Metamaterial can switch lightwaves like circuits: Duke U

02 Aug 2011

Researchers at Duke University's Pratt School Of Engineering say they’ve developed a material that “allows them to manipulate light in much the same way that electronics manipulate flowing electrons”, which could herald a major advancement in photonic switching for optical networks.

The “material” in question is a “metamaterial” – which is to say, an artificial composite material that “can be engineered to exhibit properties not readily found in nature”. The research group, led by David R. Smith, has been working with similar metamaterials to develop things from advanced optical lenses and wireless charging to invisibility cloaks (no, really).

In this case, the metamaterial device is made of individual pieces of the same fiberglass material used in circuit boards arranged in parallel rows, with each piece etched with copper circles.

I’ll let the Duke press release explain the science:

When light passes through a material, even though it may be reflected, refracted or weakened along the way, it is still the same light coming out. This is known as linearity.

“For highly intense light, however, certain 'nonlinear' materials violate this rule of thumb, converting the incoming energy into a brand new beam of light at twice the original frequency, called the second-harmonic,” said Alec Rose, graduate student in the laboratory of David R. Smith, William Bevan Professor of electrical and computer engineering at Duke’s Pratt School of Engineering. […]

“Normally, this frequency-doubling process occurs over a distance of many wavelengths, and the direction in which the second-harmonic travels is strictly determined by whatever nonlinear material is used,” Rose said. “Using the novel metamaterials at microwave frequencies, we were able to fabricate a nonlinear device capable of 'steering' this second-harmonic. The device simultaneously doubled and reflected incoming waves in the direction we wanted.”

The upshot, says Rose, is that having that level of control over light is unique to nonlinear metamaterials, and “can have important consequences” in all-optical communications.

“To be able to control light in the same manner that electronics control currents will be an important step in transforming telecommunications technologies,” Rose says.

Indeed it would, though it seems this kind of technology is years away from commercial reality. But then I’m not a physicist or an engineer, so those of you with that layer of optics expertise, feel free to post yr thoughts on how big a “breakthrough” this is for the all-optical dream that the telecoms space has been chasing for years.

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