Freiburg 2019 – wissenschaftliches Programm
FM 84.5: Poster
Donnerstag, 26. September 2019, 16:30–18:30, Tents
Polarization-preserving quantum frequency conversion for entanglement distribution in quantum networks — •Matthias Bock1, Stephan Kucera1, Robert Garthoff2, Tim van Leent2, Kai Redeker2, Pascal Eich1, Matthias Kreis1, Wenjamin Rosenfeld2,3, Tobias Bauer1, Harald Weinfurter2,3, Juergen Eschner1, and Christoph Becher1 — 1Universität des Saarlandes, Campus E2.6, Saarbrücken, Germany — 2Fakultät für Physik, Ludwig-Maximilians-Universität, Munich, Germany — 3Max-Planck-Institut für Quantenoptik, Garching, Germany
Entanglement between a stationary quantum system and a photonic flying qubit is an essential ingredient of a quantum-repeater network. Most stationary quantum bits, however, have transition wavelengths in the blue, red or near-infrared spectral regions, whereas long-range fiber-communication requires wavelengths in the low-loss telecom regime. A proven tool to interconnect flying qubits at visible/NIR wavelengths to the telecom bands is quantum frequency conversion.
Here we will show an efficient and low-noise polarization-preserving frequency converter connecting 854 nm – a transition wavelength in a single trapped 40Ca+-ion – to the Telecom O-band at 1310 nm. This enables the observation of ion-telecom-photon entanglement as well as an ion-to-telecom-photon state transfer. Moreover we will present a complete QFC system designed as telecom interface for an elementary Rubidium-atom based quantum network link. As a first result, the entanglement between a single Rb-atom and a telecom photon transmitted through an optical fiber of 10 km length is shown.