Tunable dual-band absorber based on hybrid graphene metamaterial in terahertz frequencies

Abstract

Two kinds of terahertz (THz) tunable absorber based on boottom-continuous graphene sheet and top-periodic grFeraphene structure were proposed and characterized. For the first absorber of continuous graphene sheet as a metal ground plate, it has two absorption peaks locating at 1.03 THz and 2.60THz under the Fermi energy of 0.8 eV. Upon varying Fermi energy of graphene layer from 0.4 eV to 1.0 eV, the two absorption peaks can be dynamically controlled and the modulation depth approached 19.7 % and 12.6%, respectively. For the second absorber of the periodic graphene structure, the two absorption peaks are shifted from 0.90 THz to 1.03 THz and 2.24 THz to 2.79 THz with increasing Fermi energy of graphene from 0.3 eV to 1.0 eV, respectively. The according modulation depth of two absorption peaks reached 16.23 % and 19.78 %. The absorption magnitude of peaks can both stay above 95% under different Fermi energy for two kinds of THz absorber. These results show that hybrid graphene metamaterial exhibited potentials to achieve high-performance tunable THz absorber, and may offer widespread applications such as biological detection and imaging.