Electric field-induced switching of bands in graphene-assisted metamaterial absorber

A dual-band metamaterial absorber based on graphene is designed and numerically analyzed for operation at near-infrared frequencies. The structure comprises a one-dimensional silicon grating placed on a single layer graphene, supported by a gold substrate. The working mechanisms of the absorber are understood with the help of numerical simulations, which are performed using Computer Simulation Technology (CST) Microwave Studio. The simulation results indicate that the critical coupling enabled through the guided-mode resonance in the system significantly enhances the dual-band absorption. The absorber demonstrates two narrow absorption bands with corresponding absorptances of about 1 and 0.97 at wavelengths of 665.58 nm and 1134 nm, respectively. The number of absorption bands in this design can be electrically adjusted by leveraging the tunable conductivity of graphene. The absorber can be used as a dual-band absorber/single-band absorber or alike a perfect reflector. The aspects of different geometrical parameters like periodicity, width of the grating ridge, height/depth of the grating ridge and chemical potential of graphene are investigated in detail. Given its dual resonance wavelengths, high absorptance, and tunable band-switching capability, this absorber shows great potential for various applications at near-infrared frequencies. © 2024 Elsevier GmbH