Detuning dependence of Rabi oscillations in an InAs self-assembled quantum dot ensemble

Suzuki, T. and Singh, R. and Bayer, M. and Ludzwig, A. and Wieck, A.D. and Cundiff, S.T.

Volume: 97 Pages:
DOI: 10.1103/PhysRevB.97.161301
Published: 2018

We study the coherent evolution of an InAs self-assembled quantum dot (QD) ensemble in the ultrafast regime. The evolution of the entire frequency distribution is revealed by performing prepulse two-dimensional (2D) coherent spectroscopy. Charged and neutral QDs display distinct nonlinear responses arising from two-level trion and four-level exciton-biexciton systems, respectively, and each signal is clearly separated in 2D spectra. Whereas the signals for charged QDs are symmetric with respect to the detuning, those for neutral QDs are asymmetric due to the asymmetric four-level energy structure. Experimental results for charged and neutral QDs are well reproduced by solving the optical Bloch equations, including detuning and excitation-induced dephasing (EID) effects. The temperature dependence suggests that wetting-layer carriers play an important role in EID. © 2018 American Physical Society.

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