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Q: Fachverband Quantenoptik und Photonik

Q 60: Quantum Information II

Q 60.15: Poster

Donnerstag, 17. März 2022, 16:30–18:30, P

Two-Stage Quantum Frequency Down-Conversion of Single Photons from Silicon-Vacancy Centers in Diamond — •Marlon Schäfer, Benjamin Kambs, Dennis Herrmann, Tobias Bauer, and Christoph Becher — Universität des Saarlandes, FR Physik, Campus E2 6, 66123 Saarbrücken

The silicon-vacancy (SiV) center in diamond is a promising system as qubit for quantum communication networks due to its long spin coherence time, fourier-limited linewidth and all-optical coherent spin control. Since SiV centers show optical transitions in the visible red spectral range, quantum frequency conversion (QFC) to low-loss telecommunication wavelengths is vital for fiber-linked networks [1]. However, direct conversion schemes suffer from strong conversion-induced noise caused by Raman scattering and SPDC of the pump beam [2].

Here, we present efficient and low-noise QFC of single photons emitted by SiV centers into the telecom C-band using a two-stage conversion scheme. Through difference frequency generation in PPLN waveguides SiV photons at 737 nm are first converted to 999 nm followed by a conversion to 1549 nm. As a key advantage, the large spectral distance to the pump wavelength at 2813 nm bypasses SPDC noise and minimizes Raman noise. Thereby, we achieve a low unconditional conversion noise of less than 1 photon/s/GHz, an overall external conversion efficiency of 29 % and preservation of the single photon statistics.

[1] Bock, M. et al., Nat Commun 9, 1998 (2018).

[2] Zaske, S. et al., Opt. Express 19, 12825-12836 (2011).