SAMOP 2023 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 17: Integrated Photonics I (joint session Q/QI)
Q 17.3: Talk
Tuesday, March 7, 2023, 11:45–12:00, E001
Ultrabright and narrowband intra-fiber biphoton source at ultralow pump power — •Alexander Bruns1, Chia-Yu Hsu1,3, Sergiy Stryzhenko1,2, Enno Giese1, Leonid Yatsenko2, Ite Yu3,4, Thomas Halfmann1, and Thorsten Peters1 — 1TU Darmstadt, Germany — 2National Academy of Science of Ukraine, Kyiv, Ukraine — 3National Tsing Hua University, Hsinchu, Taiwan — 4Center for Quantum Technology, Hsinchu, Taiwan
Nonclassical photon sources of high brightness are key components of quantum communication technologies. We here demonstrate the generation of narrowband, nonclassical photon pairs by employing spontaneous four-wave mixing in an optically-dense ensemble of cold atoms within a hollow-core fiber.
The brightness of our source approaches the limit of achievable generated spectral brightness at which successive photon pairs start to overlap in time. For a generated spectral brightness per pump power of up to 2× 109 pairs/(s MHz mW) we observe nonclassical correlations at pump powers below 100 nW and a narrow bandwidth of 2π× 6.5 MHz. In this regime we demonstrate that our source can be used as a heralded single-photon source. By further increasing the brightness we enter the regime where successive photon pairs start to overlap in time and the cross-correlation approaches a limit corresponding to thermal statistics.
Our approach of combining the advantages of atomic ensembles and waveguide environments is an important step toward photonic quantum networks of ensemble-based elements.