A 'cloaking device' -- it's all done with mirrors

May 13, 2009 By Bill Steele
Scanning electron microscope images of the cloaking device. Top: Light passes through silicon posts as it bounces off a deformed reflector. Varying density of the silicon posts bends light to compensate for the distortion in the reflector. Bottom: a close-up of the array of silicon posts, each about 50 billionths of a meter in diameter. Image: Nanophotonics Group

(PhysOrg.com) -- Somewhat the way Harry Potter can cover himself with a cloak and become invisible, Cornell researchers have developed a device that can make it seem that a bump in a carpet -- or, indeed, any flat surface -- isn't there.

So far the illusion works only at the , but the researchers suggest that the basic principle might eventually be scaled up for military and communications applications, or perhaps used in reverse to concentrate solar energy.

Devices that bend microwaves around small objects have previously been demonstrated, but this is the first cloaking device to work at optical frequencies, the researchers said.

The experimental device was built by Michal Lipson, associate professor of electrical and computer engineering, and colleagues in her Nanophotonics Research Group, based on a design by British physicists. It bends light bouncing off a reflective surface in a way that corrects for the distortion caused by a bump in the surface. Imagine controlling the light in front of a funhouse mirror so that reflections look perfectly normal, and the mirror looks flat.

A similar device has been reported by University of California-Berkeley researchers.

On a silicon wafer, Lipson's group made a tiny reflector about 30 microns (millionths of a meter) long with a 5-micron-wide bump in the middle, then placed an array of vertical silicon posts, each 50 (billionths of a meter) in diameter, in front of it. Because the posts are much smaller than the of the light, the light behaves as if it were passing through a solid whose density varies with the density of the posts. As light passes between regions of high and low density it is refracted, or bent, in the same way light is refracted as it passes from air to glass. By designing smooth transitions of the density of posts, the researchers could control the path of the light to compensate for the distortion caused by the bump.

As a result, an observer looking at light reflected from the mirror sees a flat mirror, with no sign of the bump. The device is expected to work over a range of wavelengths from infrared into visible red light, the researchers said

Of course it's still a long way to cloaking tanks on a battlefield. For starters, the thing being hidden has to hide behind a mirror, and the presence of a mirror would be a giveaway. A practical also would have to adjust in real time to changing configurations of the object behind it.

A variation of the method might be used to bend light around an object, the researchers suggested, and a light-bending device could be made much larger by using technology that stamps or molds nanoscale patterns onto a surface.

Such refraction control might also be used in reverse, they added, to concentrate light in a small area to efficiently collect solar energy.

"At the core is the fact that we're manipulating , telling it where to go and how to behave," said Carl Poitras, a research associate on the Cornell team.

The device was manufactured at the Cornell Nanoscale Facility, which is supported by the National Science Foundation.

Provided by Cornell University (news : web)

Explore further: The first direct-diode laser bright enough to cut and weld metal

add to favorites email to friend print save as pdf

Related Stories

Next generation cloaking device demonstrated

Jan 15, 2009

A device that can bestow invisibility to an object by "cloaking" it from visual light is closer to reality. After being the first to demonstrate the feasibility of such a device by constructing a prototype ...

A Broadband Light Amplifier on a Photonic Chip

Jul 06, 2006

Cornell University researchers have created a broadband light amplifier on a silicon chip, a major breakthrough in the quest to create photonic microchips. In such microchips, beams of light traveling through ...

A New Reflection in the Mirror

Jan 10, 2007

A research group has devised a new type of mirror that reverses the magnetic field of a light wave upon reflection, rather than its electric field, as regular mirrors do. Seems like a minor difference? It's ...

Silicon photonic crystals key to optical cloaking

Jun 25, 2008

In computer simulations, the researchers have demonstrated an approximate cloaking effect created by concentric rings of silicon photonic crystals. The mathematical proof brings scientists a step closer to a practical solution ...

Recommended for you

'Comb on a chip' powers new atomic clock design

Jul 22, 2014

Researchers from the National Institute of Standards and Technology (NIST) and California Institute of Technology (Caltech) have demonstrated a new design for an atomic clock that is based on a chip-scale ...

Creating optical cables out of thin air

Jul 22, 2014

Imagine being able to instantaneously run an optical cable or fiber to any point on earth, or even into space. That's what Howard Milchberg, professor of physics and electrical and computer engineering at ...

New material puts a twist in light

Jul 18, 2014

Scientists at The Australian National University (ANU) have uncovered the secret to twisting light at will. It is the latest step in the development of photonics, the faster, more compact and less carbon-hungry ...

User comments : 6

Adjust slider to filter visible comments by rank

Display comments: newest first

holoman
5 / 5 (3) May 13, 2009
Manipulating light at the molecular level will
be the future of many applications.

Whom ever comes up with a method to program the geometry structure of nano-molecules with light, electrostatics, and electromagnetics will
have the holy grail of materials science.
QubitTamer
1 / 5 (6) May 13, 2009
But can they make a fully functional female android and i do mean FULLY functional...
latersville
1 / 5 (6) May 14, 2009
But can they make a fully functional female android and i do mean FULLY functional...


They already walk among us! The are called women, with there own lives, families, goals, and dreams. They already posess a sense of self and want to make the best possible life for themselves and theirs. Your description of a lifeless, no willed, machine to serve as your perverted, limitles sexual plaything is nothing short of sociopathic.
Wanting a relationship with a lifeless, sex machine is truly disturbing.
Egnite
3.3 / 5 (4) May 14, 2009
I dunno, for many ppl it would just be a replacement for thier hand.

Your description of a lifeless, no willed, machine to serve as your perverted, limitles sexual plaything is nothing short of sociopathic.


Does the same go for all the females out thier with vibrators then? I think your speaking crap without even thinking about what your saying. You interpret "FULLY functional" as "a lifeless, no willed, machine to serve as your perverted, limitles sexual plaything", what if he was only meaning for it to have reproductive organs so he could start a family or even have "there own lives, families, goals, and dreams" to find a connection with?

Ofc, QubitTamer may well be the pervert you assume he is, in that case please accept my appologies lol.
laserdaveb
3 / 5 (2) May 14, 2009
apparently qubits are the only thing he can tame:D
QT..you need to get out more!
ok..back to the article...didn't we see a similar story recently? so far we can only hide tiny things..oh..i meant to get back to the story...
RayCherry
not rated yet Jul 29, 2009
Can anybody else 'see' the link between the articles on Invisibility Cloaks and those about Dark Matter?