Dresden 2017 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 63: Poster: Quantum Dots and Optics

HL 63.64: Poster

Mittwoch, 22. März 2017, 15:00–19:00, P1A

Build-up of electron spin precession modes upon pulsed optical excitation in (In,Ga)As/GaAs quantum dots — •Eiko Evers¹, Vasilii Belykh¹, Alex Greilich¹, Dmitri Yakovlev^1,2, Dirk Reuter³, Andreas Wieck⁴, and Manfred Bayer^1,2 — ¹Experimentelle Physik 2, TU Dortmund University, 44221 Dortmund, Germany — ²Ioffe Physical-Technical Institute, Russian Academy of Sciences, 194021 Saint Petersburg, Russia — ³Optoelectronic Materials and Devices, Paderborn University, 33098 Paderborn, Germany — ⁴Angewandte Festkörperphysik, Ruhr-Universität Bochum, 44780 Bochum, Germany

The electron-spin orientation of an ensemble of singly charged quantum dots with a periodic train of laser pulses in an external magnetic field leads to spin precession mode-locking. The recently developed extended pump-probe technique enables to tailor the number of polarizing pump pulses as well as to vary the delay of the probe pulse with a resolution limited only by the pulse duration over a time of several laser repetition periods. It is used to measure the electron-spin polarization build-up in the time domain as well as to monitor the decay of spin polarization after a given number of polarizing pulses which gives the mode structure of the electron-spin precession. Subsequently, we applied a continuous radio-frequency electromagnetic field decoupling the nuclear spin bath from the electron-spin polarization. This gives us the opportunity to study the build-up without nuclear effects such as frequency focusing and allows to determine their influence on the precession modes build-up.