Continuously-tunable light-matter coupling in optical microcavities with 2D semiconductors

TL;DR

This paper proposes a theoretical method to actively and continuously tune light-matter coupling strength in optical microcavities with 2D semiconductors, enabling real-time control of exciton-polariton properties for advanced photonic applications.

Contribution

It introduces a tunable microcavity design that allows real-time adjustment of Rabi splitting and coupling regimes, applicable across various materials including 2D semiconductors, quantum dots, and molecules.

Findings

Simulations show active control of coupling strength via cavity length and angle adjustments.

Proposal for continuous tuning of Rabi splitting in microcavities at room temperature.

Potential applications in polariton chemistry, optical sensing, and topological photonics.

Abstract

A theoretical variation between the two distinct light-matter coupling regimes, namely weak and strong coupling, becomes uniquely feasible in open optical Fabry-P\'erot microcavities with low mode volume, as discussed here. In combination with monolayers of transition-metal dichalcogenides (TMDCs) such as WS2, which exhibits a large exciton oscillator strength and binding energy, the room-temperature observation of hybrid bosonic quasiparticles, referred to as exciton-polaritons and characterized by a Rabi splitting, comes into reach. In this context, our simulations using the transfer-matrix method show how to tailor and alter the coupling strength actively by varying the relative field strength at the excitons' position - exploiting a tunable cavity length, a transparent PMMA spacer layer and angle-dependencies of optical resonances. Continuously tunable coupling for future experiments is hereby proposed, capable of real-time adjustable Rabi splitting as well as switching between the two coupling regimes. Being nearly independent of the chosen material, the suggested structure could also be used in the context of light-matter-coupling experiments with quantum dots, molecules or quantum wells. While the adjustable polariton energy levels could be utilized for polariton-chemistry or optical sensing, cavities that allow working at the exceptional point promise the exploration of topological properties of that point.