Numerical investigation of polarization-insensitive multiband metamaterial for terahertz solar absorber

This study presents a nanostructured multiband metamaterial absorber for the optical regime application. The proposed structure is exhibited 0° to 90° polarization insensitivity and up to 45° angular stability with more than 90% peak absorption in between 300 THz800 THz frequency range. Proposed MMA structure is acquired perfect absorption of 99.99% at 571THz, 99.50% at 488.26 THz, 99.32% at 598 THz frequency by adjusting geometrical parameters. Due to perfect impedance matching with plasmonic resonance characteristics, these structures achieved an average absorption of 95.30%, 91.96%, 97.25%, 97.65%, 91%,90%,90.23% in between (337.5 THz-346.5 THz), (471 THz-478 THz), (497.5 THz-505 THz), (519 THz-530.5 THz), 564.5 THz-577 THz), (604 THz-673 THz), (686 THz-708 THz), respectively. The near field pattern of proposed MMA is used to explain the absorption mechanism at resonance frequency point and the geometric parameters are explored and analyzed to demonstrate the performance of the proposed structure. Moreover, CST-HFSS interference is validated the simulation data with the help of the finite element method (FEM). Polarization insensitivity and wide angular stability in terahertz (THz) frequency regime make this structure suitable for the application of magnetic resonance imaging (MRI), color images, thermal imaging and solar cell applications like exploitation of solar energy.