Construction of a chiral metamaterial with a U-shaped resonator assembly

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 originate from the specific distribution of induced surface electric current upon the illumination of incident light, are collinear at the same frequency. Consequently, for left circularly polarized incident light, negative refractive index occurs at omega(H), whereas for right circularly polarized incident light it occurs at omega(L). We suggest that this design provides a new example to apply chiral structures to tune the electromagnetic properties, and could be enlightening in exploring chiral metamaterials.