Wideband perfect absorption based on metamaterial in near-infrared range. (July 2020) - Ju, Lu
Abstract: A new design for expanding the absorption band of absorber in near-infrared range is theoretically proposed. This design is achieved by a layered cascade metamaterial structure that consists of four metamaterial slabs. A single metamaterial slab is made of a periodic array of tilted metal layers. The results show that the layered cascade structures obviously broaden the widths of the absorption bands. The transfer matrix is derived according to the special properties of the structure designed in the paper, and the absorption of the design is numerically simulated using the transfer matrix method. The influence of structural parameters on the absorption properties of metamaterial layer is analyzed: the locations of the absorption peaks are red-shifted with the increase of the inclination angles of the metal layers and the distance between the metal layers. The positions of the absorption peaks are blue-shifted with the increase of the thicknesses of the metal layers. The widths of the absorption bands increase while the centers of absorption peaks remain the same with the increase of the thicknesses of the metamaterial slabs. According to the above results, the metamaterial slabs which contain similar structural parameters are selected to constitute a layered cascade structure. The absorption of the layered cascade structures is numerically simulated and theoretically analyzed. The simulation results show that the absorption bands are obviously widened and the multi-band absorption peaks are found in the near-infrared region with the superposition of different suitable materials. Highlights: A new design for broadening the absorption band of an absorber in the near-infrared range is theoretically proposed. This design is achieved by a layered cascade metamaterial structure that consists of four metamaterial slabs. A single metamaterial slab is made of a periodic array of tilted metal layers. The results show that the layered cascade structures obviously broaden the absorption bands.