Wafer-scale metamaterials for polarization-insensitive and dual-band perfect absorption

Mid-infrared (IR) perfect absorbers have great potential in practical applications such as biomedical sensing and thermal energy and have been successfully demonstrated in a number of plasmonic metallic nanostructures. However, all the experimental realizations of perfect absorbers are strongly dependent on nanofabrication techniques, which usually require high costs and a long time to fabricate a wafer scale device. Here we propose and experimentally demonstrate a wafer scale, polarization independent, wide angle, and dual-band IR perfect absorber. By fabricating double "E"-shaped metallic structures on a ZnSe coated gold film, a dual-band metamaterial absorber has been uniformly realized on a 2'' silicon wafer. Two absorption peaks have been realized at 18 and 27 THz, which are well consistent with the designs. We believe that our research will boost the applications of metamaterial perfect absorbers.