# Electronically Tunable Perfect Absorption in Graphene

## TL;DR

This paper demonstrates electronically tunable perfect light absorption in graphene nanostructures, achieving near-unity absorption efficiency by overcoming plasmon-photon mismatch through innovative nanophotonic design.

## Contribution

The authors develop nanophotonic structures that enable high-efficiency, tunable perfect absorption in graphene, surpassing previous limitations of low absorption efficiency.

## Key findings

- 96.9% absorption at 1389 cm$^{-1}$
- 95.9% on/off modulation efficiency
- Design based on critical coupling model

## 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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Source: https://tomesphere.com/paper/1703.03579