Graphene Micro- and Nano-Plasmonics

Nene, Parinita; Strait, Jared H.; Chan, Weimin; Manolatou, Christina; Tiwari, Sandip; Rana, Farhan; Kevek, Joshua W.; McEuen, Paul L.

doi:10.1364/cleo_qels.2013.qth1b.2

“…In the contacted graphene, the metal regions act as capacitive reservoir for charge accumulation, and the graphene serves as an inductive channel, thus forming a resonant circuit that interacts strongly with the incident radiation. This is in striking contrast to the isolated ribbon case, where the coupling to incident radiation is weaker, and does not depend sensitively on the grating period [3,4,12]. The extension of the spatial mode also explains the significant reduction of plasmon frequency (predicted by the theory in Supplementary Section SS1 for the case Λ w) which is reduced by about a factor of √ 3 compared to that of an isolated graphene ribbon [11].…”

mentioning

confidence: 78%

“…However, when the metal contacts are made much wider than the graphene channel, a strong resonance emerges, characterized by high absorption in the graphene ribbon, at a resonant frequency that scales with n 1/4 w −1/2 , similar to the plasmon resonances in uncontacted graphene ribbons [3,12]. The surrounding material is assumed to be a uniform dielectric, in which case, the maximum achievable absorption in a thin-film (metal-graphene grating)…”

Section: Introductionmentioning

confidence: 99%

“…The mobility and carrier density (electron or hole) were taken to be µ = 1000 cm 2 V −1 s −1 and n = 1.5 × 10 13 cm −2 , respectively. The array shows no discernable plasmon resonance when the period Λ and graphene width w are comparable, giving instead a Drude-like response.However, when the metal contacts are made much wider than the graphene channel, a strong resonance emerges, characterized by high absorption in the graphene ribbon, at a resonant frequency that scales with n 1/4 w −1/2 , similar to the plasmon resonances in uncontacted graphene ribbons [3,12]. The surrounding material is assumed to be a uniform dielectric, in which case, the maximum achievable absorption in a thin-film (metal-graphene grating)…”

mentioning

confidence: 99%

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Tunable Terahertz Hybrid Metal–Graphene Plasmons

Jadidi

¹

,

Sushkov

²

,

Myers-Ward

³

et al. 2015

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Among its many outstanding properties, graphene supports terahertz surface plasma wavessub-wavelength charge density oscillations connected with electromagnetic fields that are tightly localized near the surface [1, 2]. When these waves are confined to finite-sized graphene, plasmon resonances emerge that are characterized by alternating charge accumulation at the opposing edges of the graphene. The resonant frequency of such a structure depends on both the size and the surface charge density, and can be electrically tuned throughout the terahertz range by applying a gate voltage [3,4]. The promise of tunable graphene THz plasmonics has yet to be fulfilled, however, because most proposed optoelectronic devices including detectors, filters, and modulators [5][6][7][8][9][10] desire near total modulation of the absorption or transmission, and require electrical contacts to the graphene -constraints that are difficult to meet using existing plasmonic structures. We report here a new class of plasmon resonance that occurs in a hybrid graphene-metal structure.The sub-wavelength metal contacts form a capacitive grid for accumulating charge, while the narrow interleaved graphene channels, to first order, serves as a tunable inductive medium, thereby forming a structure that is resonantly-matched to an incident terahertz wave. We experimentally demonstrate resonant absorption near the theoretical maximum in readily-available, large-area graphene, ideal for THz detectors and tunable absorbers. We further predict that the use of high mobility graphene will allow resonant THz transmission near 100%, realizing a tunable THz filter or modulator. The structure is strongly coupled to incident THz radiation, and solves a fundamental problem of how to incorporate a tunable plasmonic channel into a device with electrical contacts. In order to be applied in practical optoelectronic devices, graphene terahertz plasmonic resonators must be connected to an antenna, transmission line, metamaterial, or other electrical contact, in order to sense or apply a voltage or current, or to improve the coupling to free-space radiation. The conductive boundary screens the electric field and inhibits the accumulation of charge density at the opposing edges of the graphene channel, thus disrupting the traditional graphene plasmon mode. Until now, there was no experimental evidence that two-dimensional plasmons could be confined with conductive boundaries.In this letter, we demonstrate a new type of plasmon resonance in metal-contacted graphene, and we use analytic calculations, numerical simulations, and THz reflection and transmission measurements to confirm the principle of operation. These plasmon modes shows strong coupling to incident terahertz radiation, so that maximal absorption in graphene can be achieved at a resonance frequency that is gate-tunable. We also introduce an equivalent circuit model that predicts the resonant frequency, linewidth, and impedance matching condition of the fundamental plasmon mode, and can be used for d...

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“…Plasmonic resonances occur at mid-infrared and terahertz frequencies for typical carrier densities (several 10 12 cm -2 ) of graphene as opposed to visible or near-infrared excitations of traditional metallic plasmonic structures. As a result of these favorable properties, graphene plasmons covering mid-to far-IR frequency ranges have been extensively used in theoretical and experimental studies [13][14][15][16][17][18][19][20][21][22][23][24]. In addition, several device applications have been reported, including optoelectronic devices [14], ultrafast transistor based photodetectors [25][26][27], optical modulators [28,29], light emitters [30,31] transparent solar cells [32], and biosensors [33,34].…”

Section: Introductionmentioning

confidence: 99%

Multi-Band Plasmonic Platform Utilizing UT-Shaped Graphene Antenna Arrays

Ekşioğlu

¹

,

Çetin

²

,

Durmaz

³

2017

Plasmonics

6

0

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In this work, we introduce a plasmonic platform based on UT-shaped graphene antenna arrays. The proposed multi-resonant platform shows three different resonances, which can be independently tuned. The physical origin of these modes is shown with FDTD near-field distribution analyses, which are used to statically tune each resonance wavelength via the geometrical parameters, corresponding to different nearfield localization. We achieve statistical tuning of multiple resonances also by changing the number of graphene layers. Another static tuning of the optical response of the UT-shaped graphene antenna is achieved via the chemical potential and the relaxation time.

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“…However, when the metal contacts are made much wider than the graphene channel, a strong resonance emerges, characterized by high absorption in the graphene ribbon, at a resonant frequency that scales with n 1/4 w −1/2 , similar to the plasmon resonances in uncontacted graphene ribbons [3,12]. The surrounding material is assumed to be a uniform dielectric, in which case, the maximum achievable absorption in a thin-film (metal-graphene grating) is 50% [13] (also S26 in Supplementary Section).…”

mentioning

confidence: 96%

Hybrid Metal-Graphene Plasmons for Tunable Terahertz Technology

Jadidi,

Sushkov,

Myers-Ward

et al. 2015

Preprint

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Among its many outstanding properties, graphene supports terahertz surface plasma wavessub-wavelength charge density oscillations connected with electromagnetic fields that are tightly localized near the surface [1,2]. When these waves are confined to finite-sized graphene, plasmon resonances emerge that are characterized by alternating charge accumulation at the opposing edges of the graphene. The resonant frequency of such a structure depends on both the size and the surface charge density, and can be electrically tuned throughout the terahertz range by applying a gate voltage [3,4]. The promise of tunable graphene THz plasmonics has yet to be fulfilled, however, because most proposed optoelectronic devices including detectors, filters, and modulators [5-10] desire near total modulation of the absorption or transmission, and require electrical contacts to the graphene -constraints that are difficult to meet using existing plasmonic structures. We report here a new class of plasmon resonance that occurs in a hybrid graphene-metal structure.The sub-wavelength metal contacts form a capacitive grid for accumulating charge, while the narrow interleaved graphene channels, to first order, serves as a tunable inductive medium, thereby forming a structure that is resonantly-matched to an incident terahertz wave. We experimentally demonstrate resonant absorption near the theoretical maximum in readily-available, large-area graphene, ideal for THz detectors and tunable absorbers. We further predict that the use of high mobility graphene will allow resonant THz transmission near 100%, realizing a tunable THz filter or modulator. The structure is strongly coupled to incident THz radiation, and solves a fundamental problem of how to incorporate a tunable plasmonic channel into a device with electrical contacts.

show abstract

Graphene Micro- and Nano-Plasmonics

Cited by 3 publications

References 5 publications

Tunable Terahertz Hybrid Metal–Graphene Plasmons

Tunable Terahertz Hybrid Metal–Graphene Plasmons

Multi-Band Plasmonic Platform Utilizing UT-Shaped Graphene Antenna Arrays

Hybrid Metal-Graphene Plasmons for Tunable Terahertz Technology

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