Investigation of wide-angle thin metamaterial absorber at infrared region

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%(7.55μm)is achieved at normal incidence,as well as the absorptivity is respectively 69.7%(7.46μm)and 93.5%(7.46μm)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%(7.46μm)for TE mode.Our design can also keep the good absorption stability for the geometric parameters.The E z-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.