Berlin 2012 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 74: Focus Session: Semiconductor-based Quantum Communication I

HL 74.1: Hauptvortrag

Donnerstag, 29. März 2012, 09:30–10:00, ER 164

A highly efficient single photon - single quantum dot interface — •P. Senellart, O. Gazzano, S. Michaelis de Vasconcellos, C. Arnold, V. Loo, A. Nowak, A. Dousse, A. Lemaitre, I. Sagnes, J. Bloch, P. Voisin, and L. Lanco — CNRS, Laboratoire de Photonique et de Nanostructures, UPR20, 91460 Marcoussis, France

A quantum dot (QD) in a microcavity is a promising system to build a solid-state quantum network. It can be an efficient quantum light source as well as a quantum memory, a Bell-state analyser or a remote photon entangler when the QD embeds a spin. However, for these applications, one needs a perfect interface between the QD and the external electromagnetic field. We report on the scalable fabrication of ultrabright sources of indistinguishable single photons. Full control of the coupling of QDs to well designed micropillar cavity modes allows to obtain sources with collection efficiencies as high as 70%. Moreover, the Purcell effect as well as the spectral filtering of the QD emission by the cavity mode allows to further increase the effective brightness of the source by an order magnitude. Indistinguishability of the photons is demonstrated with a mean-wave packet overlap around 75%. Using high quality factor cavities operating in the strong coupling regime, we also report on resonant reflectivity measurements. When increasing the excitation power, optical non-linearities are observed when the intracavity photon number reaches 0.5. The good matching of the pillar mode with a Gaussian laser beam ensures that one out of three external photons couples to the quantum dot optical transition.