Dresden 2017 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 16: Ultrafast Phenoma II

HL 16.1: Invited Talk

Monday, March 20, 2017, 14:45–15:15, POT 51

The role of phonons for the optical control of semiconductor quantum dots — •Doris Reiter — Institut für Festkörpertheorie, Universität Münster, Wilhelm-Klemm-Str. 10, 48149 Münster, Germany

Semiconductor quantum dots are a versatile source of single or entangled photons, hence a high fidelity control of the quantum dot states is required. For semiconductor quantum dots, which are embedded in a crystal matrix, the optical control is greatly influenced by the electron-phonon interaction. Here, I will discuss the phonon influence for different types of excitation mechanisms. For an excitation with pulses having a constant frequency, Rabi oscillations of the electronic system occur, which are damped due to the electron-phonon interaction. Fascinatingly, the phonon influence depends non-trivially on the excitation power. At sufficiently high pulse intensity, phonons become less influential and a reappearance of Rabi rotations has been predicted. Experimentally this reappearance has not been observed, yet. Using an excitation with chirped laser pulses, the electron-phonon interaction can also deteriorate the state preparation. Again, for sufficiently high pulse intensity a decoupling of the phonons takes place, but in contrast to Rabi rotations at lower excitation power. Therefore it has been recently possible to experimentally enter the reappearance regime in excellent agreement with theoretical predictions. In my talk, I will present the latest results on phonon effects on optical control of quantum dots comparing the two excitation scenarios.