2017/03/10 by Seyoon Kim, Min Seok Jang, Victor W. Brar +2 · 1 citation
Physics and Astronomy · #physics.optics
paper · pdf · doi:10.1021/acs.nanolett.7b04393
published as Nano Lett, 18, 971-979 (2018)
arxiv created 2017/03/10 · arxiv updated 2018/02/20
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.