Letter abstract


Nature Physics 3, 770 - 773 (2007)
Published online: 7 October 2007 | doi:10.1038/nphys736

Subject Categories: Electronics, photonics and device physics | Condensed-matter physics | Nanotechnology | Optical physics | Quantum physics

Optically detected coherent spin dynamics of a single electron in a quantum dot

M. H. Mikkelsen, J. Berezovsky, N. G. Stoltz, L. A. Coldren & D. D. Awschalom

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The ability to sequentially initialize, manipulate and read out the state of a qubit, such as an electron spin in a quantum dot (QD), is a requirement in virtually any scheme for quantum information processing1, 2, 3. However, previous optical measurements of a single electron spin have focused on time-averaged detection, with the spin being initialized and read out continuously4, 5, 6, 7, 8. Here, we monitor the coherent evolution of an electron spin in a single QD. We use time-resolved Kerr rotation (KR) spectroscopy, an all-optical, non-destructive technique that enables us to monitor the precession of the spin in a superposition of Zeeman-split sublevels with nanosecond time resolution. The data show an exponential decay of the spin polarization with time, and directly reveal the g-factor and spin lifetime of the electron in the QD. Furthermore, the observed spin dynamics provide a sensitive probe of the local nuclear spin environment.

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  1. Center for Spintronics and Quantum Computation, University of California, Santa Barbara, California 93106, USA

Correspondence to: D. D. Awschalom e-mail: awsch@physics.ucsb.edu




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