Molecular monolayer strong coupling in dielectric soft microcavities

TL;DR

This study demonstrates room-temperature strong coupling between a monolayer of dye molecules and whispering gallery modes in dielectric microspheres, with potential applications in microfluidic systems.

Contribution

It provides experimental evidence of strong coupling with multiple dye layers and compares results with simulations, advancing molecular cavity quantum electrodynamics.

Findings

Rabi splitting increases with more dye layers

Good agreement between experiments and models

Potential for microfluidic integration

Abstract

We report strong coupling of a monolayer of J-aggregated dye molecules to the whispering gallery modes of a dielectric microsphere at room temperature. We systematically studied the evolution of strong coupling as the number of layers of dye molecules was increased, we found the Rabi splitting to rise from 56 meV for a single layer to 94 meV for four layers of dye molecules. We compare our experimental results with 2D numerical simulations and a simple coupled oscillator model, finding good agreement. We anticipate that these results will act as a stepping stone for integrating molecule-cavity strong coupling in a microfluidic environment since microspheres can be easily trapped and manipulated in such an environment, and provide open access cavities.