Tunable bandwidth of the terahertz metamaterial absorber

We propose a broadband terahertz metamaterial absorber that utilizes the coupling effect of the sub-unit elements of the structure consisted of two asymmetric metallic square rings and a metallic ground plane separated by a dielectric layer. The bandwidth of the absorber is tunable over a range from 0.88 to 1.28 THz by the coupling distance of the two patterned square rings. The proposed absorber has the tunability from broadband to single-band by the polarization angle of the system. Moreover, the proposed concept also applies to other types of asymmetric absorber structure and can be readily extended to other frequency regimes for a host of applications such as detection, imaging and solar cell.