A metamaterial absorber with a multi-layer metal-dielectric grating structure from visible to near-infrared

In this paper, we propose a multi-layer metal-dielectric grating consisting of multi-layer nickel-silicon nitride (Ni-SiNX) grating over a metallic Ni substrate as an ultra-broadband near-perfect absorber. The structure is not only simple in structure, but also superior in performance. Numerical analysis of the structure shows that it has an absorption rate of 99.24% in the wavelength range of 400-2000 nm. To achieve ultra-broadband and high absorption properties, the suggested absorber simultaneously creates excitation of propagating surface plasmon resonance (PSPR), local surface plasmon resonance (LSPR), and Fabry-Perot (FP) cavity. By analyzing the absorption performance of different incident angles and polarization waves, it is demonstrated that the broadband near-perfect absorption of the absorber exhibits insensitivity to the angle of the incident light. In addition, we discuss the effects of various metallic materials and parameters of geometric structures on the absorption characteristics in detail. Finally, we discussed the suggested scheme's potential in terms of solar energy capture. Therefore, we anticipate that our proposed absorber can be applied in solar energy harvesting as well as broadband thermal emission.