A perfect metamaterial polarization rotator

TLDR

Polarization carries valuable information for electromagnetic signal processing and has attracted extensive research interest, especially in the terahertz regime. The study proposes a unique broadband approach to efficiently rotate linear terahertz polarization using tri‑layer metasurfaces. High transmittance and polarization rotation arise from a Fabry‑Perot cavity effect within the tri‑layer metasurfaces. Experimentally, the device achieves nearly perfect orthogonal polarization conversion with ultrahigh efficiency, demonstrating an ultrathin terahertz rotator.

Abstract

Polarization conveys valuable information for electromagnetic signal processing exhibiting tremendous potential in developing application driven photonic devices. Manipulation of polarization state of an electromagnetic wave has drawn a lot of research interests in many different fields, especially in the terahertz regime. Here, we propose a unique approach to efficiently rotate the linear polarization of terahertz wave in a broadband configuration with tri-layer metasurfaces. We experimentally observe a nearly perfect orthogonal polarization conversion with an ultrahigh efficiency, demonstrating a ultrathin terahetz rotator. The Fabry-Perot cavity effect in the tri-layer metasurfaces is attributed to the underlying mechanism of high transmittance and polarization rotation.