Dynamically tunable broadband linear-to-circular polarization converter based on Dirac semimetals

Abstract

We propose a dynamically tunable broadband linear-to-circular cross polarization converter based on Dirac semimetals. The proposed converter unit cell consists of a center-cut cross-shaped metallic patterned structure with a sandwiched Dirac semimetal ribbon on a polyimide substrate bottomed with gold. The proposed system converts linear waves to right-hand circular polarized waves in the frequency ranges of 1.5–2.8 THz or to left-hand circular polarized waves in two narrow frequency ranges of 1.20–1.25 and 3.04–3.07 THz. The polarization conversion is dynamically tunable by varying the Fermi energy without re-optimizing the microstructures, which may further tunable polarizers and polarization switchers developments.