Speaker
Michael Fogler
(UC San Diego)
Description
Z. Fei, A. S. Rodin, G. O. Andreev, A. S. McLeod, M. Wagner, M. M. Fogler,
D. N. Basov,
Department of Physics, University of California San Diego,
9500 Gilman Drive, La Jolla, California 92093, USA
L. M. Zhang,
Department of Physics, Boston University,
590 Commonwealth Avenue, Boston, Massachusetts 02215, USA
W. Bao, Zeng Zhao, C. N. Lau,
Department of Physics and Astronomy, University of California, Riverside,
California 92521, USA
G. Dominguez, M. Thiemens,
Department of Chemistry, University of
California San Diego, 9500 Gilman Drive, La Jolla, California 92093
A. H. Castro-Neto,
Graphene Research Centre and Department of Physics,
National University of Singapore, 2 Science Drive 3, 117542, Singapore
F. Keilmann,
Max Planck Institute of Quantum Optics and Center for Nanoscience, 85714 Garching, Germany
Graphene is a novel plasmonic medium whose electronic and optical properties can be conveniently controlled by electrostatic gates. Near-field nano-imaging shows that at technologically relevant infrared frequencies common graphene/Si oxide/Si back-gated structures support surface plasmons with wavelength of the order of 200 nm and the propagation length several times this distance. Such plasmons represent concentration of electromagnetic energy on the spatial scale two orders of magnitude smaller than the photon wavelength. Both the amplitude and the wavelength of the plasmons are shown to be tunable by the gate voltage. Plasmon standing waves arise when plasmons launched by a sharp tip of a scanned probe interfere with their reflection off sample edges and inhomogeneities. These interference patterns are shown to depend on the location of the tip and the shape of the sample. Theoretical modeling provides quantitatively accurate description of the plasmonic interference patterns. Plasmonic dispersion and damping, extracted from the spatial decay of the interference fringes sheds light on the exotic electrodynamics of Dirac quasiparticles in graphene.
Primary author
Michael Fogler
(UC San Diego)
