A multifunctional switching bidirectional optical absorber based on a titanium nitride metamaterial

In this paper, a novel type of tunable ultra-wide band and double-narrow band artificial electromagnetic absorption device is studied. This work uses a titanium nitride-titanium-tungsten (TiN-Ti-W) composite ring array, a TiN reflector layer, and a silver-titanium dioxide-silver (Ag-TiO₂-Ag) three layer composite structure to prepare the absorption layer. The simulation results illustrate that the absorption rate can reach 96.6% when the absorption wavelength is 300-2800 nm. When the light source is backward incidence, ultra-narrow band absorption can occur at specific wavelengths of 465 nm and 932 nm. This proves that the absorber is in good agreement with the impedance matching theory. The research results of this work will provide a theoretical basis for the design and application of solar thermal energy conversion.