The Enhanced Optical Chirality Induced by Surface Plasmons in Achiral Magnetoplasmonic Nanostructures

We show theoretically that the enhanced optical chirality in the achiral magnetoplasmonic nanostructures including dual-metallic grating (DMG) structure and single-metallic grating (SMG) structure under linearly polarized light can be achieved. The simulated results, based on the extended finite difference time domain (EFDTD) method, show that the designed structures possess the enhanced optical chirality in the visible and near-infrared wavelengths. More importantly, although the magnetoplasmonic nanostructure with DMG structure possesses an easy fabrication process, its performance of optical chirality is superior to that of the SMG structure. The physical origin of the enhanced optical chirality is deeply researched in detail. We also show that the optical chirality can be adjusted by the external magnetic field, which denotes that the magnetoplasmonic nanostructures will be used to develop a new chiro-optical device.

Automated summary

We theoretically demonstrate that enhanced optical chirality can be achieved in achiral magnetoplasmonic nanostructures, including dual-metallic grating (DMG) structure and single-metallic grating (SMG) structure, under linearly polarized light. Simulated results show that the designed structures exhibit enhanced optical chirality in the visible and near-infrared wavelengths. Furthermore, the DMG structure outperforms the SMG structure in terms of optical chirality, despite the former's easier fabrication process. The physical origin of the enhanced optical chirality is investigated in detail, and the potential for adjusting optical chirality using an external magnetic field suggests the potential development of new chiro-optical devices using magnetoplasmonic nanostructures.