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arXiv · 1604.02262

Dynamics of excitons in individual InAs quantum dots revealed in four-wave mixing spectroscopy

Q. Mermillod·D. Wigger·V. Delmonte·D. E. Reiter·C. Schneider·M. Kamp·S. Höfling·W. Langbein·T. Kuhn·G. Nogues·J. Kasprzak
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Abstract

A detailed understanding of the population and coherence dynamics in optically driven individual emitters in solids and their signatures in ultrafast nonlinear-optical signals is of prime importance for their applications in future quantum and optical technologies. In a combined experimental and theoretical study on exciton complexes in single semiconductor quantum dots we reveal a detailed picture of the dynamics employing three-beam polarization-resolved four-wave mixing (FWM) micro-spectroscopy. The oscillatory dynamics of the FWM signals in the exciton-biexciton system is governed by the fine-structure splitting and the biexciton binding energy in an excellent quantitative agreement between measurement and analytical description. The analysis of the excitation conditions exhibits a dependence of the dynamics on the specific choice of polarization configuration, pulse areas and temporal ordering of driving fields. The interplay between the transitions in the four-level exciton system leads to rich evolution of coherence and population. Using two-dimensional FWM spectroscopy we elucidate the exciton-biexciton coupling and identify neutral and charged exciton complexes in a single quantum dot. Our investigations thus clearly reveal that FWM spectroscopy is a powerful tool to characterize spectral and dynamical properties of single quantum structures.

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Q. Mermillod, D. Wigger, V. Delmonte, D. E. Reiter, C. Schneider, M. Kamp, S. Höfling, W. Langbein, T. Kuhn, G. Nogues, J. Kasprzak. 2016-04-08. Dynamics of excitons in individual InAs quantum dots revealed in four-wave mixing spectroscopy. https://doi.org/10.1364/optica.3.000377

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