▎ 摘　　要

NOVELTY - The ultra-broadband coherent perfect absorber based on graphene metasurface in terahertz band, has several basic units which are periodically arranged in the whole space. Each basic unit is provided with small cross-shaped graphene patches, the first optical medium layer, square graphene patches, the second optical medium layer and large cross-shaped graphene patches distributed from top to bottom. The optical medium layer is located between two of the three-layer graphene patch. The graphene patch of each layer is tiled on the corresponding optical medium layer. The centers of the three layers of graphene patches are overlapped. The two optical media layers are cuboids with exactly same size. USE - Ultra-broadband coherent perfect absorber based on graphene metasurface in terahertz band, used in various applications such as optical excitation, modulation, sensing and detection, and imaging applications. ADVANTAGE - The performance of the graphene is adjusted by changing the Fermi energy level of the graphene, and the dynamic adjustable characteristics of the device are realized. The single layer of graphene is used to replace the upper metal layer, so that the upper layer structure and the dielectric layer together form an all-dielectric structure, and the thickness of the graphene is much smaller than that of the conventional metal layer, the problem of excessive ohmic loss of the conventional metal layer is avoided, the absorption rate is improved, and perfect absorption is achieved. DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view showing parameter of ultra-broadband coherent perfect absorber. dThickness of the optical medium layer L1,L3Lengths of the small cross-shaped graphene patch W1-W3Widths of the square graphene patch