An electrically tunable plasmonic optical modulator with high modulation depth based on graphene-wrapped silver nanowire

Zhang, C; Tu, Luqi; Huang, Zhenhua; Liu, L; Zhan, Peng; Sun, Cunzhi; Wang, Z

doi:10.1088/2040-8978/18/12/125007

Cited by 10 publications

(4 citation statements)

References 38 publications

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“…The fabrication feasibility of such structures via chemical-vapor-deposition growth of monolayer graphene [56,57] or draping graphene flakes over wires with an adhesive tape [18] has been demonstrated. Furthermore, they have been exploited for various applications such as tuning the absorption [58], cloaking [59,60], waveguiding [61][62][63] and nonlinear harmonic generation [64].…”

Section: Time Modulated Metasurface a Implementation Based On Graphen...mentioning

confidence: 99%

Electrically tunable harmonics in time-modulated metasurfaces for wavefront engineering

2018

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Modulation of metasurfaces in time gives rise to several exotic space-time scattering phenomena by breaking the reciprocity constraint and generation of higher-order frequency harmonics. We introduce a new design paradigm for time-modulated metasurfaces, enabling tunable engineering of the generated frequency harmonics and their emerging wavefronts by electrically controlling the phase delay in modulation. It is demonstrated that the light acquires a dispersionless phase shift regardless of incident angle and polarization, upon undergoing frequency conversion in a timemodulated metasurface which is linearly proportional to the modulation phase delay and the order of generated frequency harmonic. The conversion efficiency to the frequency harmonics is independent of modulation phase delay and only depends on the modulation depth and resonant characteristics of the metasurface, with the highest efficiency occurring in the vicinity of resonance, and decreasing away from the resonant regime. The modulation-induced phase shift allows for creating tunable spatially varying phase discontinuities with 2π span in the wavefronts of generated frequency harmonics for a wide range of frequencies and incident angles. Specifically, we apply this approach to a time-modulated metasurface in the Teraherz regime consisted of graphene-wrapped silicon microwires. For this purpose, we use an accurate and efficient semi-analytical framework based on multipole scattering. We demonstrate the utility of the design rule for tunable beam steering and focusing of generated frequency harmonics giving rise to several intriguing effects such as spatial decomposition of harmonics, anomalous bending with full coverage of angles and dual-polarity lensing. Furthermore, we investigate the angular and spectral performance of the time-modulated metasurface in manipulation of generated frequency harmonics to verify its constant phase response versus incident wavelength and angle. The nonreciprocal response of the metasurface in wavefront engineering is also studied by establishing nonreciprocal links with large isolations via modulationinduced phase shift. The proposed design approach enables a new class of high-efficiency tunable metasurfaces with wide angular and frequency bandwidth, wavefront engineering capabilities, nonreciprocal response and multi-functionality.

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Section: Time Modulated Metasurface a Implementation Based On Graphen...mentioning

confidence: 99%

Electrically tunable harmonics in time-modulated metasurfaces for wavefront engineering

2018

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“…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%

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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“…Accordingly, the enhancement of this otherwise weak light-graphene interaction is one of the most important issues for its further applications in nanophotonics devices. Recently, various strategies to enhance absorption of graphene have been proposed, such as by constructing photonic cavities with strong localized optical density of state [19] and by wrapping the graphene over a metallic or dielectric bus-waveguide [20,21]. Besides, there have been recent efforts in improving the optical absorption by utilizing the intrinsic plasmonic resonances of nanostructured graphene, and even the near-unity absorption has been proposed by elaborately designing the nanostructured graphene resonator at the critical coupling condition, which actually could be easily tuned spectrally by changing the sizes and geometries of graphene [22,23].…”

mentioning

confidence: 99%

Broadband near-unity light absorption with anti-hermitian coupled stacked graphene metasurfaces

Yang¹,

Hu²,

Huang³

et al. 2020

Phys. Scr.

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Enhancement of the interaction between monolayer or few-layers graphene and light is crucial to the potential applications of graphene-based optoelectronic devices. Recently, various nanostructured graphene has been proposed to achieve efficient optical absorption, whereas the bandwidth of the enhanced spectral absorption is always fairly narrow, which might be disadvantageous to their opt-electrical applications relying on light harvesting. In this work, we propose an effective method of constructing a stacked graphene-based metasurface to achieve broadband unity absorption. The main concept of the design is to realize the near-zero mutual coupling among graphene resonators based on the idea of anti-Hermitian coupling. This coupling will restrain the mode splitting due to the effect of direct near-field coupling between the neighboring graphene resonators, and thus facilitate the realization of a broadband absorption through the superposition of the individual resonance. In principle, the absorption bandwidth could be expanded further, and the proposed idea might also be used to design broadband absorber of other sub-wavelength nano-resonators.

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An electrically tunable plasmonic optical modulator with high modulation depth based on graphene-wrapped silver nanowire

Cited by 10 publications

References 38 publications

Electrically tunable harmonics in time-modulated metasurfaces for wavefront engineering

Electrically tunable harmonics in time-modulated metasurfaces for wavefront engineering

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

Broadband near-unity light absorption with anti-hermitian coupled stacked graphene metasurfaces

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