Semiconductor quantum dots (QDs) are regarded as potential candidates for the implementation of solid state quantum computation. The basic ingredient for the realization of a quantum computer are Rabi oscillations - a sinusoidal time evolution of the population difference in a two-level system that is observed under strong resonant optical excitation [1]. In this contribution we report measurements of the damping of Rabi oscillations in InAs self-assembled QDs in the temperature range between T = 5 and 90 K. From comparison of the time domain Rabi oscillations with spectral hole burning (SHB) line-shapes we conclude that acoustic phonon-induced dephasing processes damp the Rabi oscillations. In a first experiment, SHB signals were recorded at different temperatures between T = 5 and 90 K [2]. In these measurements a pump pulse polarized parallel to the [110] direction of the sample was tuned to the maximum of the excitonic ground state transition. The polarization of the broadband-probe was set parallel to that of the pump, and the differential transmission change of the probe was measured at a temporal delay of approximately 50 ps after excitation. The excitation bandwidth of the pump pulse was set to 350 μeV (FWHM). All SHB signals show reduced absorption at the pump photon energy, corresponding to a bleaching of the 0-X transition (0...ground state, X...exciton state). In addition, induced absorption was observed which arises from the transition from the exciton state X to the biexciton state XX at an energy of ΔE = 4 meV (ΔE...biexciton binding energy) below the exciton peak.
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