Atomically imprinted graphene plasmonic cavities

TL;DR

This paper introduces a method to atomically imprint low-loss graphene plasmonic cavities with nanoscale precision using oxidation-activated charge transfer, enabling advanced quantum photonic architectures.

Contribution

The study presents a novel OCT technique to create high-quality, nanoscale, doped graphene plasmonic cavities with precise control over carrier density and doping profiles.

Findings

Achieved low-loss plasmon polaritons at WOx/graphene interface.

Controlled carrier density with WSe2 spacers for high-quality plasmons.

Imprinted nanoscale plasmonic whispering-gallery resonators.

Abstract

Plasmon polaritons in van der Waals (vdW) materials hold promise for next-generation photonics. The ability to deterministically imprint spatial patterns of high carrier density in cavities and circuitry with nanoscale features underlies future progress in nonlinear nanophotonics and strong light-matter interactions. Here, we demonstrate a general strategy to atomically imprint low-loss graphene plasmonic structures using oxidation-activated charge transfer (OCT). We cover graphene with a monolayer of WSe$_2$, which is subsequently oxidized into high work-function WOx to activate charge transfer. Nano-infrared imaging reveals low-loss plasmon polaritons at the WOx/graphene interface. We insert WSe$_2$ spacers to precisely control the OCT-induced carrier density and achieve a near-intrinsic quality factor of plasmons. Finally, we imprint canonical plasmonic cavities exhibiting laterally abrupt doping profiles with single-digit nanoscale precision via programmable OCT. Specifically, we demonstrate technologically appealing but elusive plasmonic whispering-gallery resonators based on free-standing graphene encapsulated in WOx. Our results open avenues for novel quantum photonic architectures incorporating two-dimensional materials.