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Physical Review B

Quantum interferences of a single quantum dot in the case of detuning

Steffen Michaelis de Vasconcellos, Stefan Stufler, Sven‐Ake Wegner, Patrick Ester, A. Zrenner, Max Bichler A

Published Aug 16, 2006• 2 citations
Publisher

Abstract

We report on highly phase-sensitive measurements with a slightly detuned excitation of a quantum mechanical two-level system. It is formed by the single-exciton ground state of a single quantum dot, which is incorporated in a $n\text{\ensuremath{-}}i$ Schottky diode. We excite the two-level system by two partly overlapping laser pulses with variable phase shift. To investigate the properties of the quantum system we determine its occupancy by measuring the photocurrent. The experimental data are compared to a numerical simulation of the system.

DOI
10.1103/physrevb.74.081304

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Abstract We report on highly phase sensitive measurements with a slightly detuned excitation of a quantum mechanical two‐level system. It is formed by the single exciton ground state of a single quantum dot, which is incorporated in a n‐i‐Schottky diode. We excited the two‐level system by two partly overlapping laser pulses with variable phase shift. To investigate the properties of the quantum system we determine its occupancy by measuring the photocurrent. The experimental data is compared to a numerical simulation of the system. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
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We report on a two-level system, defined by the ground-state exciton of a single InGaAs∕GaAs\mathrm{In}\mathrm{Ga}\mathrm{As}∕\mathrm{Ga}\mathrm{As}InGaAs∕GaAs quantum dot. Saturation spectroscopy combined with ultrahigh spectral resolution gives us a complete description of the system in the steady-state limit. Rabi oscillations and quantum interference experiments, on the other hand, provide a detailed insight into the coherent high excitation regime. All fundamental properties of the two-level system show an excellent quantitative agreement in both domains, even though obtained under entirely different experimental conditions. We thus are able to demonstrate control over an almost ideal two-level system, suitable for possible applications in quantum information processing.
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