Mohd Farman Ali, Abhishek Kumar, Gaurav Varshney
A combination of vanadium dioxide (VO2) resonators assisted by a graphene sheet operating with multiple resonances can provide a way to electrically separate and merge the resonance spectrum. The device operation can be set to multifunctionality through electrical variation by generating multiple narrow and broad absorption peaks together. VO2allows to provide the thermally switchable absorption response. The adequate Fermi energy of graphene can excite the resonances with an electrically controlled phase. Hence, tunable out-of-phase resonances can be achieved along with the in-phase resonances. The spectrum of out-of-phase resonances remains separated with a narrow line shape. In addition, in-phase resonances provide a wideband due to their merged spectrum. A thin dielectric loading above the absorber can further excite a greater number of the out-of-phase resonances to generate the multiple narrow absorption peaks along with the broad absorption band. An ultrathin geometry of thickness around$\approx \lambda $/215 is achieved;$\lambda $is the free space wavelength. The proposed absorber can be used in sensing and shielding applications at terahertz (THz) frequency.