Technology Review - Published By MIT
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Friday, May 26, 2006

Cloaking Breakthrough

Continued from page 1

By Duncan Graham-Rowe
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The reason is that, to produce the cloaking effect, the substructures of the metamaterials must be smaller than the wavelength of light being redirected. That's currently feasible for microwaves, which have a wavelength of about three centimeters. But redirecting visible light, which has a wavelength of around half a micrometer, or half a millionth of a meter, would require metamaterials with structures engineered at the molecular level. "We would like to do it on a molecular scale, but nanoengineering is not yet up to it," says Pendry. Recent developments in nano metamaterials, however, could speed the development process up.

For now, then, the prototype cloak consists of arrays of millimeter-sized copper rods and C-shaped rings embedded in a composite fiber board, much like the kind of printed circuit boards that normally house computer chips. Both the rods and the C-rings are capable of passively creating electromagnetic fields when exposed to microwave radiation. When oriented just right, these components can specify the path that the radiation will follow.

There is also another application for cloaking, says Schurig: it can be used as a kind of shield. "Sometimes you want to protect or isolate things from the electromagnetic spectrum," he says. For example, cloaking could be used on space probes to protect sensitive equipment from cosmic radiation.

But there is a catch. While any cloaked object would be invisible, it would also be blind within the cloaked frequency range, since any light directed toward it would be rerouted around it. In the case of a radar-cloaked plane, this should not be a major problem, says Schurig. The pilot would be unable to use radar, but she could still navigate visually.
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Comments

  • [no subject]
    Guest (Nauman) on 05/26/2006 at 12:00 AM
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    Seems to be the age of breakthroughs doesn't it??
    Rate this comment: 12345
    • WWIII, what Caused it?
      Guest (Slpgdragon) on 05/26/2006 at 12:00 AM
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      We venture into fields that are going to threaten global peace. Things like this should never be placed on the web for National Security's sake. When world fores who already are just looking for a reason to pick a fight with us we come out with something that gives them incentive. Imagine the implications of this technology, we could hide space weapons in plane site. We could shield military troops movements at will. The list is endless. And to think how this technology could escalate problems if it fell into the wrong hands. Being able to walk into a Bank anywhere in the world masking yourself, move over Casper we have real Ghosts now we don't need Hollywood!!!! I mean even the 1998 version of the movie the Invisiable Man as well as the version due to come out soon proves we do not demonstrate the ability to control this kind of techonology if placed into the wrong hands.
      I think i am going to build my next home OFF PLANET, and get away from this ignorance.
      Rate this comment: 12345
      • Cloaking... futures
        Guest (George) on 05/26/2006 at 12:00 AM
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        Good luck on your new planet.
        If one always looks at the "dark side" of things, why bother getting up in the morning?
        Everyone has the capability and the will to either do good or do evil. Most of life's greatest inventions and tools suffered from the same doom & gloom you are professing. An obvious sample would be nuclear power. It is marvelously benevolent source of power yet in the hands of those with evel designs... Does anyone really believe that there is somewhere someone who is trustworthy enough? Absolute power corrupts absolutely.
        I for one, will not stick my head in the sand and curse the darkness. Lets see what wonders man can produce and apply to humanity's betterment.
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      • home off planet
        Guest (The invisible cyberspace man) on 05/26/2006 at 12:00 AM
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        I guess we won't be "seeing you" in the future....Did you "see" that on coming?? hehe...
        Rate this comment: 12345
      • ignorance?
        Guest (kevin) on 05/26/2006 at 12:00 AM
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        If you move to a new planet, I suppose you would want to keep things simple, like a hut made out of sticks, fire and good.  Oh, but following your logic (ignorance) don't make the sticks too sharp, it's liable to make others think about using them for warfare or don't let anyone know about the fire, they might burn someone.  People like you that want to stay in the dark of things and look at the negative of everything have no vision and prefer to go backwards instead of forward.  pitty!
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      • cloaking ignorance
        Guest (Brian) on 05/26/2006 at 12:00 AM
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        As much as this technology has primarily military use, it is just an improvement on stealth technology. I can't see it as an effective shield against cosmic rays for space vehicles as proposed in the article, as there is no particular need for a probe to be invisible to cosmic rays, just shielded. I cant imagine its peaceful use. However, if the cloaking technology could be applied to your spelling mistakes, your input might look a bit more thoughtful.
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        • Cosmic cloaking
          Guest (Remmon) on 05/29/2006 at 12:00 AM
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          You musn't forget that in other to shield against cosmic radiate, you need a LOT of heavy material, like lead. Assuming this material will still work in a thin coat, it would be like choosing between a super-thin full-body suit that allows you to breathe normally and protects against fire completely. Or using a tank to go through the fire.

          Weight is a major issue in space, at least untill we can start mining asteroids, this technology could easy save a massive amount of weight.
          Rate this comment: 12345
      • Ignorance. yeah right!
        Guest (German) on 05/26/2006 at 12:00 AM
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        For starters nobody picks the US just for the sake of it, becoming the global cop, interventionist, imperialist is what causes reactions, so in order to stop violence, the path is not to build taller walls or more powerful bombs, but to look for armonic ways to respect the way other cultures think, relate and govern themselves. What do you say about the teathrical fabrication now recalled as 9/11 that the US president put in place to be able to change the laws and practically control all americans' lives with their consent just for fear? it was a quick and easy victory for him, not so much for armonic relationships, democracy or all the values regarded in the American Dream. On the technology side, thank God our ancestors did not fear their heighbours could use stones to kill a brother or a sister or a son, because if so, we would still be just swiveling between tree branches.
        Rate this comment: 12345
        • [no subject]
          Guest (nanana) on 05/26/2006 at 12:00 AM
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          Is it just me, or do some many people think 9/11 was just a ruse? I mean... it has to be right? So many people dying... all for one person's own betterment. WRONG! The president wouldn't just condemn people the way they died, and he wouldn't want our economy to suffer just to "take control" Its all these extremist people who claim the president is a power fiend, and that Americans are the bad guys that ruin things. Oh, and German, if you are really from Germany, look at the pain Germany caused so many people from being all of those things you just mentioned, but not a global cop, more of a regional cop. At least Americans have the deciency to help rebuild destroyed cities, and protect people.
          Rate this comment: 12345
          • same old refrain
            Guest (kitk) on 05/27/2006 at 12:00 AM
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            sure, some folks think 9/11 was a ruse--caused by the usual suspects (add your favorite enemy group here, Jews, usually). the same folks who think the holocaust didn't happen, or was just another 'ruse'. respect other cultures? do they respect mine? my culture invents and discovers; teh cultures who hate that borrow technology to make shoe bombs.
            Rate this comment: 12345
            • off topic
              Guest (Aymeric) on 05/31/2006 at 12:00 AM
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              Hello guys? Aren't we a bit of topic? But since we are let me put in my two cents. German, it is easy to be all loving and peacfull when you have another country doing the jobs you do not want to pay for or do not have the guts to do it. And secondly, as long as we have people like Puting and the Chineese it is really stupid to not research as much into military application as possible. And also do not forget that the internet was largely made possible because of military funding/research. If our ancestors had not been aggressive and warlike we would still be swinging from trees...
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          • Re: 
            ZeroGeined on 10/31/2007 at 1:53 AM
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            Why is it that just because somebody is from Germany, they're automatically assumed to be Nazis? Germany is not a "white power", jew hating country. It is a democratic country just like most of the world. It was a large group of people that used the political process to their advantage and took over the country of Germany and used it for their purposes. Its ignorant dickheads like that that need to be shot. Go back to high school.
            Rate this comment: 12345
      • You'll need to invent a few things before going off planet
        Guest (Shawn) on 05/26/2006 at 12:00 AM
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        Following your train of thought, we should all go back to living in caves and hunting with rocks and sticks.  Most inventions and breakthroughs can be used for both good and evil purposes.  Why single that one out?  The computer you used to write your post on can just as easily be used to write a computer virus, or develop the plans for a new weapon.  Heck, some of the technology you'll need to live "off planet" will most likely be used for evil as well.  Try looking at all the good that technology and science has brought us.  There will always be bad people in the world who want to use technology or science for evil purposes.  If we stopped developing new technology and pursuing scientific breakthroughs, the bad people would still be here.  Your argument does not hold water in my opinion.
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      • then better live on himalayas
        Guest (dts) on 05/26/2006 at 12:00 AM
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        then better live on himalayas

        <a href="http://www.jobs.co.in">dts</a>
        Rate this comment: 12345
      • National Security's sake? come on...
        Guest (A1228D) on 05/26/2006 at 12:00 AM
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        First of all I can assure you that all the information contained in this page is NOT enough for someone to go and "cook" some metamaterials and cloak himself. Then, assuming you meant hiding weapons in plain sight (not in plane site) well, it is done nonetheless and, if you read carefully it works with microwaves. It is not very likely for us to go around looking for weapons with radars (it's much more likely for us to use visible light or, need be, infrared light). And last, check your references, I mean the invisible man MOVIE?, not even the book... I think you should check your own ignorance before passing judgement on researchers, is it only me?
        Rate this comment: 12345
    • theory
      Guest (mytonytiger) on 05/26/2006 at 12:00 AM
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      Almost anything is possible in theory. We'll just have to wait and see if it actually happens.
      Rate this comment: 12345
  • Spherical Structures Only!
    Guest (Bill) on 05/26/2006 at 12:00 AM
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    I can't see this working on anything but a perfect sphere.  The thickness of the material is sure to affect how much the light is refracted.  And if you don't have a perfect sphere then I don't see how you could make the light coming from every direction revert to its original path after bending through the medium.  I can only perceive that a perfectly uniform sphere would be able to accomplish this.
    Rate this comment: 12345
  • The Red Coats are Coming!
    Guest (jsd) on 05/26/2006 at 12:00 AM
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    For everyone worried about the US developing this to take over the world, look where the research was done.  Science lists the primary authors of the research from the Imperial College London and University of St. Andrews, U.K.  Some professors from Duke helped, but after reading all of the articles in Science, it looks like the UK did a lot of the research.
    Rate this comment: 12345
    • Dismal US science
      Guest (Skeptic) on 05/26/2006 at 12:00 AM
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      Who's surprised that non-US scientists are doing the work. Ours are too busy defending evolution from religious whackos and politicians...
      Rate this comment: 12345
      • Re: Dismal US science
        mtone on 04/11/2007 at 1:36 PM
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        No ours do not exist. We have to import ours becuase we are dumbing down our students with, as long as you feel good and have sex its ok programs while the rest of the world cares about knowledge.
        Rate this comment: 12345
      • Re: Dismal US science
        Mr_Phil on 04/11/2007 at 3:17 PM
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        well said... bladdy whackos, bladdy bush.
        Rate this comment: 12345
  • Doubter
    Guest (Dan) on 05/26/2006 at 12:00 AM
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    I'll believe it when I don't see it.
    Rate this comment: 12345
    • DON'T BE SO SURE
      Guest (HUSKSTANG) on 05/27/2006 at 12:00 AM
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      How do you know, Dan, that you aren't seeing it NOW?!!  Or should that be that you aren't not seeing it now?!  I'M SO CONFUSED!!
      Rate this comment: 12345
  • Why is this under Infotech?
    Guest (Sean) on 05/26/2006 at 12:00 AM
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    Did it just not fit in any of the other categories?
    Rate this comment: 12345
  • Speed of light is constant
    Guest (Peiman) on 05/26/2006 at 12:00 AM
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    Politics aside, after all even internet was developed for nuclear ww3 but look it now, porn and gambling aside.

    I have difficulty understanding the logic here, isn't the speed of light constant? So did light warped around the object or the space warped? The base of this theory is that light frame remains constant and the speed close to the sphere reaches infinity. Perhaps the analogy of water stream is more accurate as the speed remains constant but the light could flow on the surface of the object. If it is just a matter of passing through a material well glass, plastic and many other see through materials already do that, what is the big idea here?
    Rate this comment: 12345
    • Constant in context
      Guest (Rich) on 05/26/2006 at 12:00 AM
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      The speed of light depends on (the inverse of the squareroot of) two parameters (the electric susceptibility and the magnetic permeability) which are characteristics of a material. The limiting case for this speed is when these two values are a minimum which occurs as the material becomes a pure vacuum state. In a vacuum the speed is a maximum and constant as long as the material is constant. Matter always has a higher value for these two parameters and so the speed of light in matter is always less that that in vacuum - there are no known exceptions to this. It is possible to create materials in which the values of these parameters are very large and so you can significantly reduce the speed of light through those materials. Look up Snell's Law to see how this results in light "bending" as it passes from one material to another.

      Hope this helps. Cheers, rb
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    • No such thing asa constant
      Guest on 05/28/2006 at 12:00 AM
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      We haved proven with experimentation that the speed of light can be slowed down and sped up and with relativly little energy as with the meta materials it would still be incrediably difficult to assertain any time delay at the spped of light for such a small distance to travle IE a body tank plane sat or even a country.
      Rate this comment: 12345
  • THIS IS NOT real yet
    Guest (Mason) on 05/26/2006 at 12:00 AM
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    OK people let's put this in context. There is NO cloaking device. There are not plans to make any cloaking devices because, for the most part, the metamaterials that Pendry refers to exist in small amounts, on the nanoscale. Even on that scale they're not well understood. Talking about making an "invisibility cloak" from these materials.... well, that's VERY far  off.

    What annoys me is that Pendry gets published in Science for saying, basically, "hey here's this cool idea that COULD work, but I don't have any actual experimental work to support it." Great. If only we were all so lucky.
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  • I HAVE AN IDEA!!
    Guest (HUSKSTANG) on 05/27/2006 at 12:00 AM
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    Once this thing is perfected, let's cloak THE ENTIRE COUNTRY, thus hiding it from our external enemies and rendering the United States safe forever from foreign attack!!  We would have to, though, slightly change The Pledge of Allegiance to the Flag: "...one nation, under God, invisible, with liberty and justice for all."
    Rate this comment: 12345
    • I HAVE AN IDEA!!
      Guest (hymy) on 05/28/2006 at 12:00 AM
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      So if the US is invisible, does an mexican standing at the border see canada?
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  • What Does Cloaked Person See
    Guest (Norman) on 05/27/2006 at 12:00 AM
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    Isn't the cloaked individual blind to his environment since he receives no light from the environment.
    Rate this comment: 12345
    • [no subject]
      Guest (tommy) on 05/27/2006 at 12:00 AM
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      I think the person would cut eye holes in the cloak, derr.
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      • what a person would see
        Guest (bob) on 05/27/2006 at 12:00 AM
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        well thay would be blind to whatever type of wave is being bent. if it was designed for visable light one could simple use infa-red to see through the cloak.
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        • JOSE, CAN YOU SEE?!!
          Guest (HUSKSTANG) on 05/29/2006 at 12:00 AM
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          Only if he or she had a very strong telescope...otherwise I think that he or she would see the same thing that we see out of the backs or our heads!!
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      • no Tommy, thats not right
        Guest (Andrew) on 05/28/2006 at 12:00 AM
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        every wave that is absorbed by the human eye is one that is not bent around, so the respective opposite side would be shadowed. Also If there were just "eye holes"  light would be reflected off of the eye, making the appearance of floating eyes.
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    • Stealth Instead
      Guest (Myopic Cyclopse) on 05/29/2006 at 12:00 AM
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      Why not use a tuned Salsbury Screen or other absorber and go with stealth? It poses less tech hurdles and you can emitt compatable radiation on the down-wind side to fool the watchers. Sort of like active stealth.
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      • Stealth vs cloaking
        Guest (Remmon) on 05/29/2006 at 12:00 AM
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        Stealth is nice, for the longer ranges, where you're difficult to see anyways. Cloaking however lets you walk right up to someone, unnoticed.
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        • Cloaking
          Guest (Nauman) on 05/29/2006 at 12:00 AM
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          Is the "Proof of Principle" thing a big hype, or is there some substance to it?
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          • "Proof of principle" is what makes it worthwhile
            Guest (German) on 05/30/2006 at 12:00 AM
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            Having a "Proof of principle" is having an actual working artifact or in this case, a piece of the metamaterial that would cloak something. To use a comparison, Thomas Alva Edison proof of principle bulb was one made with an incandescent string that lasted less than 1 minute providing artificial light. It took more than 2 years in trial and error for him to find a suitable string that lasted long enough for it to be commercial.
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    • The final paragraph of the article...
      Guest (ddb) on 05/30/2006 at 12:00 AM
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      "But there is a catch. While any cloaked object would be invisible, it would also be blind within the cloaked frequency range, since any light directed toward it would be rerouted around it. In the case of a radar-cloaked plane, this should not be a major problem, says Schurig. The pilot would be unable to use radar, but she could still navigate visually."
      Rate this comment: 12345
  • Polarized Sunglasses
    Guest (John Hewitt) on 05/29/2006 at 12:00 AM
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    Would I be able to see the invisible man on a boat if I had polarizing sunglasess?

    Sounds great, when you have perfected the technology and are ready for something challenging, I could always use some smart help designing my human powered flying apparatus and getting it to market quicker.
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