Circular conversion dichroism in planar chiral metamaterials
  We report the first experiential observation and theoretical analysis of the new phenomenon of planar chiral circular conversion dichroism, which in some aspects resembles the Faraday effect in magnetized media, but does not require the presence of a magnetic field for its observation. It results from the interaction of an electromagnetic wave with a planar chiral structure patterned on the sub-wavelength scale, and manifests itself in asymmetric transmission of circularly polarized waves in the opposite directions through the structure and elliptically polarized eigenstates. The new effect is radically different from conventional gyrotropy of three-dimensional chiral media. 
V. A. Fedotov, P. L. Mladyonov, S. L. Prosvirnin, A. V. Rogacheva, Y.   Chen, N. I. Zheludev