Electrically-tunable active metasurfaces and metadevices based on phase transition of vanadium dioxide

In recent years, dynamically tunable nanophotonic materials and devices have drawn intense attention with great promise for practical applications. In this work, we present several electrically-tunable active metasurfaces and metadevices based on the phase transition of VO₂, which include electrically tunable broadband infrared waveplates with dynamic metasurfaces, continuously and reversibly electro-tunable optical nanoantennas, and electrically-tuned flexible active absorbers. First, we experimentally demonstrate the electrically-tunable broadband infrared waveplates by combining phase-change material (VO₂) and dispersion-free metasurface. The polarization states are modulated through the electrically-induced phase transition of vanadium dioxide, where the output polarization state can be continuously tuned from horizontal polarization to vertical polarization, or from circular polarization to linear polarization. In the second, we experimentally demonstrate a continuously and reversibly electro-tunable optical nanoantenna, by integrating an asymmetric gold nanodisk dimer array with a vanadium dioxide film. Thirdly, we have demonstrated a metal-flexible PCM(VO₂)-metal infrared meta-absorber with mechanical flexibility and electrical tunability. The investigations here can be applied in dynamic digital displays, optical data storage, imaging sensors, and active wearable devices.