# Nonlinear optical response of a local surface plasmon coupled to a 2D material

## TL;DR

This paper theoretically investigates a coupled system of a metal nanoparticle's surface plasmon and a monolayer transition-metal dichalcogenide, revealing strong nonlinear and quantum optical effects with potential applications in metamaterials and quantum photonics.

## Contribution

It introduces a novel model of a nonlinear oscillator combining surface plasmons and 2D materials, predicting enhanced nonlinearity and quantum features not previously demonstrated.

## Key findings

- Seven orders of magnitude increase in nonlinearity compared to silicon photonic cavities.
- Observation of quantum features such as antibunching and non-Gaussianity.
- Potential for creating nanoscale nonlinear optical metamaterials.

## Abstract

We present a theoretical study of the optical response of a nonlinear oscillator formed by coupling a metal nanoparticle local surface plasmon resonance to excitonic degrees of freedom in a monolayer transition-metal dichalcogenide. We show that the combined system should exhibit strong anharmonicity in its low-lying states, predicting for example a seven order-of-magnitude increase in nonlinearity relative to a silicon photonic crystal cavity. Then, we demonstrate that such system exhibits strong quantum features such as antibunching and non-Gaussianity. Arrays of such nanoscale nonlinear oscillators could be used to realize novel optical metamaterials; alternatively, an individual nanoparticle-monolayer construct could be coupled to an optical resonator to mediate efficient input-output coupling to propagating fields.