View Full Version : Scientists ponder invisibility cloak

05-28-2006, 10:18 PM


WASHINGTON -- Imagine an invisibility cloak that works just like the one Harry Potter inherited from his father. Researchers in England and the United States think they know how to do that. They are laying out the blueprint and calling for help in developing the exotic materials needed to build a cloak.

The keys are special manmade materials, unlike any in nature or the Hogwarts School of Witchcraft and Wizardry. These materials are intended to steer light and other forms of electromagnetic radiation around an object, rendering it as invisible as something tucked into a hole in space.

"Is it science fiction? Well, it's theory and that already is not science fiction. It's theoretically possible to do all these Harry Potter things, but what's standing in the way is our engineering capabilities," said John Pendry, a physicist at the Imperial College London.

Details of the study, which Pendry co-wrote, appear in Thursday's online edition of the journal Science.

Scientists not involved in the work said it presents a solid case for making invisibility an attainable goal.

"This is very interesting science and a very interesting idea and it is supported on a great mathematical and physical basis," said Nader Engheta, a professor of electrical and systems engineering at the University of Pennsylvania. Engheta has done his own work on invisibility using novel materials called metamaterials.

Pendry and his co-authors also propose using metamaterials because they can be tuned to bend electromagnetic radiation - radio waves and visible light, for example - in any direction.

A cloak made of those materials, with a structure designed down to the submicroscopic scale, would neither reflect light nor cast a shadow.

Instead, like a river streaming around a smooth boulder, light and all other forms of electromagnetic radiation would strike the cloak and simply flow around it, continuing on as if it never bumped up against an obstacle. That would give an onlooker the apparent ability to peer right through the cloak, with everything tucked inside concealed from view.

"Yes, you could actually make someone invisible as long as someone wears a cloak made of this material," said Patanjali Parimi, a Northeastern University physicist and design engineer at Chelton Microwave Corp. in Bolton, Mass. Parimi was not involved in the research.

Such a cloak does not exist, but early versions that could mask microwaves and other forms of electromagnetic radiation could be as close as 18 months away, Pendry said. He said the study was "an invitation to come and play with these new ideas."

"We will have a cloak after not too long," he said.

The Pentagon's Defense Advanced Research Projects Agency supported the research, given the obvious military applications of such stealthy technology.

While Harry Potter could wear his cloak to skulk around Hogwarts, a real-world version probably would not be something just to be thrown on, Pendry said.

"To be realistic, it's going to be fairly thick. Cloak is a misnomer. 'Shield' might be more appropriate," he said.

05-28-2006, 11:13 PM
that woudl be sweet

05-29-2006, 01:24 AM
They already made one. They just can't find it.

Homer's Ghost
05-29-2006, 02:26 AM
They already made one. They just can't find it.

05-29-2006, 02:37 AM
Personal cloak?

Sweet :evil:

05-29-2006, 03:21 PM
Husbands have been waiting for this technology for decades. :lol:

05-29-2006, 06:05 PM
Invisibility cloak ... oh the double edged sword. Would it be fun for the average joe and especially the military. You bet. But on the negative side, Burglars, rapists, murders, etc. all might find it interesting also.

05-29-2006, 08:50 PM
Invisibility cloak ... oh the double edged sword. Would it be fun for the average joe and especially the military. You bet. But on the negative side, Burglars, rapists, murders, etc. all might find it interesting also.

Yeah, but the downside of the technology is that they can't fire their weapon until they de-cloak. ;)

05-30-2006, 11:00 PM
Would there be a dagger dangling? ;)

Johnny Footstool
10-19-2006, 05:10 PM
That was fast...


Scientists Create Cloak of Invisibility

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Oct 19, 4:50 PM (ET)


WASHINGTON (AP) - Scientists are boldly going where only fiction has gone before - to develop a Cloak of Invisibility. It isn't quite ready to hide a Romulan space ship from Capt. James T. Kirk or to disguise Harry Potter, but it is a significant start and could show the way to more sophisticated designs.

In this first successful experiment, researchers from the United States and England were able to cloak a copper cylinder.

It's like a mirage, where heat causes the bending of light rays and cloaks the road ahead behind an image of the sky.

"We have built an artificial mirage that can hide something from would-be observers in any direction," said cloak designer David Schurig, a research associate in Duke University's electrical and computer engineering department.

For their first attempt, the researchers designed a cloak that prevents microwaves from detecting objects. Like light and radar waves, microwaves usually bounce off objects, making them visible to instruments and creating a shadow that can be detected.

Cloaking used special materials to deflect radar or light or other waves around an object, like water flowing around a smooth rock in a stream. It differs from stealth technology, which does not make an aircraft invisible but reduces the cross-section available to radar, making it hard to track.

The new work points the way for an improved version that could hide people and objects from visible light.

Conceptually, the chance of adapting the concept to visible light is good, Schurig said in a telephone interview. But, he added, "From an engineering point of view it is very challenging."

The cloaking of a cylinder from microwaves comes just five months after Schurig and colleagues published their theory that it should be possible. Their work is reported in a paper in Friday's issue of the journal Science.

"We did this work very quickly ... and that led to a cloak that is not optimal," said co-author David R. Smith, also of Duke. "We know how to make a much better one."

The first working cloak was in only two dimensions and did cast a small shadow, Smith said. The next step is to go for three dimensions and to eliminate any shadow.

Viewers can see things because objects scatter the light that strikes them, reflecting some of it back to the eye.

"The cloak reduces both an object's reflection and its shadow, either of which would enable its detection," Smith said.

The cloak is made of metamaterials, which are mixtures of metal and circuit board materials such as ceramic, Teflon or fiber composite.

In an ideal situation, the cloak and the item it is hiding would be invisible. An observer would see whatever is beyond them, with no evidence the cloaked item exists.

"Since we do not have a perfect cloak at this point, there is some reflection and some shadow, meaning that the background would still be visible just darkened somewhat. ... We now just need to improve the performance of cloaking structures."

In a very speculative application, he added, "one could imagine 'cloaking' acoustic waves, so as to shield a region from vibration or seismic activity."

Natalia M. Litchinitser, a researcher at the University of Michigan department of electrical engineering and computer science who was not part of the research team, said the ideas raised by the work "represent a first step toward the development of functional materials for a wide spectrum of civil and military applications."

Joining Schurig and Smith in the project were researchers at Imperial College in London and SensorMetrix, a materials and technology company in San Diego.

The research was supported by the Intelligence Community Postdoctoral Research Fellowship Program and the United Kingdom Engineering and Physical Sciences Research Council.

10-19-2006, 10:10 PM
Now if they could just get to work on perfecting that Jedi mind trick...These aren't the droids you're looking for.

Chip R
10-20-2006, 09:22 AM
Now why do I think this guy is involved?


Johnny Footstool
10-20-2006, 09:38 AM

10-21-2006, 12:41 AM
I know there is a thread here, but I can't see it.

Doc. Scott
10-22-2006, 12:43 AM
They better not give this to any soldiers. They'd become visible the minute they made an attack. But as long as they didn't, enemies would strike at a -4 penalty.

10-22-2006, 08:29 AM
Sigh. I already invented this years ago. Gosh.