Mechanisms of chiral plasmonics -- scattering, absorption and photoluminescence

TL;DR

This paper develops a model to understand the optical chiral mechanisms in strongly coupled metal nanoparticles, revealing that chirality arises from symmetry, coupling strength, and superposition effects, advancing the field of chiral plasmonics.

Contribution

It introduces a harmonic oscillator interaction model to explain the origins of chirality in plasmonic nanoparticle systems, highlighting new factors influencing optical properties.

Findings

Chirality depends on nanoparticle orientation and eigen parameters.

Symmetry, coupling strength, and superposition contribute to optical chirality.

The model explains scattering, absorption, and photoluminescence chirality mechanisms.

Abstract

Chirality is a concept that one object is not superimposable on its mirror image by translation and rotation. In particular, chiral plasmonics have been widely investigated due to their excellent optical chiral properties, and have led to numerous applications such as optical polarizing element etc. In this study, we develop a model based on the concept of the interaction between harmonic oscillators to investigate and explain the optical chiral mechanisms of strongly coupled metal nanoparticles (MNPs). The chirality of the scattering, absorption, and photoluminescence spectra are carefully discussed in detail. The results show that the chirality of the system originates not only from the orientations of the MNPs, but also from the different eigen parameters between them. Specifically, the derived three factors contribute to the chirality: the symmetry, the coupling strength, and the coherent superposition of the emitted electric field. This work provides a deeper understanding on the chiral plasmonics and may guide relevant applications in theory.