Dresden 2009 – wissenschaftliches Programm

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SYSC: Symposium Spin Coherence in Solids

SYSC 1: Spin Coherence in Solids

SYSC 1.3: Hauptvortrag

Mittwoch, 25. März 2009, 10:30–11:00, BAR SCHÖ

Quantum dot spins in optical microcavities — •Rudolf Bratschitsch — Department of Physics and Center for Applied Photonics, University of Konstanz, D-78457 Konstanz, Germany

Spins in semiconductor quantum dots are promising candidates for qubits in quantum information processing. Photons might mediate an effective exchange interaction between quantum dot spins, if they were embedded in a strong-coupling optical cavity. Ultrafast all-optical quantum processing devices operating with femtosecond light pulses and without electrical contacts may be envisioned. Requirements for a successful experimental implementation of this concept are long spin coherence times and high cavity Q-factors.

In this talk we describe our efforts to reach this goal. We investigate the ultrafast spin dephasing of wide bandgap colloidal ZnO quantum dots [1], which are promising for room-temperature operation. Furthermore, they allow for spin coherence control via isotope engineering. High-quality optical microcavities with embedded colloidal quantum dots are fabricated [2, 3]. Finally, we present routes to the monolithic integration of semiconductor quantum dots and optical cavities via sputtering techniques [4].

References: [1] N. Janßen et al., Nano Lett. 8, 1991 (2008), [2] M. Kahl et al., Nano Lett. 7, 2897 (2007), [3] T. Thomay et al., Opt. Expr. 16, 9791 (2008), [4] G. Mayer et al., Nanotechnology, in press (2008).