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Dephasing processes in InGaAs quantum dots and quantum-dot molecules

Borri, Paola, Langbein, Wolfgang Werner, Schneider, S., Woggon, Ulrike, Schwab, Markus, Bayer, Manfred, Sellin, Roman L., Ouyang, Dongxun, Bimberg, Dieter, Fafard, S., Wasilewski, Zbigniew R. and Hawrylak, Pawel 2004. Dephasing processes in InGaAs quantum dots and quantum-dot molecules. Presented at: Quantum Dots, Nanoparticles, and Nanoclusters, San Jose, CA, 26-27 January 2004. Published in: Huffaker, Diana L. and Bhattacharya, Pallab eds. Quantum Dots, Nanoparticles, and Nanoclusters: 26-27 January, 2004, San Jose, California, USA. SPIE proceedings series , vol. 5361. Bellingham, WA: SPIE--the International Society for Optical Engineering, pp. 96-107. 10.1117/12.531544

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The dephasing time in semiconductor quantum dots and quantum-dot molecules is measured using a sensitive four-wave mixing heterodyne technique. We find a dephasing time of several hundred picoseconds at low temperature in the ground-state transition of strongly-confined InGaAs quantum dots, approaching the radiative-lifetime limit. Between 7 K and 100 K the polarization decay has two distinct components resulting in a non-Lorentzian lineshape with a zero-phonon line and a broad band from elastic exciton-acoustic phonon interactions. On a series of InAs/GaAs quantum-dot molecules having different interdot barrier thicknesses a systematic dependence of the dephasing dynamics on the barrier thickness is observed. The results show how the quantum mechanical coupling of the electronic wavefunctions in the molecules affects both the exciton radiative lifetime and the exciton-acoustic phonon interaction.

Item Type: Conference or Workshop Item (Paper)
Date Type: Publication
Status: Published
Schools: Physics and Astronomy
Subjects: Q Science > QC Physics
Uncontrolled Keywords: semiconductor nanostructures; coherent optical spectroscopy; ultrafast dynamics; excitons and phonons
Publisher: SPIE--the International Society for Optical Engineering
ISBN: 0819452696
ISSN: 0277-786X
Last Modified: 15 Apr 2020 13:15

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