# Nonlinear atom-plasmon interactions enabled by nanostructured graphene

## TL;DR

This paper proposes using nonlinear optical responses of nanostructured graphene to enable resonant coupling with quantum emitters in the near-infrared, overcoming frequency limitations of graphene plasmons.

## Contribution

It introduces a novel scheme utilizing nonlinear near-fields from nanostructured graphene to coherently control quantum states in atomic systems.

## Key findings

- Nonlinear near-fields from graphene nanodisks can excite quantum states.
- Third harmonic of plasmon resonance can be tuned to atomic transitions.
- The scheme avoids strong spontaneous emission enhancement.

## Abstract

Electrically tunable graphene plasmons are anticipated to enable strong light-matter interactions with resonant quantum emitters. However, plasmon resonances in graphene are typically limited to infrared frequencies, below those of optical excitations in robust quantum light sources and many biologically interesting molecules. Here we propose to utilize near fields generated by the plasmon-assisted nonlinear optical response of nanostructured graphene to resonantly couple with proximal quantum emitters operating in the near-infrared. We show that the nonlinear near-field produced by a graphene nanodisk can strongly excite and coherently control quantum states in two- and three-level atomic systems when the third harmonic of its plasmon resonance is tuned to a particular electronic transition. In the present scheme, emitter and plasmon resonances are nondegenerate, circumventing strong enhancement of spontaneous emission. We envision potential applications for the proposed nonlinear plasmonic coupling scheme in sensing and temporal quantum control.