Design and Analysis of Plasmonic Solar Absorber for Visible and Infrared Spectrum

In this study, a periodic array of square bar-shaped nickel (Ni) metal is presented as a straightforward and cost-effective broadband absorber spanning the visible to mid-infrared spectrum. The proposed square bar-shaped nanoabsorber (SBNA) holds a simple and single-layer design topology, which contains plasmonic metal at the top and bottom side of the middle dielectric spacer. The metallic layers are composed of plasmonic Ni, while a dielectric spacer, aluminum nitride (AlN), is employed. The absorption characteristics of the proposed SBNA are evaluated using the full-wave simulation software CST Studio. The SBNA exhibits a broad absorption bandwidth spanning from 200 to 3500 nm, encompassing the ultraviolet (UV) to the short-infrared spectrum. Moreover, an angular stability analysis of the designed SBNA is conducted by considering both the excitation modes (TE and TM). The absorption properties of the SBNA remain the same under the variation of polarization angle; it is owing to the fourfold symmetric configuration of the absorber. The effective engineering of design parameters, including the length of the square-shaped nano-bar, spacer thickness, and periodicity of the unit cell, significantly influences the absorption window. In conclusion, the designed SBNA holds significant potential for diverse applications such as energy harvesting, optical emission, and thermal photonics.