Switchable terahertz polarization conversion via phase-change metasurface

We have designed a switchable ultrathin THz linearly and circularly reflective polarization converter (RPC) by inserting phase-change material, vanadium dioxide (VO2), into a chiral metasurface (CM). By thermally controlling of the VO
₂
phase transition, over 99.1% 90° linear polarization (LP) conversion modulation depth and dual-band linear to circular polarization (CP) conversion with ellipticity close to 1 have been obtained. These excellent properties make the composite chiral metamaterials particularly suitable for designing tunable polarization rotating devices, which can be widely used in detection, sensing and communications.