Dual-tunable graphene–vanadium dioxide metasurface for adaptive terahertz wavefront control and electromagnetic interference suppression

Abstract

Abstract. The development of advanced terahertz systems requires compact and reconfigurable devices capable of adaptive wavefront manipulation and electromagnetic energy control. In this work, we propose a dual-tunable VO2–graphene coding metasurface that integrates thermally switchable vanadium dioxide and electrically tunable graphene within a multilayer unit-cell structure. The VO2 phase transition enables switching between reflection and absorption operation modes, while the graphene Fermi level provides active control of the reflection phase and absorption response. In the reflection mode, four discrete coding states are obtained by tuning the graphene Fermi level, and the reflection amplitudes remain above 0.7 within 5.4 to 5.6 THz. The phase differences between adjacent coding states are close to 90 deg, enabling 2-bit programmable beam manipulation. Based on 1-bit, 2-bit, and convolution-based coding strategies, the proposed metasurface realizes specular reflection, dual-beam splitting, four-beam scattering, and anomalous single-beam deflection, with the maximum elevation deflection angle reaching 26 deg. In the absorption mode, when VO2 is in the insulating state, the structure exhibits dual-band absorption near 1.2 and 2.6 THz, with the maximum absorptance reaching 99.8% under graphene Fermi-level tuning. A fabrication-oriented integration route is also discussed by considering graphene transfer, VO2 patterning, dielectric isolation, and separated thermal/electrical control channels. The simulation results indicate that the proposed VO2–graphene metasurface provides a feasible platform for adaptive terahertz wavefront control, reflective modulation, multiband absorption, and electromagnetic interference suppression, showing potential for smart THz imaging, modulation, and sensing systems.