Multispectral Molecular Chiral Barcoding

More than half of pharmaceutical drugs in use are chiral, necessitating accurate techniques for their characterization. Enantiomers, molecules with mirrored symmetry, often exhibit similar physical traits but possess distinct chemical and biological implications. This study harnesses the strong light-matter interaction induced by "superchiral" light to perform Surface-Enhanced Infrared Absorption (SEIRA) induced vibrational circular dichroism measurements in the mid-infrared spectral region. Utilizing a nanopatterned pixelated array of achiral plasmonic nanostructures, the system allows unique identification of enantiomers and biomolecules. Tunability of plasmon resonance facilitates spectral variation of the optical chirality over a wide infrared range, enabling development of a unique chiral "barcoding" scheme to distinguish chiral molecules based on their infrared fingerprint. This simple, yet robust sensor presents a low-cost solution for chiral mapping of drugs and biomolecules.