A Multi-Band Near Perfect Polarization and Angular Insensitive Metamaterial Absorber With a Simple Octagonal Resonator for Visible Wavelength

A multi-band, ultrathin, polarization-insensitive, near-perfect metamaterial absorber (PMA) has been proposed and substantiated numerically for solar thermophotovoltaic (STPV) systems which also can be used in some other applications. This kind of absorber currently drawing massive interest throughout the research of optics. Especially in solar harvesting metamaterial absorbers can give a huge boost in efficiency by intensifying the solar electromagnetic wave. Visible wavelength has been the key focus of the proposed design so that the structure can utilize solar energy proficiently. Aluminum (Al) and Gallium Arsenide (GaAs) have been chosen as materials for their higher electron mobility along with good temperature stability. The PMA is a three-layer metal-dielectric-metal called sandwiched structure. For proper characterization of the PMA absorber, extensive parametric inspections were carried out with underlying physics. The finite integration technique (FIT) in computer simulation technology microwave studio (CST MWS) is used to perform the numerical analysis and for verification finite element method (FEM) in COMSOL Multiphysics has been used along with interference theory model (ITM) for calculating the absorbance. The PMA shows 99.27%, 99.89%, 99.91%, and 99.06% perfect absorption at 454.75nm, 505.53nm, 568.72nm, and 600.85nm resonance wavelength in all three modes of waveguide propagation. The design also exhibits incident wave stability up to 60 degrees for both transverse electric (TE), and transverse magnetic (TM) wave modes. Excellent glucose concentration sensing ability was also observed with the proposed structure. So, the proposed PMA can be implemented in solar energy harvesting devices along with solar sensors or detectors, light trappers, light modulators, or light wavelength detectors.