Fabrication and Characterization of a Plasmonic Ellipsoidal Nanohole Array With Chiral Response

This study presents a novel approach to fabricate plasmonic nanohole arrays with intrinsic chiral behavior using displacement Talbot lithography, demonstrating a significant dichroic signal of 20%–30% and highlighting its potential for the scalable fabrication of chiral plasmonic platforms. We experimentally confirm that a strong chiroptical effect is achieved by introducing ellipsoidal nanoholes with their principal axes rotated by 18° relative to the principal axes of a square array, a strong circular dichroism response is achieved, which contrasts with the achiral response of circular nanohole arrays. Both experimental and numerical results confirm that the rotation of the ellipsoidal nanohole principal axes with respect to array symmetry lines breaks mirror symmetry, thus enabling circular dichroism even at normal incidence. This approach offers promising applications in chiral sensing and biomolecule optical detection.