Cloak on, cloak off: Simulations show how light interacts with the cross section of the cloaking device. When it’s uncloaked (top), light is reflected off the object. But when it’s cloaked (bottom), light is guided around the object and anything within it.
Birck Nanotechnology Center, Purdue University
A new theoretical design using nanowires provides a way to hide devices from visible light.
A hairbrush-shaped device has been theoretically designed that would use bristles made out of nanowires to bend light around it, rendering the object invisible. The researchers who came up with the design say that it's the first practical design for an "optical cloak" to work in the visible spectrum. They are now working on building an actual device based on their calculations.
Although still only a theoretical design, it is the first to show how a recently discovered cloaking effect could be made to work for all wavelengths of visible light, says Vladimir Shalaev, a professor of electrical and computer engineering at Purdue University, in West Lafayette, IN, who led the research effort.
"It sets out a road map for building these sorts of structures," says John Pendry, a professor of theoretical physics at Imperial College London, U.K. Besides making it possible to turn things invisible, the work could lead to ways to create heat shields by bending infrared light around objects, he says. Pendry's initial research led to last year's creation of the first working cloaking device, which operated in the microwave range. (See "Cloaking Breakthrough.") This latest work now shows a way to extend this into the visible-light range, says Pendry.
To become invisible, an object must do two things: it has to be able to bend light around itself, so that it casts no shadow, and it must produce no reflection. While naturally occurring materials are unable to do this, a new class of materials called metamaterials is now making it possible. (See "TR10: Invisible Revolution.")
Bending light around an object requires a material to have a negative refractive index. The refractive index is a property that dictates how light passes through a medium; it's the reason a stick will look bent when placed in water. If water had a negative refractive index, it would make the stick look as though it were bending back on itself.
Last year, Pendry demonstrated that it is theoretically possible to design structures of very thin conducting wires that could have an effect on the electric and magnetic fields of microwaves, causing them to bend in unnatural ways such as this. This theory was later backed up by experiments carried out by David Smith and David Schurig at Duke University, in Durham, NC.
But repeating the success for visual light seemed to present problems. For one thing, making the design used by Smith and Schurig work for visible light would require components just 40 nanometers in size.
What about non-mechanical structures?
I haven't read the report (I wish I could) but I wonder if interference patterns of compression waves (i.e. ultra-short wavelength sound or something like it) could provide a tunable structure to produce the same effect.
it is possible to make things invisible,we have already things that is partialy invisible like glass,water,air. to make object invisible one another method is thier that is
light ray falling one side of the object should be reproduced on the other side of the object, using a system capable of light sensing and emitting, maintaining that properties of the ray like wawelength,intensity,diretion by doing this we can see through the object that means the object is invisible.
tharas bulpa
to successfully do that, the object has to be 100% surrounded by a camera lens, in order to capture every angle. and, it also has to be 100% surrounded by some sort of display.
that's not really possible, as far as i know.
Even if it was only invisible from one side (could be somewhat useful). You would still have to carry a bunch of light recievers and emitters and computers to analise the light and reproduce it. And it would be useless if the cloaked object and the observer object are moving relative to each other.
Beemarao, I think you might be confusing invisible with colorless in this instance. You said that water and glass are somewhat invisible. I'm not trying to say you are wrong, because its your opinion, just saying that water and glass reflect light, which is in contradiction to the definition of invisibility. However, water and some glass do allow light to pass through them, which is where the colorless aspect comes in (instead of reflecting all colors making them white)
This is a intresting idea and a good innovation. If becomes fully successful it is unknown for what good purposes it will be used.
www.browsetoknow.blogspot.com
What would be done with such a technology? Well, I have been working on concepts for invisibility for years. I always knew the "Invisible Man" concept would not work. Nor would anything involving reproduction of images. I see it as being able to control Ultraviolet rays. But one concept I have yet to see explored is to approach the problem using Sound Cancelling technology. Any thoughts on this?
Also, why does every fictional Invisible Man end up miserable? Hell, there are too opportunities for fun, hunting down bad guys or just being able to walk about, undetected and mess with people. That would never get old.
Dr. Spook
That work is excellent and very interesting, however I would also show that a recent work indicates that Perfect Invisibility Devices using isotropic media are possible. Furthermore, the new design allows to get around the Nachman theorem using these isotropic materials.
you can learn more here...
http://invisibility.research.googlepages.com/
http://techon.nikkeibp.co.jp/article/NEWS/20080416/150549/?ST=nano
can u tell me pls what formular ihave to use
really interesting.
Maybe invisibility means absorbing light at front & emitting at diametrically rear.
Hence a person looking at invisible thing would just only be able to see through.
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Cesar
1 Comment
Now you see it, now you don´t
Ver interesting and innovative
Reply
louppl72001
1 Comment
Re: Now you see it, now you don´t
Can't help but wonder, is our technological advancement determined by the ideas and imagination of scifi writers or were they merely predicting our future.?
Reply
martwill38
9 Comments
Re: Now you see it, now you don´t
I think a Harry Potter style "invisibility cloak" is far from likely based on this research. Since it appears to operate over only a narrow range of frequencies, to make it work over a wide range might involve many layers, each operating at different light wavelengths, so as to cover the visible spectrum. But in stealth applications, you would also want radar invisibility at all microwave frequencies that are now, or could later be, used. How would you isolate the layers and prevent some from reflecting the light before it reached others?
Present stealth mechanisms work mainly by absorption and reflection at odd angles not likely to be received by the radar transmitter.
Reply
Aiden!
2 Comments
Re: Now you see it, now you don´t
Probably not Harry Potter style, but something more akin to the cloaking in Ghost in the Shell, where the cloaked object/person is still faintly visible.
Reply
montezuma2004
2 Comments
Re: Now you see it, now you don´t
Good question, but I wonder if technology is advancing much faster than our ability to adapt to it.
Reply
swordfishdata
7 Comments
Re: Now you see it, now you don´t
I personally think that a person's ability to adapt is limited only by that person's willingness to do so. If one insists upon sticking with what one has always known, one deserves to be left in the dust. (no offense intended to those who find their employment displaced by technology, but nothing happens overnight. If they don't see something coming, it's partially their fault.)
Reply
McMillan968
38 Comments
Re: Now you see it, now you don´t
Not trying to steal your thunder but ever since Buck Rogers was patrolling outter space and men were landing on the moon science has ALWAYS strived to catch up.A lot of times working off sci-fi ideas.
But we are definitely in a period of tech going ahead of what we are ready for,hope it stays that way too!!!
Reply
fixerdave
28 Comments
Re: Now you see it, now you don´t
I've always considered the purpose of art to reflect on our condition or predict new possibilities. With this knowledge, we can adjust the course of our development. SciFi, in an age of science and technology, is obviously going to have the greatest effect on our future. Life imitates art, or avoids it; that's arts job, be it Soylent Green or Blade Runner, Romulan cloaking devices or tri-corders. Some imagined stuff comes fast - other stuff never seems to get here.
On the other hand, sometimes, stuff just comes from the lab, stuff that nobody ever thought of before. I wonder if anyone has done acceptance studies comparing how populations deal with art-imagined verses "straight from the lab" generated technology. Now, that would be interesting.
Now, could you imagine some kind of cooling device based on this technology? Something that could radiate infrared but not absorb it, even on a sunny day. Art has prepared us for disappearing ships or people, not better air conditioners.
Reply
centaur8
3 Comments
Re: Now you see it, now you don´t
Whether life imitates art, or art imitates life, or life imitates life, the common strand is people coming up with new ideas, whatever field they are in. New ideas have come out of all kinds of people, even "from the mouths of babes and jokers . . . "
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