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

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 subbands: 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 subbands 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.