Probing Molecular Chirality via Linear Dichroism of Molecule‐Loaded Anisotropic Plasmonic Slots

Abstract

ABSTRACT Conventional chiroptical spectroscopy relies on circularly polarized light (CPL), yet inherent retardance errors in CPL generation compromise signal fidelity and introduce artifacts from crosstalk with linear dichroism and birefringence. Here, we theoretically propose Chiroptical sensing via Linear dichroism of Anisotropic Plasmonic Slots (CLAPS), a CPL‐free chiroptical sensing scheme that employs two linearly polarized light (LPL) beams tilted with respect to the orientation axis of a plasmonic slot array filled with chiral analytes. Molecular optical activity perturbs the surface lattice resonance (SLR) of the array, producing a measurable reflectance difference between the two tilted LPL beams. Using an anisotropic chiral reflection model and numerical simulations, we reveal that the weak cross‐polarized reflection carrying chirality information is modulated by the strong co‐polarized response of the array. CLAPS circumvents the need for high‐purity CPL, offering a practically accessible route to trace‐level chiral molecule detection.