Homogeneous circular polarizers using a bilayered chiral metamaterial

We propose a homogeneous circular polarizer based on a bilayered chiral metamaterial with two enantiomeric wheel patterns. The transmitted field of an arbitrarily polarized incident wave through this bilayered structure is nearly circularly polarized with a circular polarization extinction ratio of more than 30 dB at resonance. We show that the origin of this phenomenon is the excitation of spinning electric dipoles in the wheel patterns, which blocks the transmission of one-handed circularly polarized component but exert little influence on the other. We also demonstrate that the operation bandwidth can be enhanced by stacking functional layers in the propagation direction. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3615054]