Ultra-wideband polarization-independent nano-metamaterial-based solar energy absorber in infrared, visible and ultraviolet regimes

This article presents a numerical analysis of a very thin concentric octagonal elliptical ring resonator (CORR) with a cylindrical rod optical nano-metamaterial absorber (ONMMA) that is designed to absorb solar energy in the infrared, visible, and ultraviolet ranges. The ONMMA is made of gold and nickel resonators on a quartz substrate with a gold plate ground material. The absorption rate of the ONMMA is over 90% from 593.84–829.28 THz, with an average absorption rate of 93.891%. This means that the ONMMA can absorb more than 80% of the energy in the infrared, visible, and a small portion of the ultraviolet range. It also has an absorption rate of over 75% from 226.64–853.04 THz, with an average absorption rate of 88.945%. This covers the entire visible spectrum, with a small portion in the infrared and ultraviolet regions. The design has an operational bandwidth of 200–920 THz, with an average absorption rate of 86.424%. The ONMMA achieves a maximum absorption rate of 99.866% at 705.44 THz. The design of the octagonal ONMMA ensures that it is not affected by the polarization of the incident light and can absorb energy even at oblique angles up to 60 degrees. The study also analyzed the effects of different materials and geometrical parameters on the absorption characteristics, as well as the distribution of surface current, magnetic field, electric field, and power loss. The proposed ONMMA has promising applications in infrared detection, solar cells, and multicolor imaging applications.