Graphene and metal hybridized terahertz metasurfaces toward tunable plasmon-induced transparency effects

Krishna, K.N. Indu; Devi, Koijam Monika; Chowdhury, Dibakar Roy

doi:10.1016/j.cap.2022.04.011

Cited by 15 publications

(5 citation statements)

References 42 publications

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“…and other geometries [36,37]. These structures operate predominantly on the principles of surface and cavity plasmon resonances inherent to graphene micro absorbers.…”

Section: Introductionmentioning

confidence: 99%

Enhancing broadband terahertz absorption via a graphene-based metasurface absorber featuring a rectangular ring and triple crossbars

Chou Chau

2024

Phys. Scr.

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This study introduces an innovative strategy to achieve a versatile and adaptive terahertz (THz) absorber by leveraging a graphene-based metasurface. This metasurface comprises a rectangular ring and three crossbars, combined with a grounded gold film, all separated by a thin SiO2 layer. The phenomenon of plasmonic hybridization, involving surface and cavity plasmon resonances, enables the interaction between incident THz waves and the proposed graphene-based metasurface, leading to a substantial enhancement in the absorptance bandwidth of the plasmonic system. The enhancement of absorptance can be finely adjusted by modifying the chemical potential (Fermi energy) in graphene and manipulating the structural parameters of the device. A notable feature of our design is its inherent resistance to variations in incident angles and polarization states of incoming electromagnetic waves. The proposed device achieves an absorptance exceeding 80% across a continuous spectrum, exhibiting a bandwidth of approximately 0.90 THz spanning from 0.94 to 1.84 THz. This robust characteristic ensures consistent and reliable performance in diverse scenarios. Our findings present intriguing prospects for various applications centered on wave modulation, which encompass, but are not limited to, THz imaging, filtering, energy harvesting, and tunable sensors.

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“…and other geometries [36,37]. These structures operate predominantly on the principles of surface and cavity plasmon resonances inherent to graphene micro absorbers.…”

Section: Introductionmentioning

confidence: 99%

Enhancing broadband terahertz absorption via a graphene-based metasurface absorber featuring a rectangular ring and triple crossbars

Chou Chau

2024

Phys. Scr.

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“…In general, bright mode has a broad transmission spectrum with a low Q-factor. Based on the bright-dark coupling mode and bright-bright coupling mode, EIT effect with different characteristics, such as polarization-insensitive, 16 tunable, 17 low loss, 18 and multi-band, 19 are proposed. Over the past decade, the development of active metasurface ranges from microwave band to visible band.…”

Section: Introductionmentioning

confidence: 99%

High-transmission and large group delay terahertz triple-band electromagnetically induced transparency in a metal-perovskite hybrid metasurface

Chen

Yang

2023

Phys. Chem. Chem. Phys.

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“…Such an unparalleled control of electromagnetic fields can be achieved by simply tuning the geometry of the unit cells or meta-atoms that constructs the periodic array of the meta-device [7,8], The emergence and evolution of metamaterials have gained momentum after the seminal works on realizing negative index media came into picture about two decades ago [9,10]. Since then, these artificial photonic structures have seen a wide range of applications in realizing Electromagnetically induced transparency (EIT) [11,12], near-unity absorbers [13,14], sensors [15][16][17][18], switches [19][20][21][22], as well as extensive implementations in the studies pertaining to nonlinear-optics [23,24], quantum computation [25], observation of exceptional points [26], extraordinary transmissions [27,28] and many more. In this regard, we would like to mention that EIT-like effects are analogous to quantum-interference effects that lead to the observation of high transmission window in an otherwise absorptive background.…”

Section: Introductionmentioning

confidence: 99%

Accessing dual toroidal modes in terahertz plasmonic metasurfaces through polarization-sensitive resonance hybridization

et al. 2023

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Plasmonic metasurfaces have been quite a fascinating framework to invoke transformation of incident electromagnetic waves in recent times. Oftentimes, the building block of these metasurfaces (unit cells) consists of two or more meta-resonators. As a consequence, near-field coupling amongst these constituents may occur depending upon the spatial and spectral separation of the individual elements (meta-resonators). In such coupled structures resonance mode-hybridization can help in explaining the formation and energy re-distribution among the resonance modes. However, the coupling of these plasmonic modes is extremely sensitive to incident probe beam polarization and offers ample scope to harness newer physics. A qualitative understanding of the same can be attained through mode-hybridization phenomena. In this context, here, we have proposed a multi-element metastructure unit cell consisting of split ring and dipole resonators aiming to explore the intricate effects of the polarization dependency of these hybridized modes. Therefore, multi-resonator systems with varied inter-resonator spacings (sp= 3.0, 5.0 and 7.0 μm) are fabricated and characterized in the terahertz domain, showing a decrement in the frequency detuning (δ) by 30% (approx.) for a particular polarization orientation of THz probe beam. However, no such detuning is observed for the other polarization. Further, as an outcome of the strong near-field coupling, the emergence of dual toroidal modes is observed. Excitation of toroidal modes demands thoughtful mode engineering to amplify the response of these otherwise feeble modes. Such modes are capable of strongly confining electromagnetic fields due to higher Quality (Q-) factor. Our experimental studies have shown significant signature of the presence of these modes in the Terahertz (THz) domain, backed up with rigorous numerical investigations along with multipole analysis. The calculated multipole decomposition demonstrates stronger scattering amplitude enhancements (~ 7 times) at both the toroidal modes compared to off-resonant values. Such dual toroidal resonances are capable of superior field confinements as compared to single toroidal mode, and therefore, can potentially serve as an ideal testbed in developing next-generation multi-mode bio-sensors as well as realization of high Q-factor lasing cavities, electromagnetically induced transparency (EIT), non-radiating anapole modes, novel ultrafast switching, and several other applications.

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Graphene and metal hybridized terahertz metasurfaces toward tunable plasmon-induced transparency effects

Cited by 15 publications

References 42 publications

Enhancing broadband terahertz absorption via a graphene-based metasurface absorber featuring a rectangular ring and triple crossbars

Enhancing broadband terahertz absorption via a graphene-based metasurface absorber featuring a rectangular ring and triple crossbars

High-transmission and large group delay terahertz triple-band electromagnetically induced transparency in a metal-perovskite hybrid metasurface

Accessing dual toroidal modes in terahertz plasmonic metasurfaces through polarization-sensitive resonance hybridization

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