Tunable ultra-wideband terahertz absorber based on graphene disks and ribbons

Biabanifard, Sadegh; Biabanifard, Mohammad; Asgari, Somayyeh; Asadi, Shahrouz; Yagoub, M.C.E.

doi:10.1016/j.optcom.2018.07.008

Cited by 126 publications

(52 citation statements)

References 39 publications

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“…where Z d = Z 0 /n p represents the impedance of the dielectric substance, and β d is the propagation constant of propagating THz wave in the dielectric material. Z g1 and Z g2 are the impedance of the PAGDs, whose resistance, inductance, and capacitance of the nth mode are calculated as follows 29,[36][37][38] :…”

Section: Circuit Modelmentioning

confidence: 99%

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

Aghaee

Orouji

2019

Int J Numerical Modelling

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The realization of broadband absorption in the terahertz spectra is of significant interest in advanced terahertz applications. In this work, a novel ultrabroadband absorber based on the periodic array of graphene disks and graphene continues sheet is proposed. A developed transmission line theory besides the analytical circuit model of graphene disks and graphene continues sheet are exploited to describe the absorber structure by its circuit model. By using three graphene layers and considering impedance matching concept, the normalized bandwidth of 90% absorption is extended up to 121% of the central frequency. Also, the dependence of the absorption spectra on the structure parameters is investigated and analyzed. Moreover, the performance of the device under possible fabrication errors is discussed. In pursuit of evaluating the efficiency, accuracy, and validity of the proposed method, full-wave numerical modeling is performed by the finite element method. The results show that the proposed circuit approach, in addition to having advantages in terms of computing time and the need for memory resource, is in a good agreement with the full-wave simulations. Furthermore, the structure of the absorber is relatively simple, and it can be manufactured by chemical vapor deposition techniques.

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Section: Circuit Modelmentioning

confidence: 99%

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

Aghaee

Orouji

2019

Int J Numerical Modelling

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“…The conductivity of the two graphene layers can be controlled separately at a time by applying two different gate voltages V g1 and V g2 in between the graphene layers and the bottom gating gold structure to exploit T μ and B μ , respectively. 49 The additional two components yield no effect on the absorption characteristics as there is no transmission from the backside of the primarily designed proposed graphene-based absorber design as seen from Figure 3C. The continuous bottom layer of graphene acts as a reflector in a particular frequency-band in the terahertz (THz) region by changing the chemical properties of the graphene.…”

Section: Simulated Results and Discussionmentioning

confidence: 99%

Graphene based metasurface with near unity broadband absorption in the terahertz gap

Ghosh

Das

Bhattacharyya

2020

Int J RF Microw Comput Aided Eng

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This paper reports a novel graphene metasurface exhibiting near-unity absorption over a wide bandwidth of 9.74 THz ranging from 2.06 to 11.80 THz with a fractional bandwidth of 140.86% with respect to the center frequency of 6.93 THz within the terahertz gap of the electromagnetic spectrum. The proposed structure consists of two layers of graphene separated by silicon dioxide (SiO 2). On the top of SiO 2 , a modified fractal-shaped 1 nm thick graphene pattern is deposited while a square-shaped graphene pattern of identical thickness completely covers the backside of the SiO 2 substrate. The absorber was found to be polarization independent under the normal incidence of the approaching electromagnetic wave (EM) toward the top layer of the structure due to its 4-fold structural symmetry. The designed structure offers stable absorption up to 60 incident angle under TE polarization and 40 incident angle under TM polarization. The structure is~λ/55.9 thin and maintains periodicity of~λ/21.7; thereby validating the effective homogeneity condition in the sub-wavelength domain. This graphene-based absorber can find several applications including, sensors, detectors, spatial light modulators, and in spectroscopic detectors, and so forth, in the "Terahertz Gap" for next-generation 5G communication system and beyond.

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“…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].…”

Section: Reconfigurability Of Graphene Metasurface Absorbersmentioning

confidence: 99%

Implementation of Atomically Thick Graphene and Its Derivatives in Electromagnetic Absorbers

Tian

Shi

et al. 2019

Applied Sciences

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To reduce the radar cross section at microwave frequencies, it is necessary to implement electromagnetic (EM) absorbing devices/materials to decrease the strength of reflected waves. In addition, EM absorbers also find their applications at higher spectrum such as THz and optical frequencies. As an atomic-thick two-dimensional (2D) material, graphene has been widely used in the development of EM devices. The conductivity of graphene can be electrostatically or chemically tuned from microwave to optical light frequencies, enabling the design of reconfigurable graphene EM absorbers. Meanwhile, the derivatives of graphene such as reduced graphene oxide (rGO) also demonstrate excellent wave absorbing properties when mixed with other materials. In this article, the research progress of graphene and its derivatives based EM absorbers are introduced and the future development of graphene EM absorbing devices are also discussed.

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Tunable ultra-wideband terahertz absorber based on graphene disks and ribbons

Cited by 126 publications

References 39 publications

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

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

Graphene based metasurface with near unity broadband absorption in the terahertz gap

Implementation of Atomically Thick Graphene and Its Derivatives in Electromagnetic Absorbers

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