Parts | Days | Selection | Search | Updates | Downloads | Help

Q: Fachverband Quantenoptik und Photonik

Q 60: Quantum Communication, Networks, Repeaters, & QKD II

Q 60.2: Talk

Thursday, March 5, 2026, 15:00–15:15, P 10

Highly Indistinguishable Single Telecom Photons from a Tin-Vacancy-Center in Diamond — •David Lindler, Tobias Bauer, Dennis Herrmann, Robert Morsch, Marlon Schäfer, and Christoph Becher — Universität des Saarlandes, FR Physik, Campus E2.6, 66123 Saarbrücken

Tin-vacancy centers (SnV) in diamond are a promising platform for quantum nodes in quantum communication networks, exhibiting excellent optical and spin coherence [1,2]. To connect these nodes over long distances via optical fiber links, such as in a quantum repeater, it is necessary to first generate entanglement between each quantum node and a photon. The photons are then converted into the low-loss telecom C-band using quantum frequency down-conversion to mitigate the high losses associated with the visible wavelength of the SnV center photons. Performing a Bell-state measurement on the photons enables entanglement swapping, resulting in a pair of entangled remote quantum nodes. Achieving a quantum-repeater advantage over direct transmission requires the photons to be highly indistinguishable to ensure successful Bell-state measurements with high fidelity.
We present the generation of highly indistinguishable photons in the telecom band that are emitted sequentially by a single SnV center. The indistinguishability of the photons, measured via Hong-Ou-Mandel interference, reaches a visibility of over 95% before, and over 90% after frequency conversion to the telecom C-band, respectively.
[1] J. Görlitz et al., npj Quant. Inf. 8, 45 (2022).
[2] I. Karapatzakis et al., Phys. Rev. X 14, 031036 (2024).

Keywords: Quantum Frequency Conversion; Tin-Vacancy-Center; Hong-Ou-Mandel