Metamaterial? Have Scientists Developed an Invisible Cloak?

Researchers are reporting advancements in “metamaterials,” used in such optical technology as ultra-powerful microscopes, computers and possibly an invisibility cloak, according to Purdue University .

The university news service reported that metamaterial research often hits a snag because too much light is “lost” or absorbed by metals such as silver and gold contained in the metamaterials. This makes them impractical for optical devices.

A university research team believes it is making advances after three years of research based at the Birck Nanotechnology Center at Purdue.

“We showed that, in principle, it’s feasible to conquer losses and develop these materials for many applications,” said Vladimir Shalaev, Purdue’s Robert and Anne Burnett Professor of Electrical and Computer Engineering.

The researchers developed a material made of a fishnet-like film containing holes about 100 nanometers in diameter. There are repeating layers of silver and aluminum oxide.

Researchers etched away a portion of the aluminum oxide between silver layers and put a “gain medium” made of a colored dye that can amplify light in its place.

Placing it between the fishnet layers of silver made it work 50 times more efficiently than past attempts where it was placed elsewhere.

The Nanoclast blog on IEEE Spectrum said the Purdue announcement follows another about a nano-enabled coating that made an aircraft invisible to radar.

The blog stated that the Purdue advancements mean applications such as a “planar hyperlens” that makes “optical microscopes 10 times more powerful and able to see objects as small as DNA” are plausible again.

The website io9 said the idea is that light doesn’t refract when it hits the metamaterials. That could help in a number of applications including invisibility.

The research is being funded by the U.S. Army Research Office and the National Science Foundation.

According to Purdue, future attempts may focus on creating a technology that uses an electrical source instead of a light source. The technology would make them more practical for computers and electronics.

http://www.kljb.com/dpps/news/what-is-metamaterial-invisible-cloak-dpgoha-20100812-fc_9133602