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PRODID:UW-Madison-Physics-Events
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SEQUENCE:0
UID:UW-Physics-Event-3613
DTSTART:20150209T220000Z
DURATION:PT1H0M0S
DTSTAMP:20260419T154255Z
LAST-MODIFIED:20150123T220728Z
LOCATION:4272 Chamberlin Hall
SUMMARY:Surface Plasmons and Impurity States in Graphene\, R. G. Herb 
 Condensed Matter Seminar\, Victor Brar  \, California Institute of Tec
 hnology
DESCRIPTION:Graphene\, an atomically thin sheet of carbon atoms\, prov
 ides a unique platform to study quasiparticle interactions and to crea
 te optical metamaterials with novel properties.  The 2D nature and lin
 ear band structure of graphene give rise to a semi-metal behavior\, wi
 th tunable dielectric properties and a high electron mobility.  In the
  DC regime\, these properties allow graphene to display novel screenin
 g behavior in the presence of charged impurities\, which I will show c
 an be probed directly using scanning tunneling spectroscopy (STM).  At
  optical (mid-IR) frequencies\, the graphene dielectric function is st
 rongly perturbed by the presence of collective excitations known as su
 rface plasmon polaritons (SPPs)\, which are optical modes - supported 
 by free carriers - that are bound to the graphene sheet.  These modes 
 show a number of remarkable properties\, including a carrier density d
 ependent dispersion relation\, and wavelengths that are more than 100 
 times shorter than freespace.  I will show how the surface plasmons in
  graphene can be harnessed to create infrared metasurfaces that have t
 unable optical properties.  These materials will be shown to exhibit e
 xtreme light-matter interactions that can control the macroscopic abso
 rption and emission properties of nanostructured dielectric stacks.
URL:https://www.physics.wisc.edu/events/?id=3613
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