Independently tunable dual-band metamaterial absorber based on graphene at mid-infrared frequencies

Despite the great achievement in understanding of the graphene-based metamaterial absorbers (GMAs), the limitations such as single narrowband absorption, low absorption peak and multiple bands that can't be independently tuned have not been completely overcome. This paper reports a dual-band absorber through etching two cascaded metallic resonators with different sizes in the unit cell of GMA. Two independently tunable absorption hands with absorption peaks greater than 99% are obtained at mid-infrared frequencies.