Polarization-controlled multifunctional polarization conversion in bilayer chiral metamaterials

Abstract In this paper, a chiral metamaterial (MM) structure composed of bilayer twisted split-ring resonator (SRR) arrays is proposed and demonstrated to realize polarization-controlled, dual-directional, and multifunctional polarization conversion for terahertz (THz) waves. Simulated results show that the converter can selectively achieve linear-to-linear, or linear to left-handed circular, or linear to right-handed circular’s polarization conversion according to the polarization state and propagating direction of the incident THz wave. Stokes parameters, ellipticity, and polarized rotation angle are introduced to determine the polarization states of the output waves. The circular polarization transmission coefficients and surface current distributions at the resonance frequency points are simulated to explain and demonstrate the physical origin of polarization conversion. The proposed multifunctional converter can find potential applications in THz sensing, imaging and communication areas.