Construction of Chiral Metamaterial with U-Shaped Resonator Assembly

Chiral structure can be applied to construct metamaterial with negative refractive index (NRI). In an assembly of double-layered metallic U-shaped resonators with two resonant frequencies $\omega _{H}$ and $\omega _{L}$, the effective induced electric and magnetic dipoles, which are contributed by the specific surface current distributions, are collinear at the same frequency. Consequently, for left circularly polarized light, NRI occurs at \textit{$\omega $}$_{H}$ , whereas for right circularly polarized light it occurs at \textit{$\omega $}$_{L}$. Our design provides a new example to apply chiral structures to tune electromagnetic properties, and could be enlightening in exploring chiral metamaterials.