Complementary graphene metamaterial with independently tunable dual absorption bands at terahertz frequency

We design an independently tunable dual-band terahertz absorber consisting of graphene ribbons patterned with a combination of two complementary crosses of different sizes within a unit-cell. The Fermi energy of the interdigitated graphene ribbons can be tuned independently via applied gate voltages. Our simulations indicate that the absorption at two resonant bands can be similar to 75% under normal incidence. In addition, our design allows independent tuning of the resonant frequencies by changing the Fermi energy of graphene via controlling the applied bias voltages. Our results may find application in developing frequency tunable terahertz modulators, sensors, and detectors.