Abstract-Quantum Physics With Ultrabroadband and Intense Terahertz Pulses

http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6210355

Author(s): Pashkin, A. 
University of Konstanz, Konstanz, Germany 
Junginger, F. ;  Mayer, B. ;  Schmidt, C. ;  Schubert, O. ;  Brida, D. ;  Huber, R. ;  Leitenstorfer, A. 

We present recent advances in the generation of highly intense multiterahertz transients and their application to nonlinear spectroscopy of bulk semiconductors. An optimized scheme of parametric amplification results in broadband single- or few-cycle terahertz transients with peak electric fields up to 10 or 25 MV/cm, respectively. Time-resolved four-wave mixing terahertz spectroscopy of InSb far away from the interband resonance demonstrates clear signatures of a nonperturbative regime of Rabi flopping. We qualitatively explain the observed behavior within a model of a quantum two-level system. In addition, we demonstrate the dynamical Franz–Keldysh effect in InP resolved on a subcycle timescale. The field-induced modulation of the interband optical absorption at the second harmonic of the driving terahertz field is observed in full agreement with theoretical predictions.