Perfect absorption and polarization conversion metasurface based on graphene and vanadium dioxide

Abstract A dual-functional metasurface based on graphene and vanadium dioxide (VO 2 ) was proposed. In the instance that VO 2 is in insulating state and the Fermi level ( E F ) of graphene is tuned to be 1.2 eV, the metasurface works as an absorber. Simulation results demonstrate absorption exceeding 90% across the broad bandwidth of 3–7.47 THz, with near-perfect absorption greater than 99% achieved in two sub-bands: 3.43–3.82 THz and 5.4–7 THz. Furthermore, the absorption characteristics can be dynamically tuned by controlling the E F of graphene. On the other hand, when E F = 0 eV and VO 2 transitions to its metallic state via a thermal phase change, the metasurface exhibits the function of a polarization converter. Simulations reveal a linear polarization conversion ratio (LPCR) exceeding 0.9 across an ultra-broad bandwidth of 4.85–12.9 THz, with near 100% polarization conversion ratio (PCR) within the two sub-bands of 5.3–5.4 THz and 9.5–12.4 THz. Moreover, the metasurface exhibits robustness against fabrication errors, variations in incident angles, and different polarization modes. These electromagnetic (EM) properties highlight its potential applications in communication components and optical coatings.