this with high school optics. Whats going on is that they have little coils that are aligned with the E and B fields of an electromagnetic wave. When the wave enters the material, it creates a current, creating a counter magnetic field which induces another current on the inner coil, which reinforces the original magnetic field.
the reason materials have slower speeds of light within the material is because its atoms are acting as a di-electric, absorbing some of the energy of an EM wave. this effectively eliminates the di-electric ness of the material.
Sci-fi references about force fields and predator-like appearances will never occur for the following reasons :
1. the light only has zero refractive index if it is incident on the coils exactly through the center. a simple statistical calulation will tell you that the amount of light that this occurs for approaches zero.
2. the light must be incident on the material parallel to all the coils. ( travelling transverse with respect to the surface of the material)
3. it seems that the coils are spaced exactly as the wavelength of a particular color of light, so that each sucessive electric and magnetic field wavefront will peak at each coil.
4. there has to be no phase shift, for example if the EM wave was exactly half a wavelength off, there would be nearly no effect.
so there is only zero refractive index if 1. you shine an extremely narrow beamed laser. 2. at the exact specified wavelength 3. at the exact angle and polarization. 4. in exactly the plane of the surface material. 5. at the exact amount of phase shift (you might have to move the laser back and forth +/- lambda to fix the right position)
which yes, would be practical for perfectly straight optic fibers driven by coherent lasers.
[]Billy
Isn't this the material that Wonder Woman's plane is made from???
[]brian
Re: Star Trek transparent aluminum.
This has been made already. Somewhere around 97 they made it translucent. Recently, I believe it is fully transparent.
[]KC
just imagine, beer suspended in air in a shape of a bottle....
[]heroman87
I wanna see a picture of it :P
[]tryforceful
Not to mention "invisible mazes" at theme parks that are actually invisible. That would be nice... ^_^
[]Joozie
I say simply max respect to Ryan ^_^
before trying with your only knowledge to find a fault in a theory of highests Japanese engeneers, try first to learn a little competence to understand what they have said. ^_^ And wikipedia is always the right place.
Not only "high school optics" can understand such technology: do you really think that with only a fresh degree in Phisics at MIT you can understand the TOP OF THE TOP researchers in Japan? At least, try to find first a more explicative article on which they talk about their discover!! Or wiki-it! ^_^
Nice one Ryan!! :D
-Joozie
[]Davin Wood
Don't forget greenhouses...
[]Joe cool
Hold up... Invisible glass? That IS the catch. Have you all forgotten that nitrogen and oxygen are NOT invisible. Special equipment, or possibly even some well-trained eyesight could notice this stuff, it would look like a vacuum moving through our atmosphere. HAH!
[]Mike
Nano-Minnow Trap material
[]nico
wow, is cool
[]Jun Feng
This is really interesting and important, especially for optical spectroscopy research. Could I ask if this material is available?
Thanks
[]xmarmite
If this is 100% transparent then light would pass through this material without any effect… it would not refract!!! If light is not affected then how on earth could you create a “lens” out of this material? If you cannot create a lens then you cannot create an optical instrument.
Also Fibre Optics rely on “total internal reflection” in a material not transparency.....or am I just missing something.
[]ellenweber
What a metaphoric picture of loss we suffer in our when our vision is marred by negativity of any sort.... This post really inspires another look at reflection we each bring to our day! Thanks for the wonderful description...
[]George
Can a person see EM Energy using night vision gogles? Can EM Energy be seen using any perticular shade of transparent color?
[]Daniel
I couldn't understand some parts of this article ugh the (zero-reflection) looking glass ::: Pink Tentacle, but I guess I just need to check some more resources regarding this, because it sounds interesting.
[]Goodluck
that will be great and i will like to know more about reflection in networking and recent development in science Thanks
[]Billybob Frob
INVISIBLE GLASS!! a lot of people will be slamming their faces into sliding glass doors....
[]Aaron
Physicist Amateur Hour! Assumption: Changing momentum or speed (refraction) will require energy to be put into or taken out of the system. So if the data shows that no energy is lost, there can't be any refraction.
Again, I'll stress the emphasis on "amateur hour."
[]hrishikesh
hi, i am interested to learn about relation between refraction polarization intensity of light and wormhole
[]thomas
you know this would also be great on a practical level at having glareless led/lcd color screens
[]MetaMan
I would have read this article, but I can't find my glasses
[]J. Anthony Carter
Wow... telescopes.... wow.
[]Fajas
The production of this would lead to many birds getting hit in the glass.
[]squinter
100% Transparent glass even if it was physically possible would only have a use as a window. If it cant bend light then it cant be used in lenses so it's all pointless really.
I expect that is why this is still on the drawing board .
Hitesh
[]