Bright non-classical light sources emitting single and indistinguishable photons on demand constitute an essential building block towards the realization of quantum communication networks . In recent years it turned out that single self-organized quantum dots (QDs) integrated into photonic microstructures are promising candidates for being used as efficient single-photon sources . However, related work was almost exclusively performed with structures based on statistically grown QDs in combination with random device technology. In this work we go a significant step further and report on the fabrication of spatially and spectrally aligned single QD microlenses using in-situ electron beam lithography. Apart from the practical aspect with high process yield of about 90%, our approach combines all features essential for quantum communication in a single device, namely high photon extraction efficiency, high suppression of multi-photon events and a high degree of indistinguishable photons.
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