Study on a simple long-wave infrared ultra-wideband metamaterial absorber with a high tolerance of manufacturing errors

Among the electromagnetic bands, the infrared band occupies a crucial place due to its wide range. Absorption in the long-wave infrared band is an important focus of infrared research and has attracted a great deal of attention from researchers. In this work, a long-wave infrared ultra-wideband absorber based on a four-layer metal-dielectric-metal-dielectric structure is proposed. In the ultra-long operating band of 8-36 mu m, the average absorption rate is as high as 95.79 %, brought about by the resonance excitation of various modes, including local surface plasmon resonance, guided mode resonance, cavity resonance, magnetic resonance, and diffraction. At a large incidence angle of 60 degrees, the absorption of the absorber can reach 91.17 % in TE mode, demonstrating insensitivity to large-angle incidence. At 1800 K, the absorber shows an emission efficiency as high as 97.01 % in the long-wave infrared range. It is worth mentioning that our absorber exhibits an extremely large manufacturing tolerance of +/- 0.4 mu m, making it highly suitable for practical production and application. Therefore, the proposed absorber shows promising potential in applications such as infrared imaging, infrared detection, hot electron collection, radiative cooling, and other related fields. In addition, the absorber can be used in remote sensing applications, as its operating band effectively covers the common remote sensing band from 8 to 30 mu m.