Hannover 2020 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 39: Posters: Quantum Optics and Photonics III
Q 39.40: Poster
Mittwoch, 11. März 2020, 16:30–18:30, Empore Lichthof
Efficient single-photon collection for long-distance entanglement of atoms — •Matthias Seubert1, Robert Garthoff1, Tim van Leent1, Kai Redeker1, Derya Taray1, Wei Zhang1, Wenjamin Rosenfeld1,2, and Harald Weinfurter1,2 — 1Fakultät für Physik, Ludwig-Maximilians-Universität, Munich, Germany — 2Max-Planck-Institut für Quantenoptik, Garching, Germany
An essential role in future quantum communication applications, such as quantum repeaters and quantum networks, will be entanglement between quantum memories seperated over large distances. Currently, the entanglement generation rate of single atoms in schemes based on entanglement swapping is limited by the collection efficiency of emitted photons. To overcome this limit, new optics for optimizing the collection efficiency of single photons, emitted by an optically trapped Rb-87 atom was designed. Here we describe the implementation of this new custom designed high-NA microscope objective and its characterization. We obtained an improvement of the photon collection efficiency by a factor of 2.5, which will increase the atom-atom entanglement rate by a factor of 6 with regard to [1]. Furthermore, simulations show that the coupling efficiency of photons into single-mode-fibres can be further increased by 5% using a custom designed fiber collimator. The improved collection efficiency was mendatory to compensate the loss in frequency conversion such that we could demonstrate long distance entaglement between an atom and a photon over 20 km of fiber [2].
[1] W. Rosenfeld, Phys. Rev. Lett. 119, 010402 (2017)
[2] T. van Leent, arXiv:1909.01006 (2019)