Second-harmonic optical circular dichroism of plasmonic chiral helicoid-III nanoparticles

TL;DR

This paper investigates the strong chiroptical responses of plasmonic chiral helicoid-III nanoparticles in both linear and nonlinear optical regimes, highlighting enhanced chirality effects in the nonlinear regime through calculated g-factors.

Contribution

It provides the first quantification of linear and nonlinear optical chiroptical responses of helicoid-III nanoparticles using g-factors, demonstrating enhanced chirality in the nonlinear regime.

Findings

Linear optical g-factors: -0.12 and -0.43

Nonlinear optical g-factors: -1.45 and -1.63

Chirality is strongly enhanced in the nonlinear regime

Abstract

While plasmonic particles can provide optical resonances in a wide spectral range from the lower visible up to the near-infrared, often symmetry effects are utilized to obtain particular optical responses. By breaking certain spatial symmetries, chiral structures arise and provide robust chiroptical responses to these plasmonic resonances. Here, we observe strong chiroptical responses in the linear and nonlinear optical regime for chiral L-handed helicoid III nanoparticles and quantify them by means of an asymmetric factor, the so-called g-factor. We calculate the linear-optical g-factors for two distinct chiroptical resonances to -0.12 and -0.43 and the nonlinear optical g-factors to -1.45 and -1.63. The results demonstrate that the chirality of the helicoid-III nanoparticles is strongly enhanced in the nonlinear regime.