Switching between the Functions of Half-Wave Plate and Quarter-Wave Plate Simply by Using a Vanadium Dioxide Film in a Terahertz Metamaterial*

We propose a switchable THz metamaterial that can be switched between two functions of half-wave plate and quarter-wave plate. The two switchable functions can be simply achieved by inserting a VO(2)film in the metamaterial design. Finite-difference time-domain (FDTD) simulation results show that the proposed metamaterial can convertx-polarized incident wave toy-polarized reflected wave when VO(2)is at metal phase, and convertx-polarized wave to circularly polarized wave when VO(2)is at insulator phase. The metamaterial performs well in the two functions, i.e., the same broad working frequency band and near perfect polarization conversion. The switching effect originates from the switchable Fabry-Perot cavity length induced by the phase change of VO2. We believe that our findings provide a reference in designing switchable metamaterials.