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arXiv · 1703.03579

Electronically Tunable Perfect Absorption in Graphene

Seyoon Kim·Min Seok Jang·Victor W. Brar·Kelly W. Mauser·Harry A. Atwater
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Abstract

Graphene nanostructures that support surface plasmons have been utilized to create a variety of dynamically tunable light modulators, motivated by theoretical predictions of the potential for unity absorption in resonantly-excited monolayer graphene sheets. Until now, the generally low efficiencies of tunable resonant graphene absorbers have been limited by the mismatch between free-space photons and graphene plasmons. Here, we develop nanophotonic structures that overcome this mismatch and demonstrate electronically tunable perfect absorption achieved with patterned graphenes covering less than 10% of the surface. Experimental measurements reveal 96.9% absorption in the graphene plasmonic nanostructure at 1,389 cm$^{-1}$, with an on/off modulation efficiency of 95.9% in reflection. An analytic effective surface admittance model elucidates the origin of perfect absorption, which is design for critical coupling between free-space modes and the graphene plasmonic nanostructures.

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Seyoon Kim, Min Seok Jang, Victor W. Brar, Kelly W. Mauser, Harry A. Atwater. 2017-03-10. Electronically Tunable Perfect Absorption in Graphene. https://doi.org/10.1021/acs.nanolett.7b04393

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