One-dimensional multiband terahertz graphene photonic crystal filters

Li, Yizhe; Qi, Limei; Yu, Junsheng; Chen, Zhijiao; Yao, Yuan; Liu, Xiaoming

doi:10.1364/ome.7.001228

Cited by 69 publications

(28 citation statements)

References 31 publications

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“…We consider the multilayer stack as a uniaxial homogeneous medium, which has the optical axis perpendicular to the plane of interface, i.e., the x-y plane. Now, the wavenumbers corresponding to the TE-and TM-polarized waves propagating in the i th layer of the structure can be determined as 49 In these equations, k 0 is the free-space wavenumber,k iz is the wavenumber of the normal components, k ix = k 0 sin θ , and the subscripts t , ⊥ represent the transverse and normal (directions) permittivity values, respectively.…”

Section: Design and Analysismentioning

confidence: 99%

Tunable absorber embedded with GST mediums and trilayer graphene strip microheaters

Pourmand

Choudhury

Mohamed

2021

Sci Rep

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Investigation was made of the optical response of metal-dielectric stacks-based cavity structures embedded with graphene microheaters for the purpose of perfect absorption. The absorber configuration exploits the Ge2Sb2Te5 (GST) phase changing medium, and the effects of different parametric and operational conditions on the absorption spectra were explored. The refractive indices of GST layers can be manipulated by the external electrical pulses applied to microheaters. The amplitude and duration of electrical pulses define the crystallinity ratio of the used GST mediums. The results revealed achieving perfect absorption (> 99%) in the visible and infrared (IR) regimes of the electromagnetic spectrum upon incorporating two thin GST layers of different thicknesses (in the stack) in the amorphous state. The proposed configuration showed the capability of introducing independent transition state (amorphous and/or crystalline) for each GST layer—the visible regime could be extended to the IR regime, and the perfect absorption peak in the IR regime could be broadened and red-shifted. It is expected that the structure would find potential applications in active photonic devices, infrared imaging, detectors and tunable absorbers.

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Section: Design and Analysismentioning

confidence: 99%

Tunable absorber embedded with GST mediums and trilayer graphene strip microheaters

Pourmand

Choudhury

Mohamed

2021

Sci Rep

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“…To study the propagation of electromagnetic waves through the proposed structure, varieties of methods have been employed. These include the theory of plane wave expansion [64], finite difference time/frequency domain [65], TMM [66,67] and Green function method [16,17]. Among these, the TMM has been exploited in most of the investigations owing to its simplicity and flexibility.…”

Section: Analytical Treatmentmentioning

confidence: 99%

Wideband THz Filtering by Graphene-Over-Dielectric Periodic Structures With and Without MgF₂ Defect Layer

Pourmand

Choudhury

2020

IEEE Access

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Investigation of the spectral response of graphene-dielectric (SiO 2 )-based periodic structure was made in the far-infrared (IR) to the mid-IR frequency range, and the effects of different parametric and operational conditions on the transmission characteristics were explored. The presence of stop-bands, followed by Bragg reflection harmonics, in the low-frequency regime was observed exploiting the bilayer graphene (BLG) sheets. The width of stop-bands could be tuned by altering the number of periods as well as the chemical potential of BLG. The formation of a stop-band (with a transmission dip positioned at ~16 THz) having a span of ~3 THz was noticed, which is possibly a very large stop-bandwidth reported so far. The structure was also analyzed upon introducing a defect layer of MgF 2 having a thickness smaller than the dielectric medium. This results in shifting the position of stop-bands of the structure. The characteristics of transmission spectra were found to be greatly depending on the chemical potential (of BLG) and other operating conditionsthe feature that triggers the usefulness of the proposed structure in the design of optical modulators, tunable narrow-band filters and broad-band reflectors.

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“…In this equation, ν f is the Fermi velocity, ε r defines the relative permittivity of the dielectric slab, ε 0 is the permittivity of the free space, and d presents the thickness of the dielectric layer. For a uniaxial graphene stripe in the x-y plane, the main diagonal elements of the permittivity tensor are non-zero and given by [21]. By taking into consideration the fact that the normal electric field cannot excite any current in the 2D graphene sheet, the normal component of the permittivity can be regarded as ε G,⊥ = 1 [12,25].…”

Section: Materials and Physical Structuresmentioning

confidence: 99%

Terahertz tunable photonic crystal optical filter containing graphene and nonlinear electro-optic polymer

2019

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In this paper, new photonic crystal optical filters with very unique optical characteristics are presented. The designed structures are composed of stacked SiO 2 isotropic dielectric slabs separated by monolayer graphene sheets. Defect layers of nonlinear electro-optical polymer materials are also inserted to behave as the resonant areas. Results obtained by using the transfer matrix method approach clearly reflect the possibility of the wide photonic band gap generation in the absorption spectra of the proposed crystals in the terahertz frequency range. Furthermore, a very strong relation is seen between the defect layer(s) induced resonant modes and the location/number of the defect(s) inside the crystal. To widen the scope of our findings, in addition to studying the dependencies on the structural characteristics, the tunability of the optical features using the external parameters is investigated systematically. It is shown that the number and central frequencies of the resonant modes are controllable in the far-infrared range by adjusting the temperature and wave incident angle. Thus, the proposed crystals might have remarkable applications in the fabrication of multi-channel tunable filters used in optical integrated circuits.

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One-dimensional multiband terahertz graphene photonic crystal filters

Cited by 69 publications

References 31 publications

Tunable absorber embedded with GST mediums and trilayer graphene strip microheaters

Tunable absorber embedded with GST mediums and trilayer graphene strip microheaters

Wideband THz Filtering by Graphene-Over-Dielectric Periodic Structures With and Without MgF₂ Defect Layer

Terahertz tunable photonic crystal optical filter containing graphene and nonlinear electro-optic polymer

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One-dimensional multiband terahertz graphene photonic crystal filters

Cited by 69 publications

References 31 publications

Tunable absorber embedded with GST mediums and trilayer graphene strip microheaters

Tunable absorber embedded with GST mediums and trilayer graphene strip microheaters

Wideband THz Filtering by Graphene-Over-Dielectric Periodic Structures With and Without MgF2 Defect Layer

Terahertz tunable photonic crystal optical filter containing graphene and nonlinear electro-optic polymer

Contact Info

Product

Resources

About

Wideband THz Filtering by Graphene-Over-Dielectric Periodic Structures With and Without MgF₂ Defect Layer