Manipulating polarization states of terahertz radiation using metamaterials

We present a double-ring-chain metamaterial that enables efficient polarization conversion of terahertz waves. The experimental results and numerical simulations reveal that the linear-to-linear polarization rotation and linear-to-elliptic polarization transformation are simply accomplished by altering the dimensional parameters of the metamaterial unit cells. The polarization state conversion is found to be critically related to the resonant properties of the long bars and the rings in the unit geometries and is well described by the Jones matrix. This approach promises both passive and active polarization conversion of terahertz radiation using planar metamaterials.