Strong optical activity in chiral metamaterials of metal screw hole arrays

The authors demonstrate the change of the polarization of the electromagnetic wave induced by chiral metamaterials in the terahertz region. The polarization of the incident terahertz wave changes dramatically after transmitting through the chiral metamaterials made of the array of screw holes in metal slabs. A strong resonant polarization change (ellipticity and polarization azimuth) is observed at frequencies corresponding to the standing cavity modes of the metal waveguide with a finite length. Such experimental results indicate that the metal screw hole arrays work as a strong optically active material. (c) 2006 American Institute of Physics.