Dresden 2014 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 120: Ultra-fast phenomena II
HL 120.1: Vortrag
Freitag, 4. April 2014, 11:30–11:45, POT 006
High-harmonic generation by extreme nonlinear terahertz excitation of semiconductors — •Ulrich Huttner1, Mackillo Kira1, Stephan W. Koch1, Olaf Schubert2, Matthias Hohenleutner2, Fabian Langer2, Benedikt Urbanek2, Christoph Lange2, and Rupert Huber2 — 1Department of Physics, Philipps-University Marburg, 35032 Marburg, Germany — 2Department of Physics, University of Regensburg, 93040 Regensburg, Germany
Combining theory and experimental results we demonstrate that one can access the regime of ultrafast coherent charge transport in semiconductors by applying extremely strong and ultrashort terahertz (THz) pulses with stable carrier envelope phase (CEP). Since the bandgap in semiconductors is typically much larger than the THz-photon energy, the THz excitation nonresonantly excites coherent polarization and currents. Modeling these processes with the semiconductor Bloch equations [1,2], we find that the strong THz field leads to intense high-harmonic generation (HHG) and dynamical Bloch oscillations [3]. Our experiments with a GaSe sample show harmonics up to the 22nd order. The HHG is strongly influenced by the dynamical Bloch oscillations that can be controlled via the CEP of the exciting THz-pulse.
[1] Golde, D. et al. - phys. stat. sol. b 248, 863-866 (2011).
[2] Kira, M. & Koch, S. W. - Semiconductor Quantum Optics: (Cambridge University Press, 2011).
[3] Schubert, O. et al. - Sub-cycle control of terahertz high-harmonic generation by dynamical Bloch oscillations, 2013, accepted for publication.