Optimizing strong light-matter coupling of plasmonic lattices and monolayer semiconductors

TL;DR

This paper presents a novel fabrication method for embedding gold nanodisk arrays into van der Waals heterostructures, enhancing the quality of exciton-polariton lattices for advanced photonic applications.

Contribution

It introduces a new fabrication technique that reduces interfacial irregularities, enabling high-quality, large-area polariton lattices with improved light-matter coupling.

Findings

Strain and surface contamination reduce exciton quality and light-matter interaction.

The new fabrication method improves homogeneity and reduces irregularities in polariton lattices.

Enhanced light-matter coupling enables potential applications in polarization control and topological polaritonics.

Abstract

Exciton-polaritons provide a versatile platform for the study of a wide range of phenomena, including polariton lasers, topological polaritons, and bosonic condensation. Transition metal dichalcogenide monolayers host excitons with large oscillator strength and binding energies constituting a robust matter constituent that forms polaritons from cryogenic to room temperature when embedded in optical microcavities. Plasmonic nanoparticles arranged in lattice geometries offer strong field-confinement and high quality factors. However, the high sensitivity of monolayer excitons to strain and dielectric disorder necessitates encapsulation in atomically flat hBN to ensure a high optical quality, rendering plasmonics more challenging. Here, we employ our recently developed fabrication method for embedding gold nanodisk arrays into van der Waals heterostructures and compare two samples with opposite layer order. We observe that strain and etching-induced surface contamination can reduce the exciton quality and thus the light-matter interaction strength significantly. Our fabrication approach reduces interfacial irregularities and enables homogeneous large-area polariton lattices for a wide range of applications, such as polarization-control or topological polaritonics.