Berlin 2015 – wissenschaftliches Programm
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SYSD: Symposium SKM Dissertation-Prize 2015
SYSD 1: Symposium SKM Dissertation-Prize 2015
SYSD 1.4: Hauptvortrag
Montag, 16. März 2015, 12:15–12:40, HE 101
Dynamical Bloch oscillations and terahertz high-harmonic generation in bulk semiconductors — •Olaf Schubert1, Matthias Hohenleutner1, Fabian Langer1, Benedikt Urbanek1, Christoph Lange1, Ulrich Huttner2, Daniel Golde2, Torsten Meier3, Mackillo Kira2, Stephan W. Koch2, and Rupert Huber1 — 1University of Regensburg, Germany — 2University of Marburg, Germany — 3University of Paderborn, Germany
In 1934, Clarence Zener predicted that electrons in a crystalline solid should perform an oscillatory motion when a strong electric field is applied. Observing this counter-intuitive phenomenon in bulk solids has remained a challenge. Here, we control coherent charge transport in a semiconductor on femtosecond timescales via atomically strong multi-THz fields. The phase-locked waveforms off-resonantly drive coherent inter- and intraband excitations in the regime of dynamical Bloch oscillations, resulting in the emission of phase-stable high-order harmonics covering a frequency band of 12.7 optical octaves between 0.1 and 675 THz, a new bandwidth record for phase-stable femtosecond pulses. Interference of different excitation pathways allows for sensitive control of the generation process via the phase of the driving waveform. The experimental findings are well explained by a quantum many-body theory, identifying dynamical Bloch oscillations as the dominant source of high-harmonic generation. Demonstrating a novel crossover between optics and ultrafast transport, our experiments pave the way towards future electronics at optical clock rates.