Optically transparent and single-band metamaterial absorber based on indium-tin-oxide

This article proposes and experimentally demonstrates an optically transparent and polarization-insensitive metamaterial absorber in the terahertz (THz) frequencies. The absorber is formed by indium-tin-oxide (ITO) resistive films, providing efficient absorption with absorptivity of 94.1% at the peak absorption frequency of 120.8 GHz. We systematically investigate the surface current distribution and the power loss analysis, and explain the architecture of the absorber. Moreover, the absorber exhibits unique absorption properties at resonant frequencies, that is, featuring single-band or dual-band operation by changing the surface resistance of the ITO patterns. In addition, the experimental demonstration and measurement results are in good agreement with the simulated results. Most importantly, the fabricated absorber exhibits an optical transparency above 70% over the entire visible waveband, thereby enabling a wide range of applications such as optically transparent THz absorbers and detectors.