Scientists are regularly characterized as having leftist leanings, but a group of students and faculty working with the U.S. Department of Energy’s Ames Laboratory is working to convert light to the right.

Costas Soukoulis, distinguished professor of physics and astronomy and Ames Laboratory researcher and Gary Tuttle, associate professor with the microelectronics research center, are leading one of a handful of collaborations around the world researching synthetic materials known as metamaterials that have the seemingly miraculous quality of convincing light to bend over backward.

“What we are doing is essentially rewriting electrodynamics,” Soukoulis said.

Light entering normal translucent material, such as glass, bends to the left of the normal, an imaginary line perpendicular to the surface of the material. Light entering a metamaterial has the opposite behavior, bending to the right of the normal. In the lab, light can bend backwards because metamaterials are synthetically created to have a negative index of refraction.

Metamaterials are also referred to as “left-handed” materials because light traveling through metamaterials follows a “left-hand rule.” Electromagnetic waves usually travel 90 degrees to the right of the axis of their electric and magnetic fields. This convention is known as the “right-hand rule” and is often visualized by pointing the thumb and the index and middle finger of the right hand perpendicular to each other to determine the direction a wave will travel. Metamaterials behave in the opposite fashion, waves travel the opposite way they do through a normal medium.

“These materials have completely different properties than the constituents,” Soukoulis said.

In an over-exaggerated illustration of the phenomenon, a spoon immersed in a glass of water would appear to make an abrupt 90 degree bend to the right below the waterline. Tuttle, who leads the experimental wing of the project, said such images of light breaking with its usual conservatism to make an abrupt right turn, make a significant impression.

“To someone who is familiar with science it is a pretty clear indication that something odd is happening,” Tuttle said.

A material’s index of refraction is determined by its values for the variables upsilon and mew. In nature these values never negative at the same time. Metameterials use more than one material to create artificial atoms that have negative values for upsilon and mew at the same time.

At the Ames Lab, this effect is achieved by layering specially designed tile patterns of metal on both sides of a dielectric plate. Because the tiles are smaller than the wavelength of light they are designed to refract, light reacts to the tiles as individual atoms. Precise shaping of the tiles produces metamaterials with different properties, including variants that absorb all incoming light at their wavelengths.

Currently the effect can only be achieved at wavelengths significantly longer than visible light such as infrared radiation. Materials produced at Ames Lab are able to refract incoming microwaves with a wavelength of around five microns. Smaller tiles are required for metamaterials to work at visible light’s smaller wavelengths, however current manufacturing techniques are not able to produce precisely formed tiles at this scale.

Researchers and others have already imagined applications for negative refraction, ranging from a flat “super lens” to visual cloaking that would render an object invisible by channeling light around the object. Although expectations are already high, Tuttle said it may be too early to decide what role metamaterial-based technologies will play in the future.

“If there is a good application out there somebody will find it,” Tuttle said. “You do the science and the technology will take care of itself.”

Soukoulis said he believes large wavelength applications, such as using metamaterials to create efficient antennae, could be on the market within five to 10 years with applications in the visual spectrum taking at least an additional five years. He said certain applications will come more easily than others.

“Cloaking is very far-fetched for my tastes,” Soukoulis said.

A first step to advanced applications will be developing the manufacturing ability to test advanced designs already being developed by theorists.

“Theory is nice, but if you actually want new technology you have to build something,” Tuttle said.

Soukoulis said researchers’ next challenge is to make 3-D materials. Current materials only refract waves coming from a specific orientation. Overcoming this limitation is necessary to realize either the super lens or cloaking applications.

“One of the problems to hide things in gigahertz is that you have to make 3-D isotropic materials,” Soukoulis said. “We are very far from that.”