The enhanced optical chirality induced by surface plasmons in achiral magnetoplasmonic nanostructures

AbstractWe show theoretically that the enhanced optical chirality in the magnetoplasmonic achiral 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 have enhanced optical chirality in the visible and near-infrared wavelengths. More importantly, although the magnetoplasmonic nanostructure with DMG structure possesses the 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 new chirooptical device.