Dear all
Please be informed about the following Optics Colloquium.
With best regards,
Ilona Blatter
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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".
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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
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