Design and analysis of quad-band polarization-insensitive infrared perfect metamaterial absorber with a wide-incident angle

There is a pressing demand to design simple absorber structures that support optimal absorption in multi-band to meet different applications. In this work, a novel quad-band infrared perfect metamaterial absorber (QPMA) is proposed and numerically investigated. The structure of the QPMA is composed of coaxial multi-layer dielectric (SiO2) disks of circular shape with different diameters where each disk is surrounded by a gold ring. All disks are placed on a SiO2 dielectric spacer and an impermeable gold ground layer. Simulation results reveal that the proposed absorber has four absorption peaks around wavelengths of 1064 nm, 1550 nm, 2080 nm, and 3000 nm. Since these wavelengths correspond to commercially available laser sources, the structure under investigation can be used in different applications such as laser stealth, infrared photodetection, and medical applications. Additionally, the QPMA structure enjoys a good absorption performance for a wide range of incident angles for both TE and TM waves. It achieves absorption greater than 85% at incident angles up to 40° at 1064 nm, and absorption greater than 90% for the other bands at incident angles up to 50°. Moreover, due to the symmetrical shape of the structure, the absorption is insensitive to wave polarization changes.