Resonant Terahertz Detection Using Graphene Plasmons

TL;DR

This paper demonstrates a graphene-based terahertz detector that uses plasmon resonances to efficiently detect radiation, tune modes, and probe collective excitations, advancing terahertz photonics.

Contribution

It introduces a novel graphene plasmonic detector that combines resonant detection with tunable plasmon modes and enables probing of collective excitations in bilayer graphene.

Findings

Achieved resonant terahertz detection using graphene transistors.

Demonstrated tunability of plasmon modes via gate voltage.

Measured plasmon wavelength and lifetime in bilayer graphene.

Abstract

Plasmons, collective oscillations of electron systems, can efficiently couple light and electric current, and thus can be used to create sub-wavelength photodetectors, radiation mixers, and on-chip spectrometers. Despite considerable effort, it has proven challenging to implement plasmonic devices operating at terahertz frequencies. The material capable to meet this challenge is graphene as it supports long-lived electrically-tunable plasmons. Here we demonstrate plasmon-assisted resonant detection of terahertz radiation by antenna-coupled graphene transistors that act as both plasmonic Fabry-Perot cavities and rectifying elements. By varying the plasmon velocity using gate voltage, we tune our detectors between multiple resonant modes and exploit this functionality to measure plasmon wavelength and lifetime in bilayer graphene as well as to probe collective modes in its moir\'e minibands. Our devices offer a convenient tool for further plasmonic research that is often exceedingly difficult under non-ambient conditions (e.g. cryogenic temperatures and strong magnetic fields) and promise a viable route for various photonic applications.