Giant chiral optical response from a twisted-arc metamaterial.

Cui, Yonghao; Kang, Lei; Lan, Shoufeng; Rodrigues, Sean; Cai, Wenshan · Nano Lett · 2014

basic_science · Level V

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Abstract

We demonstrate enormously strong chiral effects from a photonic metamaterial consisting of an array of dual-layer twisted-arcs with a total thickness of ∼ λ/6. Experimental results reveal a circular dichroism of ∼ 0.35 in the absolute value and a maximum polarization rotation of ∼ 305°/λ in a near-infrared wavelength region. A transmission of greater than 50% is achieved at the frequency where the polarization rotation peaks. Retrieved parameters from measured quantities further indicate an actual optical activity of 76° per λ and a difference of 0.42 in the indices of refraction for the two circularly polarized waves of opposite handedness.