Investigation of graphene-supported submillimeter adjustable metamaterial absorbers

Abstract

Based on a graphene ribbon resonator, the tunable resonant properties of metamaterials (MMs) have been symmetrically investigated in the submillimeter region, including the effect of the graphene Fermi levels, rotation angles, incident angles, and polarization angles. The results manifest that the proposed graphene ribbon MMs indicate a high Q-factor of more than 20. The Fermi level significantly affects the resonant curves; obvious resonant peaks can be observed if the Fermi level is larger than 0.20 eV, and the resonant strength increases with the Fermi level. For instance, for single graphene ribbons, the absorption modulation depth (MD) is about 22.60% on the condition that the Fermi level changes in the range of 0.1–1.0 eV, and the absorption amplitude MD reaches about 93.85% if the rotation angles of the graphene ribbon degree change in the range of 0–90 deg. Additionally, by using triple graphene ribbons with different lengths, multiple resonant peaks (0.22 THz, 0.345 THz, and 0.46 THz) can be achieved simultaneously. Apart from the good tunable properties, the amplitude MD is about 76.6% (82.18%) if the incident (polarization) angle of the THz wave changes in the range of 0–90 deg. These results can help us better understand the tunable mechanisms of graphene metamaterials and design high performances devices such as light absorbers, detectors, and sensors.