Regensburg 2019 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 10: Quantum information systems
HL 10.6: Talk
Monday, April 1, 2019, 16:30–16:45, H36
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
In our experiment we created a superposition state of a quantum dot exciton, whose quantum phase is subsequently manipulated by ultrafast Stark tuning. The resulting phase shift is measured by Ramsey interference. Previously 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 ultrafast BiCMOS chips for the generation of electric pulses (rise times <20 ps @ cryogenic operationality) and RF-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 phase 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 [2].
Ref: [1] S. de Vasconcellos et al., Nature Photonics 4, 545 (2010).
Ref: [2] A. Widhalm et al., Applied Physics Letters 112(11):111105 (2018).