Design And Fabrication Of Doubleband And Broadband Perfect Absorber

Metamaterials are artificially engineered media with many unique properties that have not been found in nature. Metamaterials have many potential applications, and metamaterial absorber is the most important application. In the past few years, due to the demands of biological sensing and chemical detection, mid-infrared metamaterial perfect absorber has been proposed and fabricated. Up to date, metamaterial absorbers have been experimentally realized using electron-beam lithography method, which usually requires much higher cost and longer time and is not suitable for mass-fabrication. Therefore, achieving large-scale metamaterial absorber is the key step for their practical application. In this paper, we proposed a polarization-insensitive, wide-angle and dual-band perfect absorber. Then we fabricated it by lithography in wafer scale, which makes the cost much lower. We also proposed a polarization-insensitive, wide-angle and broadband absorber and the absorption is more than 90% in the whole band.For the dual-band absorber, we proposed a metal-dielectric-metal structure and then numerically calculated the absorption spectrum under different structure sizes with a finite-element method based commercial package(COMSOL Multiphysics). Then we designed the final structure and fabricated it by micro/nano fabrication technology such as electron-beam evaporation, lithography, inductively coupled plasma etching and stripe. At last, we measured the absorption spectrum using Fourier transform infrared spectrometer and compared the absorption spectrum with which under simulation.For the broadband absorber, we proposed a single-layer structure and then numerically calculated the absorption spectrum under different structure sizes with COMSOL Multiphysics. We also studied the absorbing mechanism of the single-layer structure. Then we proposed a dual-layer structure and studied the absorbing and coupling mechanism. At last, we proposed a multilayer structure which has a higher than 90% absorption in the certain waveband.