Multi-band multi-tunable perfect plasmon absorber based on L-shaped and double-elliptical graphene stacks

In this paper, a multi-band multi-tunable graphene absorber structure is proposed. The absorber is made by "+" intersecting double-ellipse graphene, L-shaped graphene layer, medium layer, the metal layer, and Si substrate. By using this structure, we investigated the possibility of graphene surface plasmon resonance in the incident far-infrared wave and THz wave range. For this structure, we use the FDTD Solution of finite time domain difference software to conduct theoretical research on it. The results show that the absorbing device in the range of the infrared in lambda(1) = 10.78 mu m, lambda(2) = 12.20 mu m and lambda(3) = 21.74 mu m show perfect absorption peak of absorption rate is as high as 99.97%, 99.81% and 99.91%, respectively. By controlling the Fermi level or the geometric parameters of the graphene layer can dynamically adjust the resonant wavelength of absorbing device, and polarization insensitivity characteristics. And in TE or TM mode, it can maintain good absorption performance in a wide range of 0 degrees similar to 60 degrees. We believe that our research results will open new doors for the use of metamaterial absorbers with multi-band, multi-tunable, polarization-independent and insensitive to large-angle oblique incidence. In the future, it can be used in photoelectric detection, photovoltaic cells, photoelectric sensors, photoelectric thermal radiation and other fields.