Self-hybridized vibrational-Mie polaritons in water droplets

TL;DR

This paper investigates the self-hybridization of vibrational and Mie optical modes in water droplets, revealing that polaritonic states are common in natural water aerosols and occur at ultrastrong coupling regimes.

Contribution

It demonstrates the existence of vibrational-Mie polaritons in water droplets and highlights their ubiquity in atmospheric phenomena, expanding understanding of natural polaritonic systems.

Findings

Polaritonic states occur in water droplets larger than 2.7 μm.

Self-hybridization is observed at the onset of ultrastrong coupling.

Polaritonic phenomena are present in natural atmospheric water droplets.

Abstract

We study the self-hybridization between Mie modes supported by water droplets with stretching and bending vibrations in water molecules. Droplets with radii $>2.7~\mu m$ are found to be polaritonic on the onset of the ultrastrong light-matter coupling regime. Similarly, the effect is observed in larger deuterated water droplets at lower frequencies. Our results indicate that polaritonic states are ubiquitous in nature and occur in water droplets in mists, fogs, and clouds. This finding may have implications not only for polaritonic physics but also for aerosol and atmospheric sciences.