[14p-K305-1~14] 3.1 Basic optics and frontier of optics

4:15 PM - 4:30 PM JST(7:15 AM - 7:30 AM UTC)

[14p-K305-10] Exploration of Optical Chirality Based on the Orbital Angular Momentum of Light Using a Single Chiral Metallic Nanostructure as a Probe

〇Shun Hashiyada¹, Yoshito Tanaka¹ (1.RIES Hokkaido Univ.)

Keywords:

optical vortex,circularly polarized light,optical chirality

The chirality of a material is identified through asymmetric interactions with chiral materials or fields. Circularly polarized light (spin angular momentum s=±1) is a chiral electromagnetic field, and its interaction with chiral materials gives rise to circular dichroism (CD). CD primarily originates from electric dipole and magnetic dipole modes and depends on optical chirality based on spin angular momentum (spin OC). This study analyzes the interaction between optical vortices carrying orbital angular momentum (l) and chiral twisted gold nanorod dimers (TND). In experiments using circularly polarized optical vortex beams (s=±1,l=±1), TND exhibited helical dichroism (HD) with a wavelength-dependent signal at the center of the vortex beam, which cannot be explained by spin OC. These results suggest that HD depends on a new physical parameter of chirality, orbital OC.