Effects of metasurface geometry on magnetic dipole resonances for circular asymmetric transmission in the ultraviolet region

Abstract

Manipulation of circularly polarized light (CPL) in the ultraviolet (UV) region holds significant potential for advancing chiral molecules sensing. Recently, chiral metasurfaces have been applied to control CPL in the UV region. However, the spectral selectivity of the existing UV chiral metasurfaces is still limited. Here, we report rod-shaped and ring-shaped metasurfaces sustaining perpendicularly aligned magnetic dipoles (MDs) and capable of inducing narrowband transmission dips. These MDs can be selectively excited in an eccentric ring-shaped metasurface by left-handed and right-handed circularly polarized lights. By exploiting this phenomenon, the selective asymmetric transmission of CPL with opposite handedness within the UV region is reported. A circular asymmetric transmission with a transmittance dissymmetry factor as high as 1.56 and a narrow full width at half maximum of 1.2 nm is achieved.