Dual-controlled broadband terahertz absorber based on graphene and Dirac semimetal

Abstract

We proposed a dual-controlled broadband terahertz (THz) absorber based on graphene and Dirac semimetal. Calculated results show that the absorptance over 90% is achieved in the frequency range of 4.79-8.99 THz for both transverse electric (TE) and transverse magnetic (TM) polarizations. Benefiting from the advantage of the dielectric constant of these materials varying with chemical doping or gate voltage, the simulation results exhibit that the absorbance bandwidth can be controlled independently or jointly by varying the Fermi energy of the graphene or Dirac semimetal patterns instead of redesigning the absorbers. Impedance matching theory was introduced to analyze the absorption spectra changing with EF. The bandwidth and absorptivity of the proposed absorber are almost independent of changing the incident angle θ up to 35° and 40° for TE and TM modes, respectively. It works well even at a larger incident angle. Because of the symmetry of the structure, this designed absorber is polarization insensitive and almost the same absorptivity for both polarizations. Furthermore, the physical mechanisms were further disclosed by the electric field distributions. The proposed broadband and dual-controlled absorber may have potential applications in various fields of high-performance terahertz devices.

Harmonic Generation in Low‐Dimensional Materials

“…[120][121][122][123] The permittivity and the Fermi level of the 3D DSM can be efficiently controlled like in the case of graphene. [124][125][126][127] The 3D DSM is quite stable against environmental temperature more or less like graphene. [128] Many researchers have reported the 3D DSM based linear and nonlinear optical properties and devices in the terahertz and infrared region.…”

Tunable Perfect Absorber of Graphene Metamaterial in the Terahertz Band and Its Sensing Properties

“…[ 12 ] Xiong et al studied a dual‐control wideband terahertz absorber based on graphite and Dirac semimetal multilayer structure, which has adjustable wideband and bandwidth. [ 13 ] Xu et al designed a terahertz absorber based on a T‐shaped single‐layer graphene‐based structure, which can control the working frequency of the absorption peak. [ 14 ] Nevertheless, the proposed structure still has some limitations, such as complexity or low absorbance.…”

An Octaband Temperature Tunable Terahertz Metamaterial Absorber Using Tapered Triangular Structures

“…Furthermore, these spectra may be tunable or fixed. TMAs whose absorption spectra can be shifted by applying external stimuli such as voltage, mechanical stress, and temperature [10][11][12] are known as tunable TMAs. Temperature tunable TMAs are those structures whose absorption spectra can be tuned by varying the temperature.…”