Novel Superchiral Light Generation in Achiral Resonant Systems*

In this work we introduce a novel superchiral light generation mechanism based on degenerate achiral systems. The theoretical model employs an electromagnetic rotating dipole to obtain a close form spatial chiral near-field distribution equation. This physical model predicts the solution of single-handed chiral near-field generation in the entire volume of interest with full handedness reversal based solely on the excitation condition. These physical predictions are further observed on a degenerate cavity-coupled achiral plasmonic substrate supporting a fundamental localized surface plasmon (LSP) displaying a dipolar resonance. FDTD simulations demonstrate the predicted superchiral near field generation mechanism with zero far-field circular dichroism signal on the same achiral substrate. Finally, surface enhanced vibrational circular dichroism is demonstrated on two chiral enantiomers on the same substrate showing up to four orders of magnitude enhancement over its volumetric counterpart. These results will promote further research in superchiral near-field generation and surface enhanced chiral light-matter interactions.