Ultra long infrared metamaterial absorber with high absorption and broad band based on nano cross surrounding

We propose a broad band and high absorption adjustable ideal absorber. The whole structure is Cr-Ge-Si3N4-Ti from bottom to top. The simulation results show that three resonant absorption modes are generated at 9.15 μm, 10.68 μm and 15.17 μm, with absorption rates of 92.1%, 97.3% and 95.2%, respectively. The bandwidth of the absorber is broadened by adding a lossy dielectric layer. Then, the control variables of the structural geometry parameters of the absorber were studied respectively to obtain the best optimization parameters. Since then, comparisons of different underlying microstructures have confirmed the uniqueness of our structure. Finally, we simulate the absorption of the absorber in different polarization modes with varying incident angles. In addition, the performance of previous work and our absorber are compared. These studies show that our absorber has active tunability, polarization and incident angle sensitivity, and high absorption bandwidth.