Polarization-insensitive infrared-visible perfect metamaterial absorber and permittivity sensor

Abstract

Abstract In this work, a new multi-circular ring perfect metamaterial absorber (PMA) with unity solar energy absorption in the infrared and visible frequency ranges is proposed. Its absorption characteristics are strongly affected by various factors, including the devices size, substrate materials, polarisation effects in the transverse electric and transverse magnetic modes, substrate thickness, resonator effects. In the designed PMA, perfect absorbance is obtained by using a multi-circular ring with low conductivity aluminum metallic patterns and a gallium arsenide dielectric substrate. The commercially available CST microwave studio based on a finite integration technique and High Frequency Structural Simulator (HFSS) are utilised to investigate the absorption parameters of the proposed structure. The PMA absorbance spectrum covers both the infrared and visible frequencies due to the excitation of different magnetic and electric modes. In addition, the PMA application as a permittivity sensor is examined as well. It exhibits almost perfect absorbances equal to 99.74% and 99.23% at 245.03 and 376.13 THz in the infrared region and 99.82% at 502.10 THz in the visible region, respectively. The results of numerical simulations demonstrate that the proposed configuration is insensitive to polarisation angle. Hence, the designed metamaterial absorber is characterised by the perfect absorption in the infrared and visible frequency ranges and can be used for renewable solar energy harvesting as well as, for stealth technology, sensing, and imaging applications.