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HL: Fachverband Halbleiterphysik
HL 13: Optical properties
HL 13.4: Talk
Tuesday, March 24, 2009, 10:15–10:30, BEY 118
Two-color pump-probe spectroscopy of self-assembled GaAs/AlGaAs quantum dots — •Christian Wolpert1,2, Manuel Huber1,2, Markus Lippitz1,2, Lijuan Wang3, Armando Rastelli3, and Oliver G. Schmidt3 — 1Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany — 24. Physikalisches Institut, Universität Stuttgart, Germany — 3Institut für Integrative Nanowissenschaften, IFW Dresden, Germany
Semiconductor quantum dots (QDs) are a promising candidate for the realization of qbits in quantum computing. With coherence times of below 1 ns, manipulation and read-out of the quantum mechanical state requires ultrafast laser pulses. In order to address single QDs, we can restrict ourselves to optical far-field microscopy, as our GaAs/AlGaAs QD samples show QD densities well below 1/µ m2. We present a scheme for ultrafast spectroscopy of single QDs using a pump-probe technique with a confocal laser-scanning microscope. Pump and probe pulses are derived from a 150 fs pulse by spectral pulse shaping. Single exciton transitions were identified in µ-photoluminescence (µ-PL) measurements around 1.73 eV. Our approach is to resonantly pump and probe excitonic states, enabling us to directly control the phase and population dynamics in the QD. We present the experimental setup as well as first results.