Chiral cavities made from lattices of highly electromagnetically-chiral scatterers

TL;DR

This paper introduces a novel chiral infrared optical cavity constructed from lattices of silver helices, achieving high helicity selectivity and dissymmetry, which could enhance enantio-selective molecular applications.

Contribution

It presents the design of a highly chiral optical cavity using planar lattices of silver helices, maximizing electromagnetic chirality and dissymmetry for the first time.

Findings

Achieves 95% dissymmetry inside the cavity at the target frequency.

Combines helicity selectivity with helicity-preserving reflectivity.

Potential for improved enantio-selective optical applications.

Abstract

The infamous weakness of molecular chiroptical responses challenges the all-optical realization of crucial applications such as enantio-selective sorting of chiral molecules, or biasing chiral chemical reactions. Chiral optical cavities are a natural choice for confronting this challenge. Ideally, the dissymmetry between the two helicities inside such cavities is maximized. In here, we propose a chiral infrared optical cavity formed by planar mirrors made of diffracting lattices of silver helices with almost maximum electromagnetic chirality. It combines the strong helicity selectivity of the helices with the helicity-preserving reflectivity that planar systems show at large incidence angles. For the manifold of cavity modes which have a component with zero in-plane momentum, we demonstrate an unprecedented dissymmetry of 95 % inside the cavity at the target frequency, making it a compelling candidate for enantio-selective applications.