Towards chiral acoustoplasmonics

TL;DR

This paper introduces a simple chiral nanostructure that controls electromagnetic properties based on light helicity, enabling enhanced phonon excitation and detection, advancing acoustoplasmonic device design.

Contribution

It presents a novel crossed bar nanostructure that exhibits strong chiral optical responses and demonstrates potential for improved phonon manipulation in acoustoplasmonic applications.

Findings

Achieved 200% difference in absorption and scattering based on light helicity.

Proposed a coherent phonon generation experiment using circularly polarized light.

Demonstrated potential for efficient chiral acoustoplasmonic transducers.

Abstract

The possibility of creating and manipulating nanostructured materials encouraged the exploration of new strategies to control electromagnetic properties. Among the most intriguing nanostructures are those that respond differently to helical polarization, i.e., exhibit chirality. Here, we present a simple structure based on crossed elongated bars where light-handedness defines the dominating cross-section absorption or scattering, with a 200% difference from its counterpart (scattering or absorption). The proposed chiral system opens the way to enhanced coherent phonon excitation and detection. We theoretically propose a simple coherent phonon generation (time-resolved Brillouin scattering) experiment using circularly polarized light. In the reported structures, the generation of acoustic phonons is optimized by maximizing the absorption, while the detection is enhanced at the same wavelength -- and different helicity -- by engineering the scattering properties. The presented results constitute one of the first steps towards harvesting chirality effects in the design and optimization of efficient and versatile acoustoplasmonic transducers.