Dresden 2011 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 28: Quantum Information: Quantum Communication 1

Q 28.2: Talk

Wednesday, March 16, 2011, 10:45–11:00, SCH A01

Highly Efficient Frequency Conversion at the Single Photon Level — Sebastian Zaske, •Andreas Lenhard, and Christoph Becher — Universität des Saarlandes, FR 7.2 Experimentalphysik, Campus E2.6, 66123 Saarbrücken

Much recent progress has been achieved in the fabrication of single photon emitters based on color centers in diamond, e.g., SiV-centers emitting at 738 nm [1]. However, efficient single photon transmission in future quantum networks requires wavelengths in the low loss band of optical fibers around 1550 nm. In order to bridge this wavelength gap we aim at frequency downconversion of single photons emitted from a SiV-center. As a first step we investigate difference frequency mixing of attenuated laser pulses at 738 nm with a strong continuous light field at 1404 nm in a ZnO-doped periodically poled LiNbO₃ ridge waveguide and yield converted photons at 1557 nm. An internal conversion efficiency exceeding 80% is achieved. Together with a high coupling efficiency of 93% into the waveguide at 738 nm this leads to an overall conversion efficiency of about 30% for our setup. We further investigate the noise properties of the mixing process by measuring the spectrum between 1450-1600 nm. The dominating noise source in our experiment is identified to be spontaneous (Stokes) Raman scattering induced by the strong pump field at 1404 nm.

[1] E. Neu, D. Steinmetz, J. Riedrich-Möller, S. Gsell, M. Fischer, M. Schreck, and C. Becher, “Single photon emission from silicon-vacancy centres in CVD-nano-diamonds on iridium,” accepted for publication in New. J. Phys. (2010).