No abstract

We report strong circular dichroism and asymmetric transmission of linearly and circularly polarized waves in hybrid bilayer metamaterials. In contrast to previous literatures, the bilayer metamaterials are constructed by two twisted gold complementary asymmetric nanostructures, spatially separated by a dielectric layer. Both the anisotropy and chirality contribute to asymmetric transmission and circular dichroism. The hybrid metamaterial with twisted asymmetrically split rings and apertures simultaneously exhibits strong circular dichroism and linear and circular asymmetric transmission up to 0.4. The proposed scheme can achieve strong dual-band chiroptical effects for both linearly and circularly polarized waves. The polarization conversion efficiencies and resonant frequencies can be engineered via parametric study. The hybrid metamaterial offers a route to realize multifunctional polarization devices and polarization information detections.