Dresden 2006 – wissenschaftliches Programm
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HL: Halbleiterphysik
HL 50: Poster II
HL 50.84: Poster
Donnerstag, 30. März 2006, 16:30–19:00, P3
Coherence time of single photons from laterally coupled InGaAs/GaAs quantum dot molecules — •Serkan Ates1, Sven M. Ulrich1, Mohamed Benyoucef2, Armando Rastelli2, Lijuan Wang2, Oliver G. Schmidt2, and Peter Michler1 — 15. Physikalisches Institut,Universität Stuttgart, Pfaffenwaldring 57 D - 70550 Stuttgart — 2Max-Planck-Institut für Festkörperforschung Heisenbergstr. D-70569 Stuttgart
In this work, we report detailed investigations on the coherence length of single photons from laterally coupled InGaAs/GaAs quantum dots. The lateral coupled QDs were grown on GaAs substrates by a unique combination of molecular beam epitaxy and in-situ layer precise etching [1]. The samples were cooled to 4 K and optically pumped by a continuous-wave Ti:sapphire laser at a pump wavelength of 800 nm. Our measurements were performed using a Michelson interferometer combined with a micro-photoluminescence (µ-PL) setup and a Hanbury Brown and Twiss setup. The visibility of the interferometer setup was over 90 % with the Ti:sapphire laser. We have observed excitonic and biexcitonic transitions and the visibility curve of the transitions showed a Gaussian behavior. We get the coherence length of transitions in the range of 30 - 40 ps, corresponding to a linewidth of approx. 40 µeV by using the Gaussian fitting. These results indicate that decoherence processes are present even at low temperatures. [1] R. Songmuang, S. Kiravittaya, and O. G. Schmidt, APL 82,2892 (2003)