Regensburg 2010 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 28: FS: Time-Resolved Spectroscopy in Correlated Electron Systems:
Experiment and Theory
TT 28.6: Talk
Thursday, March 25, 2010, 12:00–12:15, H18
Quantum interference between photo-excited states in a solid-state Mott insulator — •Simon Wall1,5, Daniele Brida2, Stephen R. Clark3,1, Dieter Jaksch1,3, Arzhang Ardavan1, Stefano Bonora2, Giulio Cerullo2, and Andrea Cavalleri1,4 — 1Department of Physics, Clarendon Laboratory, Oxford UK — 2Dipartimento di Fisica, Politecnico di Milano, Italy — 3Centre for Quantum Technologies, National University of Singapore — 4Max Planck Research Group for Structural Dynamics, University of Hamburg-CFEL — 5Department of Physical Chemistry, Fritz Haber Institute of the Max Planck Society, Berlin, Germany
We show that, by measuring on an ultrafast timescale, the coherent quantum evolution of a correlated solid after photoexcitation can be observed during the first few femtoseconds. By using nearly-single-cycle, sub-10 fs IR pulses, we measure the time-dependent evolution of the optical conductivity in the quasi-1D organic ET-F2TCNQ after photoexcitation. By comparing our results to numerical calculations we are able to identify two regimes, one incoherent regime occurring on long timescales in which the dynamics are dictated by the electronic population in the excited state, and a second, coherent regime occurring within the first 40 fs, where interference effects between excited states dictates the dynamics. These experiments bridge the gap between fully coherent temporal evolution observed in optical lattices and the incoherent dynamics usually observed in condensed phase materials.