Circular polarization selective metamaterial absorber in terahertz frequency range

In this article, we propose a chiral metamaterial absorber based on four rotated twisted closed ring resonators operative in terahertz frequency range. The resonant features are analyzed by electric field amplitude distributions, and surface currents flow generated by the interaction of circularly polarized waves with the chiral structure. The highest field amplitudes at the fundamental resonance are obtained at the gap region of the resonator. Therefore, the efficiency of the proposed absorber is determined through response of absorption spectrum around this resonance with variation of geometrical parameters of the structure. Significant increase of absorption of the left circularly polarized light is obtained with variation of the period size of structure. Consequently, huge circular dichroism, and near-unity polarization selective absorption have been provided. This makes the proposed chiral structure a good candidate for designing circular polarization selective absorber.