Events at Physics |
Events on Monday, February 9th, 2015
- Plasma Physics (Physics/ECE/NE 922) Seminar
- The tokamak density limit: a thermo-resistive disruption mechanism
- Time: 12:00 pm - 1:00 pm
- Place: 1610 Engineering Hall
- Speaker: Dr. David Gates, Princeton Plasma Physics Laboratory
- Host: UW
- R. G. Herb Condensed Matter Seminar
- Faculty Candidate Seminar
- Surface Plasmons and Impurity States in Graphene
- Time: 4:00 pm
- Place: 4272 Chamberlin Hall
- Speaker: Victor Brar , California Institute of Technology
- Abstract: Graphene, an atomically thin sheet of carbon atoms, provides a unique platform to study quasiparticle interactions and to create optical metamaterials with novel properties. The 2D nature and linear band structure of graphene give rise to a semi-metal behavior, with tunable dielectric properties and a high electron mobility. In the DC regime, these properties allow graphene to display novel screening behavior in the presence of charged impurities, which I will show can be probed directly using scanning tunneling spectroscopy (STM). At optical (mid-IR) frequencies, the graphene dielectric function is strongly perturbed by the presence of collective excitations known as surface 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 dependent 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 tunable optical properties. These materials will be shown to exhibit extreme light-matter interactions that can control the macroscopic absorption and emission properties of nanostructured dielectric stacks.
- Host: Coppersmith