Ramsey fringes in an electric-field-tunable quantum dot system.
We report on Ramsey fringes measured in a single InGaAs/GaAs quantum dot two-level system. We are able to control the transition energy of the system by Stark effect tuning. In combination with double pulse excitation this allows for a voltage controlled preparation of the phase and the occupancy of the two-level system. For long pulse delay times we observe extremely narrow fringes with spectral width below the homogeneous linewidth of the system. Implications on quantum information processing are discussed.
Universität Paderborn, Warburger Strasse 100, D-33098 Paderborn, Germany. stufler@physik.upb.de
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Stufler
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Ester
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Zrenner
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Bichler