Phonon-Assisted Population Inversion of a Single InGaAs/GaAs Quantum Dot by Pulsed Laser Excitation

Titelangaben

Quilter, John H. ; Brash, A. J. ; Liu, Feng ; Glässl, Martin ; Barth, Andreas M. ; Axt, Vollrath Martin ; Ramsay, A. J. ; Skolnick, Maurice S. ; Fox, A. M.:
Phonon-Assisted Population Inversion of a Single InGaAs/GaAs Quantum Dot by Pulsed Laser Excitation.
In: Physical Review Letters. Bd. 114 (2015) Heft 13 . - 137401.
ISSN 1079-7114
DOI: https://doi.org/10.1103/PhysRevLett.114.137401

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Abstract

We demonstrate a new method to realize the population inversion of a single InGaAs/GaAs quantum dot excited by a laser pulse tuned within the neutral exciton phonon sideband. In contrast to the conventional method of inverting a two-level system by performing coherent Rabi oscillation, the inversion is achieved by rapid thermalization of the optically dressed states via incoherent phonon-assisted relaxation. A maximum exciton population of 0.67±0.06 is measured for a laser tuned 0.83 meV to higher energy. Furthermore, the phonon sideband is mapped using a two-color pump-probe technique, with its spectral form and magnitude in very good agreement with the result of path-integral calculations.