Creation of a Photopolymerized Double Spiral Structure by Interference of Plasmonic Scattering and Circularly Polarized Light

Chiro-optical effects of materials enable many intriguing optical phenomena in the subwavelength regime and are expanding their application in broad areas, such as nano/microfabrication, biosensing, and quantum information. To take advantage of the chiro-optical effect, precise control of chiral structures on the nano- and micrometer scales is crucial. Recently, the possibility of producing strong chiro-optical effects using achiral plasmonic nanostructures has been intensively studied. The interaction of achiral nanostructures with circularly polarized light can break the mirror symmetry and enable the circular-polarization-selective distribution of local electromagnetic fields. In this study, we present a method to create a novel double spiral structure by using achiral plasmonic nanoparticles and circularly polarized light. We focus on the chiral electromagnetic field scattered from the nanoparticle over several micrometer scales, which is sometimes neglected due to the relatively weak intensity of the scattering field. The interference between the circularly polarized incident field and the plasmonic scattering field produced a double spiral pattern of the electromagnetic fields, which was replicated via the photopolymerization reaction and resulted in chiral surface relief patterns on the surface of the polymer layer. We believe that our approach can support the development of novel photonic devices and chiral nanomaterials.