# Merging van der Waals Materials and Optical Metasurfaces for Cavity Quantum Electrodynamics

## TL;DR

This paper explores combining van der Waals materials with optical metasurfaces to enable efficient light-matter interactions for nanoscale devices.

## Contribution

The novel integration of van der Waals materials with qBIC metasurfaces enables self-contained cavity quantum electrodynamics platforms.

## Key findings

- Van der Waals metasurfaces support high-Q resonances and efficient light-matter coupling.
- Self-hybridized cavity-emitter systems enable on-chip integration and nanoscale polaritonic devices.
- vdW materials bridge condensed matter physics and nanophotonics through twist-angle and heterostructure properties.

## Abstract

Flat optical metasurfaces are transforming photonics research by enabling new ways to control light in ultrathin, versatile photonic devices. The rise of quasi‐bound states in the continuum (qBIC) metasurfaces has enabled tailored high‐quality (Q) factor resonances in subwavelength nanostructured thin films, analogous to traditional optical cavities. In this perspective, we explore the emergence of cavity quantum electrodynamics (QED) in optical qBIC metasurfaces, specifically those constructed from van der Waals (vdW) layered materials. Because of their remarkable properties, vdW metasurfaces can support intrinsic optical resonances within the same active material hosting luminescent species, such as excitons or defects, leading to optimal light–matter coupling. This approach of self‐hybridizing the cavity‐emitter system into a single platform effectively overcomes limitations in on‐chip integration of conventional cavities. Combining vdW materials with optically engineered qBIC metasurfaces opens exciting possibilities for exploring nanoscale light–matter interactions. Moreover, the distinctive features of vdW materials, from vertical heterostructures to twist‐angle‐dependent properties, offer a unique platform bridging the condensed matter physics of 2D materials and engineered nanophotonics. We propose that harnessing strong light–matter coupling in vdW‐integrated qBIC metasurfaces will pave the way for next‐generation nanoscale polaritonic devices.

Flat optical metasurfaces supporting quasi‐bound states in the continuum (qBIC) enable cavity‐like, high‐Q resonances in ultrathin nanostructures. This perspective explores the emergence of cavity quantum electrodynamics in qBIC metasurfaces, specifically those made from ultrathin van der Waals nanostructures, where cavities and emitters are seamlessly integrated, enabling efficient light–matter coupling and opening new pathways toward compact, integrated nanoscale polaritonic devices.