Ultra-long-wave infrared broadband absorber based on a nano-resonant ring structure

We designed a four-layer structured absorber (Ti-Si-SiO 2 -Ti) in the ultra-long-wave infrared band. The paper applies the bare Ti-SiO 2 -Si film to determine the approximate target band of the absorber, and combined with the coupling effect of the top double-ring structure, it greatly enhances the absorber's property, which can make the absorber absorb more than 90% in the range of 14.0-26.3 µm in the ultra-long-wave infrared band. For the complex natural environment in practical applications, the absorber has excellent polarization independence and maintains excellent absorption in the incident environment from 0-60°.