Graphene Terahertz Plasmon Oscillators

Rana, Farhan

doi:10.1109/tnano.2007.910334

Cited by 472 publications

(377 citation statements)

References 34 publications

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“…The mechanisms responsible for electron-hole recombination in graphene could include plasmon emission, phonon emission, and Auger scattering. In general, recombination rates due to these processes are expected to have non-trivial carrier density dependencies [7,20,21,22]. Additionally, carrier generation rates cannot be ignored in the analysis [21].…”

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confidence: 99%

Ultrafast Optical-Pump Terahertz-Probe Spectroscopy of the Carrier Relaxation and Recombination Dynamics in Epitaxial Graphene

et al. 2008

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The ultrafast relaxation and recombination dynamics of photogenerated electrons and holes in epitaxial graphene are studied using optical-pump Terahertz-probe spectroscopy. The conductivity in graphene at Terahertz frequencies depends on the carrier concentration as well as the carrier distribution in energy. Time-resolved studies of the conductivity can therefore be used to probe the dynamics associated with carrier intraband relaxation and interband recombination. We report the electron-hole recombination times in epitaxial graphene for the first time. Our results show that carrier cooling occurs on sub-picosecond time scales and that interband recombination times are carrier density dependent.Graphene is a 2D lattice of carbon atoms arranged in a honeycomb crystal structure with a zero (or nearzero) bandgap and a linear energy-momentum dispersion relation for both electrons and holes [1,2]. The unique electronic and optical properties of graphene make it a promising material for the development of high-speed electron devices, including field-effect transistors, pn-diodes, Terahertz oscillators, and electronic and optical sensors [2,3,4,5,6,7]. The realization of graphene-based devices requires understanding the nonequilibrium carrier dynamics as well as the rate at which electron-hole recombination occurs.Measurements of the ultrafast intraband relaxation dynamics of photogenerated electrons and holes in epitaxial graphene using both degenerate [8] and non-degenerate [9] optical-pump optical-probe spectroscopy have been previously reported. Similar measurements for exfoliated graphene mono-and multi-layers have also been carried out [10]. These measurements were sensitive to the interband conductivity of graphene and probed the time evolution of the carrier occupation at specific energies in the bands. Consequently, they were not able to directly measure the time scales associated with carrier recombination. At room temperature, the optical response of graphene in the THz frequency range is described by the intraband conductivity -the free carrier responsewhich depends not only on the total carrier concentration but also on the carrier distribution in energy [11]. Therefore, THz radiation can be used to study the carrier relaxation and recombination dynamics in graphene. In this paper, we present results obtained from opticalpump THz-probe spectroscopy of epitaxial graphene in which the time-dependent conductivity of graphene that has been excited with an optical pump pulse is probed with a few-cycle THz pulse. We observe cooling of the photogenerated carrier distribution as well as electronhole recombination in graphene in real time. Our results indicate that the recombination times in graphene depend on the carrier density and material disorder.The epitaxial graphene samples used in this work were grown on the carbon face of semi-insulating 6H-SiC wafers using techniques that have been reported previously [12]. As discussed in [8,11], X-ray photoemission, Raman, and optical/IR/THz transmission spectroscopy ...

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Ultrafast Optical-Pump Terahertz-Probe Spectroscopy of the Carrier Relaxation and Recombination Dynamics in Epitaxial Graphene

et al. 2008

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“…In addition, the linear bandstructure and two-dimensional nature of graphene allow for it to support plasmonic modes that have a unique dispersion relation [14][15][16][17] . These plasmonic modes have been proposed as a means of efficiently coupling to THz radiation [18][19][20] , and they have been shown to create strong absorption pathways in the THz to mid-IR when the graphene is patterned to form plasmonic Fabry-Perot resonances [21][22][23][24] . The intensity and frequency of the plasmonic modes in graphene are carrier density dependent, and they display extermely large mode confinement, which allows them to efficiently couple to excitations (for example, phonons) in their environment and to create new optical modes 21,22,25,26 .…”

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confidence: 99%

Electronic modulation of infrared radiation in graphene plasmonic resonators

et al. 2015

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All matter at finite temperatures emits electromagnetic radiation due to the thermally induced motion of particles and quasiparticles. Dynamic control of this radiation could enable the design of novel infrared sources; however, the spectral characteristics of the radiated power are dictated by the electromagnetic energy density and emissivity, which are ordinarily fixed properties of the material and temperature. Here we experimentally demonstrate tunable electronic control of blackbody emission from graphene plasmonic resonators on a silicon nitride substrate. It is shown that the graphene resonators produce antenna-coupled blackbody radiation, which manifests as narrow spectral emission peaks in the mid-infrared. By continuously varying the nanoresonator carrier density, the frequency and intensity of these spectral features can be modulated via an electrostatic gate. This work opens the door for future devices that may control blackbody radiation at timescales beyond the limits of conventional thermo-optic modulation.

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“…Due to its exceptional electronic and optical properties and high resistance to deformation [4], graphene may become a key component in solar cells, light emitting diodes, flexible touch screens, ultrafast lasers and frequency converters [5]. The frequency of graphene plasma waves lies in the terahertz range [6], making graphene appealing for controllable terahertz devices such as modulators and filters, where the resonant frequency can be tuned by an external electric field or optical pumping. In recent research, various hybrid structures based on graphene/metamaterial were proposed, and their optical parameters were controlled by application of a bias voltage between metamaterial and graphene [7][8][9][10][11] or by optical pumping in the infrared frequency range [12].…”

Section: Introductionmentioning

confidence: 99%

Optically controlled terahertz filter based on graphene and cross-like metasurface

Grebenchukov¹,

Zaitsev²,

Khodzitskiy³

2017

Nanosystems: Phys. Chem. Math.

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We propose a theoretical model for the optically controlled terahertz filter based on hybrid graphene/metasurface structure. Such a device has a high accuracy for the frequency adjustment by the different intensities of the optical pumping in the infrared spectral range, fast response time and polarization independence. The tuning by optical pumping of the spectral characteristics of the filter in term of resonant frequency and Q-factor was shown.

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Graphene Terahertz Plasmon Oscillators

Cited by 472 publications

References 34 publications

Ultrafast Optical-Pump Terahertz-Probe Spectroscopy of the Carrier Relaxation and Recombination Dynamics in Epitaxial Graphene

Ultrafast Optical-Pump Terahertz-Probe Spectroscopy of the Carrier Relaxation and Recombination Dynamics in Epitaxial Graphene

Electronic modulation of infrared radiation in graphene plasmonic resonators

Optically controlled terahertz filter based on graphene and cross-like metasurface

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