Graphene-Assisted Narrow Bandwidth Dual-Band Tunable Terahertz Metamaterial Absorber

Abstract

A tunable graphene terahertz metamaterial absorber is designed by treating a monolayer continuous dumbbell-shaped structure graphene layer, which can simultaneously realize the narrow bandwidth and dual-band absorption with transverse magnetic (TM) polarization and wide incident angle operation. Two pronounced absorption peaks are caused by the novel toroidal dipole phenomenon and magnetic plasmon polariton. By optimizing the geometry parameters, the relative narrow bandwidths of the two absorption peaks are 26.4 and 23.5 GHz at frequencies of 0.2242 THz and 0.5302 THz, respectively, with the absorption rate above 99.6%. Since the continuous dumbbell-shaped graphene structure is treated in the absorber, a more convenient way to realize the tuning ability by treating a bias voltage compared to the absorbers with discrete graphene structures. The designed device can work at a wide incident angles (up to 80 •) under TM polarization with the absorption above 88% at low frequency. The simulation results are basically in good agreement with the results of the equivalent circuit model. This work offers huge potential applications in terahertz imaging, detecting and sensing, especially in the 6G communication systems.

A Review: The Functional Materials-Assisted Terahertz Metamaterial Absorbers and Polarization Converters

“…The frequency and intensity of the absorption peaks can be modulated based on the variation of chemical potential of graphene stimulated by external voltage. Later, in Figure 4b, we designed a switchable graphene-based metamaterial absorber using a single-layer continuous dumbbell-shaped graphene microstructure to achieve the narrow bandwidth and dual-band absorption [55]. The bandwidths of the two perfect absorption peaks are as narrow as 26.…”

Quasi-trapped modes in metasurfaces of anisotropic MoS$_2$ nanoparticles for absorption and polarization control in the telecom optical range

“…Note that due to inverse symmetry of the MoS 2 disk NP 47 there is no bianisotropy, but a nonlocal response can be excited. This result is a consequence of the anisotropy of NP material since for these irradiation conditions this effect is not observed in isotropic disks 47 for which the magnetic dipole component m z is determined only by the local term with α mm zz in (6). Formally, we can also include the nonlocal response in effective polarizabilities (which become dependent on irradiation conditions) defining them as…”

“…3 using gold mushrooms on a complex substrate, the quality factor is about 130 in the near-infrared range; in the theoretical work 4 for an array of gold nanoribbons on a thin gold layer, it reaches 350 in the visible range. In addition, the terahertz absorbers based on the structured graphene 6 with quality factor of about 9 and with quality factor of about several hundred units 7 for a wavelength 1550 nm were proposed. An additional remarkable feature of narrowband absorbers is high sensitivity to the local environment, which allows to detect individual particles and nanoobjects with high precision.…”

Deep Learning for the Design of Toroidal Metasurfaces

“…In 2010, the resonant excitation of TD in metamaterial had been first demonstrated [7]. Afterwards, TD metasurfaces have attracted the attention of many researchers and been applied to a variety of fields such as electromagnetically induced transparency, highly sensitive sensors, modulators and absorbers [8], [9], [10], [11], [12], [13].…”