Dresden 2011 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 71: Quantum Dots: Optical Properties

HL 71.7: Talk

Thursday, March 17, 2011, 12:00–12:15, POT 251

Faraday rotation and ellipticity signals of mode-locked spins in InGaAs quantum dots — •Steffen Varwig¹, Stefan Spatzek¹, Alexander Schwan¹, Mikhail M. Glazov², Irina A. Yugova³, Dmitri R. Yakovlev¹, Dirk Reuter⁴, Andreas D. Wieck⁴, and Manfred Bayer¹ — ¹Experimentelle Physik II, TU Dortmund, D-44221 Dortmund, Germany — ²A. F. Ioffe Physico-Technical Institute, 194021 St. Petersburg, Russia — ³Institute of Physics, St. Petersburg State University, 198504 St. Petersburg, Russia — ⁴Angewandte Festkörperphysik, Ruhr- Universität Bochum, D-44780 Bochum, Germany

We have studied the pump-probe Faraday rotation and ellipticity signals of electron spins in ensembles of singly charged (In,Ga)As/GaAs quantum dots.

For degenerate pump and probe we observe that the Faraday rotation signal amplitude first grows with increasing the time separation between pump and probe before a decay is observed for large temporal separations. The temporal behavior of the ellipticity signal, on the other hand, is regular: its amplitude decays with the separation. By contrast, for detuned pump and probe the Faraday rotation and ellipticty signals both exhibit similar and conventional behavior. The comparison between calculations and experimental data allows us to provide insight into the spectral dependence of the electron spin precession frequencies and extract the electron g factor dependence on energy [M. M. Glazov et al., Phys. Rev. B 82, 155325 (2010)].