Strong Interaction between Surface Plasmons and Chiral Molecules

TL;DR

This paper investigates the strong interaction between surface plasmons and chiral molecules, revealing mechanisms like Rabi splitting, enhanced absorption, and transparency, with implications for chiral plasmonic applications.

Contribution

It introduces a spherical core-shell model to analyze spectral phenomena under circularly polarized light, highlighting how chirality influences plasmon-molecule interactions.

Findings

Rabi splitting up to 243 meV observed

Stronger interaction with opposite chirality to CPL

Identification of mechanisms: strong coupling, absorption enhancement, transparency

Abstract

In plasmonic chirality, the phenomenon of circular dichroism for achiral nanoparitcles caused by Coulomb interaction between metal nanoparticles (NPs) and chiral molecules have been studied. At the same time, under the resonance condition, the dye molecules and metal NPs will produce huge Rabi splitting due to strong coupling. If the chiral molecules are at the resonance of the plasmon, what will happen for the strong interaction between the plasmon and molecules with chirality introduced? In this paper, we investigate a spherical core-shell model and analyze its spectral phenomena under the excitation of circularly polarized light (CPL). Based on Coulomb interaction between NPs and chiral molecules, we will show how the various factors affect the strong coupling. We have obtained three mechanisms for the interaction between plasmons and chiral molecules: strong coupling (Rabi splitting up to 243mev), enhanced absorption and induced transparency. The interaction between CPL and chiral molecules with the opposite chirality to CPL is stronger than that of the same chirality, and the line width of the two peaks is closer than that of the same chirality, which shows that for the Rabi splitting with chirality, there are deeper mechanisms for the interaction. This result will be helpful for further research on the interaction between plasmon and molecules with chirality.