A tunable ultra-broadband terahertz absorber based on two layers of graphene ribbons

Daraei, Omid Mohsen; Goudarzi, Kiyanoush; Bemani, Mohammad

doi:10.1016/j.optlastec.2019.105853

Cited by 23 publications

(12 citation statements)

References 27 publications

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“…Then, a hyperbolic metamaterial consisting of a multilayer structure of alternating graphene and Al 2 O 3 layers on a CaF2 substrate is realized and characterized in [12]. More recently, a tunable ultra-broadband THz absorber based on two layers of graphene ribbons and two different kinds of substrate materials is proposed in [13] while an extensive study on broadband near-perfect absorbers consisting of single-layered and non-structured graphene loaded with periodical arrays of dielectric bricks is presented in [14]. Finally, in [15] a reliable method to extract the electromagnetic constitutive tensors of complex synthesized multilayer graphene-dielectric stacks in the terahertz band is derived.…”

Section: Introductionmentioning

confidence: 99%

“…Nevertheless, the realization of periodic graphene nanostructures is still not an easy task. Recently, Salisbury absorber screens, consisting of a thin resistive film, a dielectric spacer and a backside reflector, have attracted growing interest for the realization of graphene-based THz absorbers [7,[13][14][15][16][17][18]. In fact, graphene films can act as resistive films [7] and, in addition, their conductivity can be tuned in order to obtain optimum absorption.…”

Section: Introductionmentioning

confidence: 99%

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Low-Terahertz Transparent Graphene-Based Absorber

2020

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A new, transparent, metal-free absorber, based on the use of multilayer graphene/dielectric laminates (GLs), is proposed for applications in the low-terahertz frequency range. The designed absorber has a total thickness of around 70 µm and consists of a front matching dielectric layer followed by a GL, a dielectric spacer and a back GL. The laminates are periodic structures constituted of graphene sheets separated by 50-nm-thick polyethylene terephthalate (PET) interlayers, while the matching layer and the spacer are one-quarter-wavelength thick and made of PET. The GLs are modeled as homogeneous-equivalent single layers (ESLs) characterized by their sheet resistances Rs. An innovative analytical method is proposed in order to select Rs values optimizing the electromagnetic wave absorption either in low-gigahertz or low-terahertz frequency range. The frequency spectra of the absorption, reflection and transmission coefficients are computed in the range up to 4 THz by using different values of Rs. Then, realistic Rs values of chemically doped graphene monolayers over PET substrates are considered. The designed absorbers are characterized by an absorption coefficient with a peak value of about 0.8 at the first resonant frequency of 1.1 THz, and a 1.4 THz bandwidth centered at 1.5 THz with reflection coefficient below - 10 dB. Moreover, the optical transmittance of the proposed absorbers are computed by means of the optical matrix theory and it is found to be greater than 86% in all the visible ranges.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Low-Terahertz Transparent Graphene-Based Absorber

2020

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“…The impedance matching theory gave a tunable THz ultra‐BMAs based on two layers of graphene ribbons. [ 219 ] The normalized bandwidth of 70% absorption can reach up to 118%. Impedance matching theory can perfectly explain why BMAs with different materials can achieve different absorption effects.…”

Section: Theoretical Foundations or Principles Of Broadband Metamater...mentioning

confidence: 99%

“…For example, it has been proposed to construct a BMA with two different dielectric layers separating two graphene bands on an Au sheet. [ 219 ] The fractional bandwidth can reach 118% due to the superposition of two absorption peaks when the change of E f of graphene can change the absorption. Moreover, a nine‐layer graphene/dielectric‐based BMA was given, [ 501 ] which is able to achieve absorption‐to‐reflection switching by electrical tuning.…”

Section: Tunable or Reconfigurable Broadband Metamaterials Absorbersmentioning

confidence: 99%

“…It possesses excellent electrical tunability, which provides many exciting possibilities for the THz and optical technology-related fields. BMAs based on graphene have been widely demonstrated with tunable features, [97][98][99]219,225,500,501] and the Fermi energy level of graphene could be varied with the applied bias voltages. On this basis, a tunable BMA based on a graphene-patterned resonant structure was designed and is shown in Figure 15a.…”

Section: Electrically Tunable Broadband Metamaterials Absorbersmentioning

confidence: 99%

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Review of Broadband Metamaterial Absorbers: From Principles, Design Strategies, and Tunable Properties to Functional Applications

Wang

Duan

et al. 2023

Adv Funct Materials

154

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Metamaterial absorbers have been widely studied and continuously concerned owing to their excellent resonance features of ultra-thin thickness, light-weight, and high absorbance. Their applications, however, are typically restricted by the intrinsic dispersion of materials and strong resonant features of patterned arrays (mainly referring to narrow absorption bandwidth). It is, therefore essential to reassert the principles of building broadband metamaterial absorbers (BMAs). Herein, the research progress of BMAs from principles, design strategies, tunable properties to functional applications are comprehensively and deeply summarized. Physical principles behind broadband absorption are briefly discussed, typical design strategies in realizing broadband absorption are further emphasized, such as top-down lithography, bottom-up self-assembly, and emerging 3D printing technology. Diversified active components choices, including optical response, temperature response, electrical response, magnetic response, mechanical response, and multi-parameter responses, are reviewed in achieving dynamically tuned broadband absorption. Following this, the achievements of various interdisciplinary applications for BMAs in energy-harvesting, photodetectors, radar-IR dual stealth, bolometers, noise absorbing, imaging, and fabric wearable are summarized. Finally, the challenges and perspectives for future development of BMAs are discussed.

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