Metal-graphene stacking structure for dynamical tunable ultra-wide band absorbers

By construction metal-graphene metamaterial with simple gold strips parallel or side-by-side arranged on a monolayer graphene as molecular cells, multi-band and ultra-wide band absorber can be achieved at mid-infrared frequencies. The extremely absorption bandwidth up to 11.8THz can be obtained, the intensity exceeds 90% at the absorption peak. Independently tunable multi-band and ultra-wide band absorber is also explored by stacking molecular cells with two or three layers. The results will benefit the integrated micro-structure research with flexible tunability, and the multilayer structure has potential applications in tunable filtering, sensing, cloaking objects and other multispectral devices.