Nickel-Based Ultra-Thin Nano Architect Metamaterial Absorber for Optical and NIR Regime

This article proposed ultra-thin square ring-shaped metamaterial absorber nano-architectures for optical and near-infrared regime (NIR). The absorber structure comprises three layers of nickel-polyimide-nickel (Ni–Pi–Ni) material and accomplishes better absorption performance. It shows an absorption rate of 99% across a large bandwidth ranging from 990 to 1210 nm wavelength. Additionally, it shows high average absorptivity of 93.97% in the optical regions (380–700 nm) and 96.95% in the NIR regime (700–2100 nm) at 0° incidence angle of electromagnetic waves. The absorber exhibits polarization insensitivity and remains stable at oblique incidence angles up to 70° for both transverse electric (TE) and transverse magnetic (TM) modes. The study also investigates metamaterial properties, electric and magnetic characteristics, as well as surface current distribution to understand the absorption behavior. The main notable features of this metamaterial absorber are its wideband near-perfect absorptivity in the NIR regime and its structurally simple configuration.