# Substrate-Induced Chirality in an Individual Nanostructure

## TL;DR

This paper reports the first experimental observation of substrate-induced chirality in a single nanostructure, revealing how substrate placement can induce chiral optical responses in heterogenous nanoparticle arrangements.

## Contribution

It demonstrates that placing a nanostructure on a substrate can induce chirality and enable chiral optical effects that are otherwise forbidden, advancing understanding of substrate-nanostructure interactions.

## Key findings

- Substrate placement induces chirality in nanostructures.
- Chirality leads to differential extinction, circular dichroism, and optical rotation.
- First experimental evidence of substrate-induced symmetry breaking in nanostructures.

## Abstract

We experimentally investigate the chiral optical response of an individual nanostructure consisting of three equally sized spherical nanoparticles made of different materials and arranged in \ang{90} bent geometry. Placing the nanostructure on a substrate converts its morphology from achiral to chiral. Chirality leads to pronounced differential extinction, i.e., circular dichroism and optical rotation, or equivalently, circular birefringence, which would be strictly forbidden in the absence of a substrate or heterogeneity. This first experimental observation of the substrate-induced break of symmetry in an individual heterogeneous nanostructure sheds new light on chiral light-matter interactions at substrate-nanostructure interfaces.