Plasmonic superchiral lattice resonances in the mid-infrared

TL;DR

This paper presents the design, fabrication, and characterization of chiral plasmonic slit arrays in the mid-infrared, leveraging lattice resonances to enhance superchiral fields for improved chiral molecule detection.

Contribution

It introduces a novel plasmonic platform with collective lattice resonances that amplify superchiral fields in the mid-infrared, enabling better vibrational circular dichroism measurements.

Findings

Enhanced chiral fields in mid-infrared achieved

Sharp circular dichroism spectral features demonstrated

Potential for improved chiral molecule sensing shown

Abstract

Recent efforts in the field of surface-enhanced spectroscopies have focused on the paradigm of superchirality, entailing the engineering of the local electromagnetic fields to boost the enantiospecific interaction between light and chiral molecules. In this framework, approaches based on both metallic and dielectric nanostructures have been proposed and have also recently been extended to vibrational circular dichroism in the mid-infrared. In this work, we design, fabricate and characterize arrays of chiral plasmonic slits featuring enhanced chiral fields in the mid-infrared. We exploit collective lattice resonances to further enhance the local intensity and to generate sharp features in the circular dichroism spectra of the platform. Such features are ideally suited to test the superchiral coupling with the vibrational resonances of chiral molecules.