The unnatural charm of metamaterials

IOWA STATE (US) — New fabrication techniques are yielding metamaterials—exotic creations that provide optical properties not found in nature.

Sometimes called left-handed materials, metamaterials are able to refract light to the left, or at a negative angle—something natural materials just can’t do.

“This backward-bending characteristic provides scientists the ability to control light similar to the way they use semiconductors to control electricity, which opens a wide range of potential applications,” says Costas Soukoulis, a physicist at Iowa State University.

One possibility is using metamaterials to develop a flat superlens that operates in the visible light spectrum.

“Such a lens would offer superior resolution over conventional technology, capturing details much smaller than one wavelength of light to vastly improve imaging for materials or biomedical applications,” Soukoulis says. “A metamaterial superlens could give researchers the power to see inside a human cell or observe DNA.”

In a recent issue of the journal Science, Soukoulis and physicist Martin Wegener describe the development of optical metamaterials from thin films to 3-D nanostructures. They also describe the challenges of further, practical development of the new materials.

“First, the structures must be tiny and are therefore difficult and expensive to produce,” Soukoulis says. “Optical metamaterials also absorb light, making it difficult to create a metamaterial superlens.”

But Soukoulis and Wegener say there’s hope. Experiments have demonstrated optical metamaterials can operate within the visible light spectrum, 3-D optical metamaterials can be produced and light loss in metamaterials can be reduced.

The ideal optical metamaterial requires all three properties, they note. Wrapping them all into one new metamaterial will take more research and development. And then, researchers will need to find ways to reduce the cost of production.

The introduction of advanced fabrication techniques to metamaterials research “may lead to realization of such designer materials,” they write.

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