Frequency-tunable terahertz absorbers based on graphene metasurface

Circuit modeling of ultra‐broadband terahertz absorber based on graphene array periodic disks

“…[2][3][4][5] In application point of view, THz metamaterial absorbers, the artificial subwavelength composite materials, play a key role in various types of devices, and the THz spectra have the potential of realizing these devices; some of the branches of these applications are indoor communications, sensing, biosensing, filtering, imaging, and medical applications. [6][7][8][9][10][11][12] However, the requirement of some applications is tunable narrowband THz absorbers, 13 while the requirement of the others is ultra-broadband absorbers, 14,15 and research in this area is ongoing. [16][17][18] Various geometrical structures including circular patches, 19 ring arrays, 20 graphene stacks, 21,22 rectangular fish-scale, 23 cascade metal-dielectric pairs, 24 and specific ring resonator 25 have been proposed to achieve ultra-wideband or broadband absorption.…”

Implementation of Atomically Thick Graphene and Its Derivatives in Electromagnetic Absorbers

“…In addition, by varying the chemical potential of graphene, some metasurface absorbers also exhibit switching performance and operate as either fine absorbers or reflectors [104,113,114,128,129]. It is worth mentioning that the thick dielectric layer in the range of micrometers used in some of these theoretical calculations are impractical for electrostatic doping [22,27,28,113]. Furthermore, in some works, the effects of interconnecting wires between unit cells for the implementation of external bias voltage have not been taken into consideration, resulting in great uncertainty in the actual performance of the absorbers [22,28,108,111,[129][130][131][132].…”

“…Meanwhile, graphene-based reconfigurable EM absorbers have also been proposed, paving the way for the development of smart EM absorbing materials. [20][21][22][23][24][25][26][27][28][29][30][31]. Generally, there are two types of graphene EM absorbers, namely, quarter-wavelength absorber and metasurface absorber.…”

Reprogrammable multifocal THz metalens based on metal–insulator transition of VO2-assisted digital metasurface

“…Metasurfaces, the two-dimensional version of metamaterials, have recently attracted significant consideration due to their ability to manipulate arbitrary electromagnetic wavefronts by adding extraordinary field discontinuities over the interface [1,2]. Planar equivalents of conventional bulky optical devices such as lenses [3,4], holograms [5,6], absorbers [7,8], optical signal processors [9], beam deflectors [10][11][12], polarizers [13], and so on have been experimentally demonstrated in different electromagnetic frequencies. These devices consist of a subwavelength element arranged on a two-dimensional surface with a specific order.…”