Chiral metamaterials with negative refractive index based on four U split ring resonators

A uniaxial chiral metamaterial is constructed by double-layered four U split ring resonators mutually twisted by 90 degrees. It shows a giant optical activity and circular dichroism. The retrieval results reveal that a negative refractive index is realized for circularly polarized waves due to the large chirality. The experimental results are in good agreement with the numerical results. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3457448]