Thermoelectric detection of propagating plasmons in graphene

TL;DR

This paper demonstrates an all-graphene mid-infrared plasmon detector that uses thermoelectric effects to detect propagating plasmons, enabling electrical detection without additional materials.

Contribution

It introduces a novel all-graphene device that detects propagating plasmons via thermoelectric conversion, eliminating the need for external optoelectronic materials.

Findings

Successful detection of propagating plasmons in graphene.

Real-space photocurrent maps reveal plasmon behavior and decay.

Device tunability via local gates enhances control over plasmonic and thermoelectric properties.

Abstract

Controlling, detecting and generating propagating plasmons by all-electrical means is at the heart of on-chip nano-optical processing. Graphene carries long-lived plasmons that are extremely confined and controllable by electrostatic fields, however electrical detection of propagating plasmons in graphene has not yet been realized. Here, we present an all-graphene mid-infrared plasmon detector, where a single graphene sheet serves simultaneously as the plasmonic medium and detector. Rather than achieving detection via added optoelectronic materials, as is typically done in other plasmonic systems, our device converts the natural decay product of the plasmon---electronic heat---directly into a voltage through the thermoelectric effect. We employ two local gates to fully tune the thermoelectric and plasmonic behaviour of the graphene. High-resolution real-space photocurrent maps are used to investigate the plasmon propagation and interference, decay, thermal diffusion, and thermoelectric generation.