Berlin 2018 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 13: Poster Session I
HL 13.11: Poster
Montag, 12. März 2018, 17:30–19:30, Poster B
Impact of non-resonant terahertz excitation on excitons in MoSe2 monolayer — •Tommaso Venanzi1,2, Stephan Winnerl1, Alexej Pashkin1, Manfred Helm1,2, and Harald Schneider1 — 1Helmholtz-Zentrum Dresden-Rossendorf, 01314 Dresden, Germany — 2Technische Universität Dresden, 01062 Dresden, Germany
We have studied the interaction of excitons in MoSe2 monolayers with high terahertz electric fields by means of THz pump - optical probe spectroscopy. The experiment has been performed with the free electron laser at the Helmholtz-Zentrum Dresden-Rossendorf synchronized to a mode-locked Ti:Sapphire laser. Various frequencies in the range of 3 - 30 THz have been selected for non-resonant pumping of the MoSe2 monolayer, while the probe beam (748 nm) is resonant with the exciton. During the time overlap between the picosecond THz and NIR pulses, we observe a significant reflectivity increase at the exciton resonance. We discuss free carrier absorption, excitonic dynamical Franz-Keldysh effect and AC Stark effect as possible scenarios for this non-resonant interaction.