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Engineers envision 2-dimensional graphene metamaterials and 1-atom-thick optical devices

June 10, 2011
Graphene Waveguide

A graphene waveguide and splitter (credit: University of Pennsylvania)

Engineers at the University of Pennsylvania have proposed the possibility of one-atom-thick, two-dimensional metamaterials by controlling the conductivity of sheets of graphene.

The engineers manipulated electromagnetic (EM) acoustic waves in the infrared spectrum. Applying direct voltage to a sheet of graphene by way of ground plate running parallel to a sheet of graphene, the engineers were able to change the conductivity of the graphene by varying the voltage or the distance between the ground plate and the graphene sheet.

They demonstrated with computer models that a sheet of graphene (a single layer of carbon atoms) can have two areas that have different conductivities: one that can support a wave, and one that cannot. The boundary between the two areas acts as a wall, capable of reflecting a guided EM wave on the graphene much like one would in a three dimensional space.

The also demonstrated a model that  involves three regions: one that can support a wave surrounded by two that cannot. This produces a “waveguide” that functions like a one-atom-thick fiber optic cable to carry signals. A third model builds on the waveguide, adding another non-supporting region to split the waveguide into two.

The engineers envision applications that include lensing and the ability to do “flatland” Fourier transforms, a fundamental aspect of signal processing.

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