Terahertz Coherent Control of Optically Dark Paraexcitons inCu2O

Abstract

Intense multiterahertz fields of order megavolts per centimeter are used to coherently promote optically dark and dense paraexcitons in Cu2O from the 1s into the 2p state. The nonlinear field response of the intraexcitonic degrees of freedom is directly monitored in the time domain via ultrabroadband electro-optic sampling. The experimental results are analyzed with a microscopic many-body theory, identifying up to two internal Rabi cycles. The effects of population inversion and ponderomotive contributions are disentangled.

Carrier dynamics in semiconductors studied with time-resolved terahertz spectroscopy

“…IV.B.1, THz measurements on intraexcitonic transitions have recently provided a new playing field to observe quantum phenomena such as stimulated emission, quantum beats , and Rabi cycling (Leinss et al, 2008). The key advantage here lies in its electro-optic detection scheme which permits the phaseresolved probing of pump-induced polarizations with a time resolution in the subcycle regime.…”

“…The emergence of amplified Ti:sapphire systems in the 1990s (Backus et al, 1998) eventually provided the possibility to readily create charge carriers by optical means. Not only did this offer greater flexibility in generating different charge carrier densities, but it also permitted the study of systems driven out of equilibrium by optical excitation processes and to monitor the evolution Shah, 1999). This is particularly useful for the determination of the mobility in systems that possess a high density of trap states or fast electron-hole recombination channels, for instance.…”

“…This feature has so far been hard or impossible to achieve in the infrared or visible. In the following, we focus on the observation of Rabi cycles between intraexcitonic transitions in CuO 2 by Leinss et al (2008) since it provides another example of how high-field terahertz pulses can drive optical transitions in the nonlinear regime.…”

Strong-field single-cycle THz pulses generated in an organic crystal

“…[4][5][6][7] While laser-based THz radiation at frequencies 20-100 THz has been generated by difference frequency mixing in nonlinear inorganic crystals, 8 the generation of highpower THz single-cycle pulses above 1 MV/cm in the range of 0.1-10 THz, the so-called THz gap, is still challenging due to the limited availability of appropriate THz emitters. 9 Only recently, single-cycle pulses at 0.8 THz central frequency of 1 MV/cm have been demonstrated by optical rectification (OR) in LiNbO 3 (Ref.…”

Electric field ionization of gallium acceptors in germanium induced by single-cycle terahertz pulses

“…The recent development of ultra-intense THz laser systems generating phase-stable transients has enabled us to study coherent THz manipulation [7][8][9] and fascinating THz nonlinear phenomena in various materials. [10][11][12] It is claimed that the field ionization process may play a key role in these nonlinear phenomena.…”