Ultra-Broadband Dual-Square Ring  Metamaterial Absorbers from Visible to Far-Infrared Region

In this paper, we have theoretically proposed and numerically verified an ultra-wideband (UWB) metamaterial absorber based on dual-square ring (DSR) microstructures from the visible to the far-infrared region. The top of the absorber is a DSR nested structure composed of chromium and nickel. The bottom chrome is separated by an intermediate dielectric layer. The results of the simulation indicated that the designed metamaterial absorber achieved more than 90% absorption from 1200 nm to 11000 nm wavelength range. In addition, in the operating wavelength range of 500-13,000 nm, the absorption rate is greater than 80%, achieving ultra-broadband absorption with a bandwidth of over 12,000 nm. Based on the principle of plasmonic multi-level resonance and the resonator coupling effect, our proposed metamaterial absorber receives a significant improvement in absorption bandwidth compared with previous work. In addition, the absorber has many advantages such as polarization insensitivity, Wide angle absorption, excellent stability and corrosion resistance. The designed UWB absorber supports promising applications in the fields of thermal photovoltaic power generation, infrared imaging, photoelectric detection and other fields.