Broadband, ultrathin and polarization-insensitive metamaterial absorber based on a new mixing material in infrared and visible regions

In this paper, we proposed a broadband, ultrathin and polarization-insensitive metamaterial absorber which consists of three layers in the infrared and optical regions. Compared with the traditional three layers absorber, the most remarkable difference is that the metal Sn and InSb are used on the top layer at the same time. Numerical results reveal that a broadband absorption spectrum more than 90% can be achieved from the 97.0 THz to 115 THz. In addition, the perfect absorption character (484.4 THz-603.6 THz) also can be applied in the optical region by adjusting the structure parameters. The impedance matching theory and surface current distributions are investigated to explain the physical mechanism of the perfect absorption performance.