Graphene plasmonics for tunable terahertz metamaterials

Ju, Long; Geng, Baisong; Horng, Jason; Girit, Çaǧlar; Martin, Michael; Hao, Zhao; Bechtel, Hans A.; Liang, Xiaogan; Zettl, A.; Shen, Y. R.; Wang, Feng

doi:10.1038/nnano.2011.146

Cited by 2,755 publications

(2,362 citation statements)

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“…Second, intraband transitions dominate in the terahertz range, resulting in an optical conductivity well described by the Drude model. Plasmonic effects in graphene were also recently observed 7 , which are important in the transition range from terahertz to infrared. Rooted in these understandings, several devices based on interband transitions have been demonstrated, including transparent electrodes 10 , photodetectors 11 , and broadband infrared electro-optical modulators 12 .…”

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confidence: 74%

“…On the basis of their peculiar band structures, single-layer graphene and Bernal-stacked bilayer graphene have been proposed for novel terahertz [3][4][5][6][7] and optoelectronic devices 8 , with some successful experimental demonstrations [9][10][11][12] . Interband and intraband transitions under optical excitation in graphene have been investigated by various groups [13][14][15][16][17][18][19] .…”

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confidence: 99%

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Broadband graphene terahertz modulators enabled by intraband transitions

et al. 2012

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Terahertz technology promises myriad applications including imaging, spectroscopy and communications. However, one major bottleneck at present for advancing this field is the lack of efficient devices to manipulate the terahertz electromagnetic waves. Here we demonstrate that exceptionally efficient broadband modulation of terahertz waves at room temperature can be realized using graphene with extremely low intrinsic signal attenuation. We experimentally achieved more than 2.5 times superior modulation than prior broadband intensity modulators, which is also the first demonstrated graphene-based device enabled solely by intraband transitions. The unique advantages of graphene in comparison to conventional semiconductors are the ease of integration and the extraordinary transport properties of holes, which are as good as those of electrons owing to the symmetric conical band structure of graphene. Given recent progress in graphene-based terahertz emitters and detectors, graphene may offer some interesting solutions for terahertz technologies.

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confidence: 74%

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confidence: 99%

Broadband graphene terahertz modulators enabled by intraband transitions

et al. 2012

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“…To fabricate next generation electronic devices incorporating graphene, it is pertinent to develop a variety of methods for direct synthesis of graphene on any substrate. However, various methods have been adopted for controlled growth of graphene, and it was found that direct growth of graphene especially on dielectrics is difficult to achieve due to their low surface energy 2, 3, 4, 5, 6, 7, 8, 9, 10, 11. However, the surface modification of dielectric substrates can facilitate the ease of nucleation of graphene 10, 12.…”

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confidence: 99%

Direct CVD Growth of Graphene on Technologically Important Dielectric and Semiconducting Substrates

et al. 2018

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To fabricate graphene based electronic and optoelectronic devices, it is highly desirable to develop a variety of metal‐catalyst free chemical vapor deposition (CVD) techniques for direct synthesis of graphene on dielectric and semiconducting substrates. This will help to avoid metallic impurities, high costs, time consuming processes, and defect‐inducing graphene transfer processes. Direct CVD growth of graphene on dielectric substrates is usually difficult to accomplish due to their low surface energy. However, a low‐temperature plasma enhanced CVD technique could help to solve this problem. Here, the recent progress of metal‐catalyst free direct CVD growth of graphene on technologically important dielectric (SiO2, ZrO2, HfO2, h‐BN, Al2O3, Si3N4, quartz, MgO, SrTiO3, TiO2, etc.) and semiconducting (Si, Ge, GaN, and SiC) substrates is reviewed. High and low temperature direct CVD growth of graphene on these substrates including growth mechanism and morphology is discussed. Detailed discussions are also presented for Si and Ge substrates, which are necessary for next generation graphene/Si/Ge based hybrid electronic devices. Finally, the technology development of the metal‐catalyst free direct CVD growth of graphene on these substrates is concluded, with future outlooks.

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“…While the plasmonic response of metals is weak at the infrared or lower frequencies, graphene plasmons exist in the THz regime with relatively low losses. [13][14][15] These facts, added to the important ingredient of tunability, make graphene a very suitable platform for the design of plasmonic metasurfaces in the THz regime. 16,17 Metasurfaces, the 2D counterpart of metamaterials, 18,19 consist of a planar arrangement of resonant subwavelength-sized building blocks.…”

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Graphene as a Tunable Anisotropic or Isotropic Plasmonic Metasurface

et al. 2016

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We demonstrate a tunable plasmonic metasurface by considering a graphene sheet subject to a periodically patterned doping level. The unique optical properties of graphene result in electrically tunable plasmons that allow for extreme confinement of electromagnetic energy in the technologically significant regime of THz frequencies.Here we add an extra degree of freedom by using graphene as a metasurface, proposing to dope it with an electrical gate patterned in the micron or sub-micron scale. By extracting the effective conductivity of the sheet we characterize metasurfaces periodically modulated along one or two directions. In the first case, and making use of the analytical insight provided by transformation optics, we show an efficient control of THz radiation for one polarization. In the second case, we demonstrate a metasurface with an isotropic response that is independent of wave polarization and orientation.Graphene, an atomically-thin layer of carbon atoms arranged in a honeycomb lattice, features outstanding mechanical, thermal and electrical properties. 1 Its characteristic linear * To whom correspondence should be addressed 1 dispersion for electrons close to the Dirac point results in the possibility of tuning the carrier concentration by external means. 2 In particular, graphene can be biased by electrical gating or surface doping, which modifies its Fermi level and permits the existence of surface plasmons propagating along graphene. Because of the two-dimensional (2D) nature of this material, the surface plasmons it supports have very short wavelengths and exhibit extreme out-of-plane confinement to the sheet, as has already been demonstrated in a number of experiments. [3][4][5][6][7][8][9][10][11] Compared to the noble metals commonly employed for plasmonics, 12 graphene has a low carrier concentration, and, for this reason, plasmons in graphene are relatively long-lived and appear at lower frequencies. While the plasmonic response of metals is weak at the infrared or lower frequencies, graphene plasmons exist in the THz regime with relatively low losses. 13-15 These facts, added to the important ingredient of tunability, make graphene a very suitable platform for the design of plasmonic metasurfaces in the THz regime. 16,17 Metasurfaces, the 2D counterpart of metamaterials, 18,19 consist of a planar arrangement of resonant subwavelength-sized building blocks. 20 By appropriately designing the blocks and their arrangement, metasurfaces provide an ultra-thin platform for manipulating electromagnetic (EM) waves. Novel phenomena and applications based on metasurfaces range from broadband light bending and anomalous reflection and refraction 21-23 to strong spin-orbit interactions of light. 24In this work, we study graphene as a plasmonic metasurface that offers the potential to control radiation in the THz regime. Different from previous studies, 16,17 which focused on patterning the graphene, here we consider a continuous graphene sheet with periodically modulated doping. This gives rise ...

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Graphene plasmonics for tunable terahertz metamaterials

Cited by 2,755 publications

References 28 publications

Broadband graphene terahertz modulators enabled by intraband transitions

Broadband graphene terahertz modulators enabled by intraband transitions

Direct CVD Growth of Graphene on Technologically Important Dielectric and Semiconducting Substrates

Graphene as a Tunable Anisotropic or Isotropic Plasmonic Metasurface

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