Berlin 2018 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
HL: Fachverband Halbleiterphysik
HL 25: Focussed Session: Quantum Nanophotonics in Solid State Systems: Status, Challenges and Perspectives II (joint session HL/TT)
HL 25.4: Vortrag
Mittwoch, 14. März 2018, 10:30–10:45, EW 201
Ultrafast electric phase control of a quantum dot exciton — •Alex Widhalm1, Amlan Mukherjee1,2, Sebastian Krehs1, Björn Jonas1, Nandlal Sharma1, Peter Kölling1,2, Andreas Thiede2, Jens Förstner1,2, Dirk Reuter1, and Artur Zrenner1 — 1Physics Department, University of Paderborn — 2Department of Electrical Engineering, University of Paderborn, Paderborn 33098, Germany
The coherent control of QD excitons can be performed in Ramsey type experiments, where the QD is excited with two phase locked optical π/2 pulses seperated by a time delay. Here we present an experiment, where the first pulse defines the phase of the exciton, which is subsequently manipulated by ultrafast Stark tuning of the exciton energy. The resulting phase shift is measured by quantum interference using the second π/2 pulse. We have already shown, that the coherent phase of a QD exciton can be manipulated electrically by phase-locked RF signals[1]. Here we have designed SiGe:C BiCMOS chips for the generation of ultrafast electric pulses (rise times <20 ps @ cryogenic operationality) and ultrafast photodiodes with embedded high quality InGaAs QDs. Electric connections have been established by short distance wire bonding. This hybrid approach enables us to perform electric control synchroneous to double pulse ps laser excitation. We are able to demonstrate electrically controlled phase manipulations with magnitudes up to 3π and the electric control of the QD occupancy on time scales below the dephasing time of QD exciton.
Ref: [1] S. de Vasconcellos et al., Nature Photonics 4, 545 (2010).