title: Graphene plasmonics for tunable terahertz metamaterials.
abstract: Plasmons describe collective oscillations of electrons. They have a fundamental role in the dynamic responses of electron systems and form the basis of research into optical metamaterials. Plasmons of two-dimensional massless electrons, as present in graphene, show unusual behaviour that enables new tunable plasmonic metamaterials and, potentially, optoelectronic applications in the terahertz frequency range. Here we explore plasmon excitations in engineered graphene micro-ribbon arrays. We demonstrate that graphene plasmon resonances can be tuned over a broad terahertz frequency range by changing micro-ribbon width and in situ electrostatic doping. The ribbon width and carrier doping dependences of graphene plasmon frequency demonstrate power-law behaviour characteristic of two-dimensional massless Dirac electrons. The plasmon resonances have remarkably large oscillator strengths, resulting in prominent room-temperature optical absorption peaks. In comparison, plasmon absorption in a conventional two-dimensional electron gas was observed only at 4.2 K (refs 13, 14). The results represent a first look at light-plasmon coupling in graphene and point to potential graphene-based terahertz metamaterials.
authors: Department of Physics, University of California at Berkeley, Berkeley, California                 94720, USA.
authors: Long
authors: L
authors: Ju
authors: Baisong
authors: B
authors: Geng
authors: Jason
authors: J
authors: Horng
authors: Caglar
authors: C
authors: Girit
authors: Michael
authors: M
authors: Martin
authors: Zhao
authors: Z
authors: Hao
authors: Hans A
authors: HA
authors: Bechtel
authors: Xiaogan
authors: X
authors: Liang
authors: Alex
authors: A
authors: Zettl
authors: Y Ron
authors: YR
authors: Shen
authors: Feng
authors: F
authors: Wang
mesh_terms: D004583:Electrons; D006108:Graphite; D020349:Surface Plasmon Resonance
chemical_list: D006108:Graphite