Dresden 2014 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 30: Poster: Quantum dots and wires: Preparation, characterization, optical properties and transport

HL 30.21: Poster

Montag, 31. März 2014, 17:00–20:00, P2

Quantum coherence in semiconductor quantum dot molecules — •Stephan Michael1, Weng Wah Chow2, and Hans Christian Schneider11Department of Physics, University of Kaiserslautern, P.O. Box 3049, 67653 Kaiserslautern, Germany — 2Sandia National Laboratories, Albuquerque, NM 87185-1086, USA

Quantum coherence effects such as electromagnetically induced transparency and amplification without inversion are well known in atomic few-level systems. Quantum dots, which are arguably the closest realization of an atomic-like system in semiconductors, are natural candidates for the realization of quantum coherence phenomena in solids. However, typical room temperature dephasing times limit the achievable quantum coherence effects. We present theoretical results of electromagnetically induced transparency and group-velocity slowdown for optical pulses in InGaAs-based double quantum dot molecules. These are designed to exhibit a long lived coherence between two electronic levels whereby a V-type pump-probe scheme for the investigation of quantum coherence effects is achievable. We apply a many-particle approach including microscopic scattering and dephasing based on realistic semiconductor parameters that allows us to calculate the spatio-temporal material dynamics coupled to the propagating optical field. The dependences of slowdown and shape of the propagating probe pulses on lattice temperature and pump intensities are investigated. The probe pulse slowdown in the double quantum dot molecule is shown to be substantially higher than what is achievable from similar transitions in typical InGaAs-based single quantum dots.

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