Polarization Selective Broad/Triple Band Absorber Based on All-Dielectric Metamaterials in Long Infrared Regime

In this paper, a polarization selective broad/triple-band metamaterial absorber based on SiO2 all-dielectric is designed and studied. The absorber works in a long infrared band (8-14 mu m). It is composed of cuboid and trapezoidal silica structures in the upper layer and metal plates in the lower layer. We calculate the absorption results of the metamaterial absorber at different polarization angles as the polarization angle of incident light increases from 0 degrees to 90 degrees; that is, the light changes from Ex polarization to Ey polarization. The results show that the absorption rate of the structure is more than 90% in the range of 8.16 to 9.61 mu m when the polarization angle is 0 degrees. When the polarization angle of the incident light is less than 45 degrees, the absorption result of the absorber does not change significantly. When the polarization angle of the incident light is greater than 45 degrees, three absorption peaks appear in the long infrared band, realizing the selectivity of the polarization of the incident light. When the polarization angle increases to 90 degrees, the absorptivity of the two absorption peaks at lambda = 9.7 mu m and 12.3 mu m reaches more than 85%. In addition, the sensitivity analysis of the length, width, and thickness of the all-dielectric metamaterial absorber and the calculation of the electric field of this structure are also carried out. The designed all-dielectric metamaterial absorber has polarization selection and perfect absorption characteristics and has a broad application prospect.