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 in 2006, a team of Duke University engineers has produced a new type of cloaking device, which is significantly more sophisticated at cloaking in a broad range of frequencies.

The latest advance was made possible by the development of a new series of complex mathematical commands, known as algorithms, to guide the design and fabrication of exotic composite materials known as metamaterials. These materials can be engineered to have properties not easily found in natural materials, and can be used to form a variety of “cloaking” structures. These structures can guide electromagnetic waves around an object, only to have them emerge on the other side as if they had passed through an empty volume of space.

The results of the latest Duke experiments were published Jan. 16 in the journal Science. First authors of the paper were Duke’s Ruopeng Liu, who developed the algorithm, and Chunlin Li. David R. Smith, William Bevan Professor of electrical and computer engineering at Duke, is the senior member of the research team.

Once the algorithm was developed, the latest cloaking device was completed from conception to fabrication in nine days, compared to the four months required to create the original, and more rudimentary, device. This powerful new algorithm will make it possible to custom-design unique metamaterials with specific cloaking characteristics, the researchers said.

“The difference between the original device and the latest model is like night and day,” Smith said. “The new device can cloak a much wider spectrum of waves — nearly limitless — and will scale far more easily to infrared and visible light. The approach we used should help us expand and improve our abilities to cloak different types of waves.”

Cloaking devices bend electromagnetic waves, such as light, in such a way that it appears as if the cloaked object is not there. In the latest laboratory experiments, a beam of microwaves aimed through the cloaking device at a “bump” on a flat mirror surface bounced off the surface at the same angle as if the bump were not present. Additionally, the device prevented the formation of scattered beams that would normally be expected from such a perturbation.

The underlying cloaking phenomenon is similar to the mirages seen ahead at a distance on a road on a hot day.

“You see what looks like water hovering over the road, but it is in reality a reflection from the sky,” Smith explained. “In that example, the mirage you see is cloaking the road below. In effect, we are creating an engineered mirage with this latest cloak design.”

Read more . . .

Related articles

• One step closer to a real cloaking device
• Five uses for an invisibility material (other than dumb Harry Potter references)
• Invisibility cloak closer than ever to reality
• Cloaking device puts the kibosh on cellphone interference
• Duke’s Former Dungeon Masters Invent Invisibility Cloak
• Harry Potter invisibility cloak a step closer to reality

Related posts:

1. New Cloaking Method Could Shield Submarines From Sonar, Planes From Radar, Buildings From Earthquakes
2. Nano-magnets in metamaterials pave the way to invisibility cloaks
3. Experts unveil ‘cloak of silence’
4. Invisibility Cloak And Ultra-powerful Microscopes: New Research Field Promises Radical Advances In Optical Technologies
5. ‘Invisibility Cloak’ Successfully Hides Objects Placed Under It

Tags: algorithms, cloaking device, cloaking devices, david r smith, duke university, electromagnetic waves, Innovation, metamaterials, visible light

This entry was posted on Sunday, January 18th, 2009 at 10:44 am and is filed under Innovation, Science Digest / Science Daily. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.