Mainz 2017 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 2: Quantum Communication I
Q 2.7: Talk
Monday, March 6, 2017, 16:15–16:30, P 3
Polarization-entangled photon pairs from a cavity-enhanced down-conversion source in Sagnac configuration — •Jan Arenskötter, Stephan Kucera, and Jürgen Eschner — Universität des Saarlandes, Experimentalphysik, Campus E2.6, 66123 Saarbrücken
An efficient resource of entanglement in atom–photon-based quantum networks are polarization-entangled photon pairs generated by type-II spontaneous parametric down-conversion.
Up to date, the best entanglement values are achieved by single-pass conversion in Sagnac configuration [1]. On the other hand, the highest pair rates are reported in cavity-enhanced sources [2]. We combine the two approaches and generate frequency-degenerate photon pairs at 854 nm wavelength in a signal- and idler-resonant bow-tie resonator with 10 MHz linewidth, tuned to resonance with the D5/2 ↔ P3/2 transition in the 40Ca+ ion. We achieve a brightness of 5.4·103 (s MHz mW)−1 fiber-coupled pairs with up to 97 % fidelity (at 20 mW pump power) to a maximally entangled state, whose phase is fully adjustable between Ψ+ and Ψ−. This source will be employed in quantum communication experiments [3].
[1] Kuzucu et al., Phys. Rev. A 77, 032314 (2008).
[2] Luo et al., New J. Phys. 17 073039 (2015).
[3] Kurz et al., Phys. Rev. A 93, 62348 (2016).