Independently tunable electromagnetically induced transparency effect and dispersion in a multi-band terahertz metamaterial

Sarkar, Rakesh; Ghindani, Dipa; Devi, Koijam Monika; Prabhu, S. S.; Ahmad, Amir; Kumar, Gagan

doi:10.1038/s41598-019-54414-5

Cited by 72 publications

(29 citation statements)

References 56 publications

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“…Numerical simulations were done using the finite element method (FEM) in the frequency domain solver of CST 2018 4 , 42 . The boundary conditions and the mesh type are considered the same as in Ref.…”

Section: Resultsmentioning

confidence: 99%

Graphene-based dual-functional chiral metamirror composed of complementary 90° rotated U-shaped resonator arrays and its equivalent circuit model

Asgari

Fabritius

2021

Sci Rep

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An equivalent circuit model (ECM) using a MATLAB code to analyze a tunable two-layered graphene-based chiral dual-function metamirror, is proposed in this work. The investigated metastructure is composed of complementary U-shaped graphene resonator arrays in the terahertz (THz) region. The ECM analysis could be used for any two-layered chiral metastructure for any frequencies, containing resonators with a thickness less than λ/50. The characteristics of the proposed tunable metamirror were analyzed numerically using the finite element method (FEM) in CST Software to verify the ECM analysis. The proposed metamirror can be used in polarization-sensitive devices in the THz region with simpler biasing without a need for ion gels or similar. It works as a broadband TE and multiband (four bands) TM mirror in the 0.3–4.5 THz bandwidth with a strong linear dichroism (LD) response (up to 96%). The designed mirror is a dynamically tunable, dual-functional structure, requiring only 90° rotation of the incident electromagnetic fields to switch between broadband and multiband spectral behavior making it a promising candidate for future THz intelligent systems. The proposed ECM is in agreement with the FEM results. The ECM analysis provides a simple, fast, and effective way to understand the metamirror’s behavior and guides for the design and analysis of graphene-based chiral metastructures in the THz region.

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Section: Resultsmentioning

confidence: 99%

Graphene-based dual-functional chiral metamirror composed of complementary 90° rotated U-shaped resonator arrays and its equivalent circuit model

Asgari

Fabritius

2021

Sci Rep

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“…Well defined theoretical models have added strength to the experimental findings ( Gu et al., 2012 ; Tassin et al., 2009 ). Dual band EIT, polarization independent EIT phenomenon, and slow light effect have been given considerable attention in recent years ( Sarkar et al., 2019 , 2020 ). EIT based MMs and their applications have seen increasing interest among the research community.…”

Section: Electromagnetically Induced Transparencymentioning

confidence: 99%

Toroidal electromagnetically induced transparency based meta-surfaces and its applications

2022

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Summary The vigorous research on low-loss photonic devices has brought significance to a new kind of electromagnetic excitation, known as toroidal resonances. Toroidal excitation, possessing high-quality factor and narrow linewidth of the resonances, has found profound applications in metamaterial (MM) devices. By the coupling of toroidal dipolar resonance to traditional electric/magnetic resonances, a metamaterial analogue of electromagnetically induced transparency effect (EIT) has been developed. Toroidal induced EIT has demonstrated intriguing properties including steep linear dispersion in transparency windows, often leading to elevated group refractive index in the material. This review summarizes the brief history and properties of the toroidal resonance, its identification in metamaterials, and their applications. Further, numerous theoretical and experimental demonstrations of single and multiband EIT effects in toroidal-dipole-based metamaterials and its applications are discussed. The study of toroidal-based EIT has numerous potential applications in the development of biomolecular sensing, slow light systems, switches, and refractive index sensing.

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“…Compared to bright modes, which would naturally couple with free space electromagnetic fields, dark modes are excited by near-field coupling with the bright modes, exhibiting a narrower absorption [33] . Importantly, the plasmonic split-ring resonators (SRRs), closed-ring resonators (CRRs), and cut wire (CW) resonators are several meta-atom building blocks that can support bright modes and dark modes [34][35][36] .…”

Section: Introductionmentioning

confidence: 99%

Ultrafast all-optical switching of dual-band plasmon-induced transparency in terahertz metamaterials

et al. 2022

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An active ultrafast formation and modulation of dual-band plasmon-induced transparency (PIT) effect is theoretically and experimentally studied in a novel metaphotonic device operating in the terahertz regime, for the first time, to the best of our knowledge. Specifically, we designed and fabricated a triatomic metamaterial hybridized with silicon islands following a newly proposed modulating mechanism. In this mechanism, a localized surface plasmon resonance is induced by the broken symmetry of a C 2 structure, acting as the quasi-dark mode. Excited by exterior laser pumps, the photo-induced carriers in silicon promote the quasi-dark mode, which shields the near-field coupling between the dark mode and bright mode supported by the triatomic metamaterial, leading to the dynamical modulation of terahertz waves from individual-band into dual-band PIT effects, with a decay constant of 493 ps. Moreover, a remarkable slow light effect occurs in the modulating process, accompanied by the dual-transparent windows. The dynamical switching technique of the dual-band PIT effect introduced in this work highlights the potential usefulness of this metaphotonic device in optical information processing and communication, including multi-frequency filtering, tunable sensors, and optical storage.

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Independently tunable electromagnetically induced transparency effect and dispersion in a multi-band terahertz metamaterial

Cited by 72 publications

References 56 publications

Graphene-based dual-functional chiral metamirror composed of complementary 90° rotated U-shaped resonator arrays and its equivalent circuit model

Graphene-based dual-functional chiral metamirror composed of complementary 90° rotated U-shaped resonator arrays and its equivalent circuit model

Toroidal electromagnetically induced transparency based meta-surfaces and its applications

Ultrafast all-optical switching of dual-band plasmon-induced transparency in terahertz metamaterials

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