A Broadband Graphene-Based THz Coupler with Wide-Range Tunable Power-Dividing Ratios

Wu, Yongle; Qu, Meijun; Liu, Yuanan; Ghassemlooy, Zabih

doi:10.1007/s11468-016-0409-9

Cited by 15 publications

(11 citation statements)

References 13 publications

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“…The surface conductivity, σ g , of graphene is supported by the Kubo optical surface conductivity formula, which, at room temperature, since the photon energy in the simulated mid-infrared wavelength range is always less than 2μ c [33], the intraband transition dominates the interband transition and, as a consequence, it can be explained in terms of the Drude model in the mid-infrared [24,25,29]:…”

Section: Theory and Numerical Methodsmentioning

confidence: 94%

“…Recently, a wide range of research has promoted the development of various types of graphene-based plasmonic devices, such as metasurfaces [14,15], optical waveguides [16,17], switches [18][19][20], modulators [21][22][23], filters [24,25], refractive index sensors [26,27], power splitters [16,28], multi/demultiplexers [29,30], metamaterials [31,32], and couplers [33,34]. Graphene ribbons support two kinds of SPP modes: the waveguide modes with the concentrated field along the entire area of the ribbon and the edge modes with the concentrated field on the verge of the ribbon [35,36].…”

Section: Introductionmentioning

confidence: 99%

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Tunable nano-scale graphene-based devices in mid-infrared wavelengths composed of cylindrical resonators

Asgari

Kashani

Granpayeh

2018

J. Opt.

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The performances of three optical devices including a refractive index sensor, a power splitter, and a 4-channel multi/demultiplexer based on graphene cylindrical resonators are proposed, analyzed, and simulated numerically by using the finite-difference time-domain method. The proposed sensor operates on the principle of the shift in resonance wavelength with a change in the refractive index of dielectric materials. The sensor sensitivity has been numerically derived. In addition, the performances of the power splitter and the multi/demultiplexer based on the variation of the resonance wavelengths of cylindrical resonator have been thoroughly investigated. The simulation results are in good agreement with the theoretical ones. Our studies demonstrate that the graphene based ultra-compact, nano-scale devices can be improved to be used as photonic integrated devices, optical switching, and logic gates.

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Section: Theory and Numerical Methodsmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

Tunable nano-scale graphene-based devices in mid-infrared wavelengths composed of cylindrical resonators

Asgari

Kashani

Granpayeh

2018

J. Opt.

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“…(where is the Fermi energy level) [49], and consequently the intra-band contribution dominates the inter-band contribution. As a result, simplifies to a Drude-like expression, that is, = 2 ∕ ℏ 2 ( + −1 ) [50], where , ℏ, are the electron charge, the reduced Planck constant and the relaxation time, respectively.…”

Section: Theory and Numerical Methods Of Simulationmentioning

confidence: 99%

“…1). It is worth indicating that the SPPs propagation constant supported by a graphene layer can be easily derived as [49]:…”

Section: Theory and Numerical Methods Of Simulationmentioning

confidence: 99%

Terahertz multi-plasmon induced reflection and transmission and sensor devices in a graphene-based coupled nanoribbons resonators

Noual

Amrani

Boudouti

et al. 2019

Optics Communications

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We demonstrate numerically multi-plasmon-induced reflection (PIR), multi-plasmon-induced transparency (PIT) and propose a highly sensitive refractive index nanosensor in a novel ultra-compact graphene-based nano-device, operating in the terahertz frequency range. The base structure of the system is composed out of a bus waveguide made out of graphene coupled to resonators inserted along or aside the waveguide where each resonator is constituted by a set of two coupled graphene nano-ribbons (CGNR). The latters behave as a molecule-like entity, whose surface plasmon eigen-modes originate from the splitting of the single ribbons modes. We show that the two CGNRs can also be regarded as an effective rectangular cavity-like system, so that the insertion of the latter along or aside the graphene bus waveguide (GBW) enables the design of tunable selective or rejective filters, respectively. By inserting two identical effective cavities in the structure, into a Λlike state (in analogy with three level atomic systems), we show the possibility of realizing multiple plasmon induced reflection, and highlight its fast light-features. On the other hand, if the two identical cavities are set symmetrically on each side of the GBW with slightly detuned Fermi energy levels in a V-like configuration, multi-plasmon induced transparency can be obtained. In addition, a highly sensitive refractive index nanosensor is showcased. The latter consists in a GBW, sidecoupled to an effective cavity-oscillator embedded with the analyte to be detected. The sensitivity of the sensor is numerically derived. Owing to its simple structure, the proposed sensor may offer the advantage of being easily fabricated. The showcased graphene-based devices proposed in this work should help the design of tunable and highly integrated optical devices such as nano-filters, optical switches and highly sensitive nanosensors.

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“…The special spectrum of the charge carriers leads to a number of interesting transport properties, which have been intensively studied in the literature [6,7]. Graphene has potential applications in optoelectronics [8][9][10][11][12][13]. It has renowned applications in the development of bioelectric sensory devices to measure glucose levels, hemoglobin levels, and cholesterol due to its high conductivity [14].…”

Section: Introductionmentioning

confidence: 99%

Electromagnetic Wave Reflectance, Transmittance, and Absorption in a Graphene-Covered Uniaxial Crystal Slab

Azam¹,

Toqeer²,

Ghaffar³

et al. 2018

PIER M

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A theoretical investigation of the interaction of electromagnetic plane waves with a uniaxial crystal slab bounded by two graphene layers from both sides placed in free space is presented in this paper. An 8×8 matrix method is developed using boundary conditions at a grapheneuniaxial anisotropic crystal interface and a uniaxial anisotropic crystal-graphene interface. The developed matrix is used to find reflection and transmission coefficients by Crammer's rule. Numerical results are presented to demonstrate the effect of frequency of the incident wave, thickness of the uniaxial crystal slab, and Fermi energy of the graphene on the reflected and transmitted energies. The presented formulations and results are confirmed by published results of some limited cases.

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A Broadband Graphene-Based THz Coupler with Wide-Range Tunable Power-Dividing Ratios

Cited by 15 publications

References 13 publications

Tunable nano-scale graphene-based devices in mid-infrared wavelengths composed of cylindrical resonators

Tunable nano-scale graphene-based devices in mid-infrared wavelengths composed of cylindrical resonators

Terahertz multi-plasmon induced reflection and transmission and sensor devices in a graphene-based coupled nanoribbons resonators

Electromagnetic Wave Reflectance, Transmittance, and Absorption in a Graphene-Covered Uniaxial Crystal Slab

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