Abstract
We experimentally demonstrate an ultrathin polarization rotator (PR) capable of rotating linearly polarized radiation 90 degrees in the terahertz-gap region by integrating the polarization conversion property from asymmetric split-ring resonators (ASRR5) and the polarization selectivity from S-shape resonators (SRs). This ultrathin-PR possesses a nearly complete polarization conversion up to 977% at L04 THz and a high conversion transmission coefficient of 048, enhanced by a constructive Febry-Perot interference between the ASRRs and the SRs. Furthermore, the overall thickness of the ultrathin PR is about 50 tm, only one-sixth of the incident wavelength, so that the associated optical devices can be miniaturized. The simple metal-dielectric-metal trilayered structure of the ultrathin-PR allows the tolerance of translational misalignment between the ASRRs and SRs and hence significantly facilitates the fabrication process. © 2012 SPIE.