An inverse-designed nanophotonic interface for excitons in atomically thin materials

TL;DR

This paper presents an inverse-designed nanophotonic platform using hexagonal boron nitride to enhance and interface with atomically thin 2D materials, enabling efficient optical control and detection for quantum and classical applications.

Contribution

It introduces a complete nanophotonic platform combining inverse design, hBN encapsulation, and various photonic components for improved interaction with 2D materials.

Findings

Enhanced exciton-photon coupling via tunable cavities.

Efficient detection of dark excitons with metasurfaces.

Integrated nanophotonic structures improve quantum optics applications.

Abstract

Efficient nanophotonic devices are essential for applications in quantum networking, optical information processing, sensing, and nonlinear optics. Extensive research efforts have focused on integrating two-dimensional (2D) materials into photonic structures, but this integration is often limited by size and material quality. Here, we use hexagonal boron nitride (hBN), a benchmark choice for encapsulating atomically thin materials, as a waveguiding layer while simultaneously improving the optical quality of the embedded films. When combined with photonic inverse design, it becomes a complete nanophotonic platform to interface with optically active 2D materials. Grating couplers and low-loss waveguides provide optical interfacing and routing, tunable cavities provide a large exciton-photon coupling to transition metal dichalcogenides (TMD) monolayers through Purcell enhancement, and metasurfaces enable the efficient detection of TMD dark excitons. This work paves the way for advanced 2D-material nanophotonic structures for classical and quantum nonlinear optics.