Investigation of wide-angle thin metamaterial absorber at infrared region

Abstract:

In the practical application, a wide-angle absorption with simple structure is still crucial property of metamaterial absorbers (MAs). A single-band infrared MA is introduced to analyze the angle insensitive mechanism. Numerical simulation reveals that a perfect absorption peak with 99.9% (7.55 μm) is achieved at normal incidence, as well as the absorptivity is respectively 69.7% (7.46 μm) and 93.5% (7.46 μm) for transverse electric (TE) and transverse magnetic (TM) modes at 70° incidence. By changing substrate thickness, the absorption ratio at 70° is increased to 91% (7.46 μm) for TE mode. Our design can also keep the good absorption stability for the geometric parameters. The Ez-field distributions for different incident angles are given to investigate the physical mechanism. The designed MA can realize good wide-angle tolerance. This MA owns great applications, including infrared spectroscopy, solar harvester and plasmonic sensors.