Band reduplication of perfect metamaterial terahertz absorber with an added layer: cross symmetry concept

• Published in: Optical and quantum electronics 2023-05, Vol.55 (5), Article 391
• Main Authors: Zamzam, Pouria, Rezaei, Pejman, Mohsen Daraei, Omid, Khatami, Seyed Amin
• Format: Article
• Language: English
• Subjects: Absorbers; Absorbers (materials); Absorption spectra; Banded structure; Characterization and Evaluation of Materials; Computer Communication Networks; Electrical Engineering; Graphene; Lasers; Metamaterials; Optical Devices; Optics; Photonics; Physics; Physics and Astronomy; Symmetry; Unit cell
• ISSN: 0306-8919; 1572-817X
• DOI: 10.1007/s11082-023-04561-x

In this paper, one of the necessary and fundamental conditions for using an additional layer to obtain more absorption bands in metamaterial absorbers is determined. We consider the case in classical 3-layer absorbers (usually made of metal-dielectric-metal) that use graphene in their upper layer. If the form or pattern of the upper layer has cross-symmetry, a dual-band or multiband absorber will be achieved by adding another layer. In the present literature, there is no specific regulation for improving the absorption performance of terahertz absorbers by adding a layer, and there are only ad hoc working examples. Because the multi-band absorbers have greater tuneability and are more efficient than the single band absorbers, the ability to design for a higher number of bands is of practical significance. Note that this phenomenon is achieved only by adding one layer of graphene-shaped structures on the surface without manipulating the dimensions of the unit cell or the material of each component. This concept has been studied on the absorption performance of three basic structures. This increment in the number of absorption bands is true for all absorbers with cross-symmetry forms.