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Researchers Discover New Way to Turn Electricity Into Light, ­sing Graphene

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The process of light emission from a sheet of graphene.

Researchers have discovered a current flow in a sheet of graphene can,under certain circumstances, exceed the speed of slowed-down light and produce an intense, focused beam of light.

Credit: MIT News

Researchers at the Massachusetts Institute of Technology (MIT) and elsewhere discovered a sheet of graphene can cause an electric current to surpass the speed of decelerated light and rapidly and efficiently generate an intense, focused beam.

"Graphene has this ability to trap light, in modes we call surface plasmons," says MIT postdoctoral researcher Ido Kaminer. He notes these particles' speed through the material is "a few hundred times slower than light in free space."

A related property of graphene is its ability to induce electrons to pass through it at about 1/300th the speed of light in a vacuum, which is sufficiently close to the plasmons' velocity so significant interactions might transpire between the two particles, if the graphene could be tuned to get the speeds to match.

MIT professor Marin Soljacic says the conversion of electricity to light "is made possible because the electronic speed can approach the light speed in graphene, breaking the 'light barrier.'"

The researchers think tapping this phenomenon, called the Cerenkov effect, could eventually be part of more efficient, more compact, faster, and more tunable alternatives for particular applications. They speculate graphene-based systems could potentially function as critical on-chip components for the production of new, light-based circuits.

Soljacic plans to develop working, proof-of-concept versions of graphene as an on-chip light source.

From MIT News
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