Actively switchable polarization converter for reflection and transmission in the same terahertz frequencies

A metamaterial-based dual-function switchable polarization conversion device working in terahertz frequency regime is proposed and verified by both numerical methods of finite element method and finite difference time domain. Based on phase transition of vanadium dioxide component from dielectric state to metal state, the transmissive–reflective switching function with high polarization conversion ratios (above 90%) simultaneously can be achieved in the same frequency domains (from 5.30 to 10.70 THz). In the meantime, the transmitted–reflective coupling effects and transmitted polarization-sensitive merit can be illustrated by distributions of surface currents and electric fields, respectively. According to the interesting results, the flexible polarization conversion with a switching function shows great potential application prospects in polarization-related communication and switching devices. Graphical abstract