Ultra-broadband large-scale infrared perfect absorber with optical transparency

We propose a metamaterial that behaves like a thermal blackbody at wavelengths from 8 to 16 mu m, and more interestingly, is transparent at visible frequencies. Our design is simple and can be fabricated cost-effectively in large scale. More than 90% absorptivity in far infrared and more than 80% average transmittance at visible frequencies are achieved experimentally with the metamaterial fabricated on an 80-cm-diameter substrate. We believe that this optically transparent infrared absorber with nanoscale thickness is promising for applications such as visible-radiation-controlled infrared absorption or solar cell radiative cooling. (C) 2017 The Japan Society of Applied Physics