Ultrafast coherent optical manipulation of a single electron spin in a quantum dot

ORAL

Abstract

A key ingredient for spin-based quantum information processing is the coherent rotation of a spin state on timescales much faster than the spin coherence time. By applying off-resonant, picosecond-scale optical pulses, we demonstrate the coherent rotation of a single electron spin in a GaAs quantum dot (QD) through arbitrary angles up to $\pi$ rad.\footnote{ J. Berezovsky, M.H. Mikkelsen, N.G. Stoltz, L.A. Coldren, D.D. Awschalom, {\em Submitted}, (2007)} We directly observe this spin manipulation using time-resolved Kerr rotation spectroscopy\footnote{ M.H. Mikkelsen, J. Berezovsky, N.G. Stoltz, L.A. Coldren, D.D. Awschalom, {\em Nature Physics} \textbf{3}, 770 (2007)} at T=10K. Measurements of the spin rotation as a function of laser detuning and intensity confirm that the optical Stark effect is the operative mechanism and the results are well-predicted by a model including the electron-nuclear spin interaction. Using short tipping pulses and QDs with long spin coherence times, this technique enables one to perform a large number of operations within the coherence time.

*We acknowledge support from NSF and AFOSR.

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Authors

  • M.H. Mikkelsen

  • Jesse Berezovsky

    • Center for Spintronics and Quantum Computation, University of California, Santa Barbara, CA 93106

  • N.G. Stoltz

  • L.A. Coldren

  • David Awschalom

    • University of California, Santa Barbara
    • University of Californai Santa Barbara
    • Center for Spintronics and Quantum Computation, University of California, Santa Barbara, CA 93106
    • Center for Spintronics and Quantum Computation, University of California, Santa Barbara, CA
    • Center for Spintronics and Quantum Computation-University of California, Santa Barbara, CA
    • Dept. of Physics, University of California, Santa Barbara
    • Center for Spintronics and Quantum Computation, University of California, Santa Barbara