Stuttgart 2012 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 19: Quanteninformation: Festkörper und Photonen

Q 19.7: Talk

Monday, March 12, 2012, 18:00–18:15, V38.04

Quantum dot resonance fluorescence: the complete spectrum — •Clemens Matthiesen, Peter Humphreys, Anthony Nickolas Vamivakas, and Mete Atature — Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, United Kingdom

Quantum dot resonance fluorescence provides direct access to resonantly generated photons and has proven to be a useful technique in recent years for studying self-assembled QD spin dynamics [1-2]. Taking advantage of the optical selection rules of QD transitions and linear optical elements we achieve a signal to background ratio exceeding 1000 when driving a transition at saturation. We proceed to study the coherence of QD resonance fluorescence directly via first-order correlation measurements and via spectral measurements over six orders of magnitude in excitation power.

While first-order correlations reveal a marked dephasing dependence on the excitation power in the limit of strongly dressed states, we recover the properties of textbook atomic systems in the low power limit, where emission is dominated by elastic scattering [3]. Here, the single photons emitted by the QD are no longer restricted to obey the T2<2T1 relationship and show coherence times of tens of nanoseconds, ultimately limited by laser coherence. Applications of elastic scattering to shaping spectra of single photons will be discussed.

[1] C.-Y. Lu et al., Phys. Rev. B 81, 035332 (2010)

[2] A. N. Vamivakas et al., Nature 467, 297 (2010)

[3] C. Matthiesen et al., arXiv:1109.3412v1 (2011)