Abstract-Thermal plasmonic interconnects in graphene

Baoan Liu, Yongmin Liu, and Sheng Shen

https://journals.aps.org/prb/abstract/10.1103/PhysRevB.90.195411

As one emerging plasmonic material, graphene can support surface plasmons at infrared and terahertz frequencies with unprecedented properties due to the strong interactions between graphene and low-frequency photons. Since graphene surface plasmons exist in the infrared and terahertz regime, they can be thermally pumped (excited) by the infrared evanescent waves emitted from an object. Here we show that thermal graphene plasmons can be efficiently excited and have monochromatic and tunable spectra, thus paving a way to harness thermal energy for graphene plasmonic devices. We further demonstrate that “thermal information communication” via graphene surface plasmons can be potentially realized by effectively harnessing thermal energy from various heat sources, e.g., the waste heat dissipated from nanoelectronic devices. These findings open up an avenue of thermal plasmonics based on graphene for different applications ranging from infrared emission control, to information processing and communication, to energy harvesting.

DOI: http://dx.doi.org/10.1103/PhysRevB.90.195411

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Abstract-Tunable terahertz radiation from graphene induced by moving electrons

Phys. Rev. B 89, 245434 – Published 20 June 2014

Tianrong Zhan, Dezhuan Han, Xinhua Hu, Xiaohan Liu, Siu-Tat Chui, and Jian Zi

https://journals.aps.org/prb/abstract/10.1103/PhysRevB.89.245434

Based on a structure consisting of a single graphene layer situated on periodic dielectric gratings, we show theoretically that terahertz radiation can be generated by low-energy electron bunches moving atop the graphene layer. The THz emission arises from graphene plasmons excited efficiently by the moving electrons. We find that the radiation intensity can be strongly enhanced due to the local field enhancement of graphene plasmons arising from their low losses and high confinement. Importantly, the radiation frequency can be tuned over a wide spectral range by varying the Fermi level of the graphene layer. Our results could find applications in developing tunable and miniature free-electron terahertz radiation sources.

DOI: http://dx.doi.org/10.1103/PhysRevB.89.245434

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Presentation-Graphene Plasmonics and Terahertz Photonics

Tuesday, April 29, 2014 - 3:30pm

Regents 109

Dennis Drew

Department of Physics, University of Maryland

http://www.physics.georgetown.edu/colloquia/2014/4/29/graphene-plasmonics-and-terahertz-photonics

The experimental discovery of two-dimensional (2D) gated graphene in 2004 by Novoselov and Geim is a seminal event in electronic materials science, ushering in a tremendous outburst of scientific activity in the study of electronic properties of this unique two-dimensional material with a gapless Dirac electronic spectrum. The lack of a traditional bandgap makes graphene an exceptionally versatile photonic material, and the ability to dope graphene through metallic contacts and tune the carrier density through the application of a gate opens possibilities for a variety of transformative photonic devices. In particular highly doped graphene has recently been recognized as a powerful plasmonic material that combines many important properties at terahertz (THz) frequencies with the ability of being electrically tunable. Terahertz radiation has uses from security to medicine. Currently, however, THz technology is notoriously underdeveloped. Graphene plasmonics has promise of filling in this conspicuous gap in the electromagnetic spectrum with a robust and radically new technology. Recently, sensitive room temperature THz detectors have been demonstrated that operate on a photo-thermo-electric principle with response times of 10s of femtoseconds. THz absorption in a graphene element raises the temperature of the graphene carriers, which then diffuse to the contacts made of dissimilar metals and produces a photo voltage proportional to the Seebeck coefficient of the graphene. A source of THz radiation based on this photo-thermo-electric effect also looks promising. A graphene element is used as an optical mixer of near IR to generate THz plasmons which are then coupled to free space radiation by an antenna. A review of graphene and these THz developments will be described.

Host: 

 Paola Barbara

Discussion Leader: 

 Paola Barbara

Abstract-Graphene Plasmonics for Terahertz to Mid-Infrared Applications

Tony Low, Phaedon Avouris

(Submitted on 12 Mar 2014)

http://arxiv.org/abs/1403.2799

In recent years, we have seen a rapid progress in the field of graphene plasmonics, motivated by graphene's unique electrical and optical properties, tunabilty, long-lived collective excitation and their extreme light confinement. Here, we review the basic properties of graphene plasmons; their energy dispersion, localization and propagation, plasmon-phonon hybridization, lifetimes and damping pathways. The application space of graphene plasmonics lies in the technologically significant, but relatively unexploited terahertz to mid-infrared regime. We discuss emerging and potential applications, such as modulators, notch filters, polarizers, mid-infrared photodetectors, mid-infrared vibrational spectroscopy, among many others.

Abstract-Tunable terahertz radiation from graphene induced by moving electrons

http://eprintweb.org/S/article/cond-mat/1402.2829

T. R. Zhan, D. Z. Han, X. H. Hu, X. H. Liu, S. T. Chui and J. Zi

Department of Physics, Key laboratory of Micro and Nano Photonic Structures (Ministry of Education), and Key Laboratory of Surface Physics, Fudan University, Shanghai 200433, P. R. China Department of Applied Physics, College of Physics, Chongqing University, Chongqing 400044, P. R. China Bartol Research Institute, University of Delaware, Newark, Delaware 19716, USA Department of Materials Science and Laboratory of Advanced Materials, Fudan University, Shanghai 200433, P. R. China

Received. 12 February 2014  Last updated. 12 February 2014

Abstract. Based on a structure consisting of a single graphene layer situated on a periodic dielectric grating, we show theoretically that intense terahertz (THz) radiations can be generated by an electron bunch moving atop the graphene layer. The underlying physics lies in the fact that a moving electron bunch with rather low electron energy ($sim$1 keV) can efficiently excite graphene plasmons (GPs) of THz frequencies with a strong confinement of near-fields. GPs can be further scattered into free space by the grating for those satisfying the phase matching condition. The radiation patterns can be controlled by varying the velocity of the moving electrons. Importantly, the radiation frequencies can be tuned by varying the Fermi level of the graphene layer, offering tunable THz radiations that can cover a wide frequency range. Our results could pave the way toward developing tunable and miniature THz radiation sources based on graphene.

Abstract-Graphene Plasmonics for Terahertz to Mid-Infrared Applications

Tony Low * and Phaedon Avouris *

IBM T.J. Watson Research Center, 1101 Kitchawan Road, Yorktown Heights, New York 10598, United States

http://pubs.acs.org/doi/abs/10.1021/nn406627u

In recent years, we have seen a rapid progress in the field of graphene plasmonics, motivated by graphene’s unique electrical and optical properties, tunability, long-lived collective excitation and its extreme light confinement. Here, we review the basic properties of graphene plasmons: their energy dispersion, localization and propagation, plasmon–phonon hybridization, lifetimes and damping pathways. The application space of graphene plasmonics lies in the technologically significant, but relatively unexploited terahertz to mid-infrared regime. We discuss emerging and potential applications, such as modulators, notch filters, polarizers, mid-infrared photodetectors, and mid-infrared vibrational spectroscopy, among many others.