Dear all

Please be informed about the following Optics Colloquium.

With best regards,

Ilona Blatter ------------------------------------------------------------ Invitation to Optics Colloquium next Friday: Date: Friday, 20.05.11

Time: 14:00

Location: ETH Zurich, Hönggerberg Campus, HCI J-3

Speaker: Tony F. Heinz, Departments of Physics and Electrical Engineering, Columbia University, New York Title: Seeing electrons in two-dimensions: Optical sprectroscopy of graphene

Abstract:

Optical spectroscopy provides an excellent means of understanding the distinctive properties of electrons in the two-dimensional system of graphene. Within the simplest picture, one has a (zero-gap) semiconductor with direct transitions between the well-known conical bands. This picture gives rise to a predicted frequency-dependent absorption of pa = 2.3%, where a is the fine-structure constant. We will demonstrate that this relation is indeed satisfied in an appropriate spectral range in the near infrared, but that at higher photon energies electron-hole interactions significantly modify this result through the formation of saddle-point excitons. Optical spectroscopy also permits a detailed analysis of how the linear bands of graphene, corresponding to massless Dirac Fermions, are modified to yield massive electrons through interlayer interactions in bilayer and few-layer graphene sheets. The observation of a tunable band gap in bilayer and trilayer graphene will also be discussed. We will also discuss recent measurements in which the electron and phonon dynamics are investigated by ultrafast pump-probe spectroscopy. Host: Atac Imamoglu, Quantum Photonics, IQE

For a complete OPTICS COLLOQUIUM schedule and up-to-date information please go to http://www.opteth.ethz.ch/news/optics_colloquium. If you don’t want to receive this invitation, please send an email to the above address with the subject line "unsubscribe".

---------------------------------------------------- ETH Zurich Dr. Andreas Heinle Coordinator optETH Laboratory of Physical Chemistry CH-8093 Zurich, Switzerland Phone +41 44 633 6871 Fax +41 44 633 1316

www.opteth.ethz.ch ----------------------------------------------------

------------------------------------------------------------------------------------------------------ ETH Zurich Dr. Ilona Blatter NCCR QSIT Coordinator Laboratory for Solid State Physics HPF E 17 Schafmattstrasse 16 8093 Zurich

ilona.blatter@phys.ethz.ch www.nccr-qsit.ethz.ch

Phone: +41 44 633 36 06 Home: +41 44 844 42 50