article published René Pollmann author 78890 Franz Roeder author 88149 Victor Quiring author Raimund Ricken author Christof Eigner author 13244https://orcid.org/0000-0002-5693-3083 Benjamin Brecht author 271500000-0003-4140-0556 Christine Silberhorn author 26263 15 department 623 department 288 department <jats:p>Broadband quantum light is a vital resource for quantum metrology and spectroscopy applications such as quantum optical coherence tomography or entangled two photon absorption. For entangled two photon absorption in particular, very high photon flux combined with high time-frequency entanglement is crucial for observing a signal. So far these conditions could be met by using high power lasers driving degenerate, type 0 bulk-crystal spontaneous parametric down conversion (SPDC) sources. This naturally limits the available wavelength ranges and precludes deterministic splitting of the generated output photons. In this work we demonstrate an integrated two-colour SPDC source utilising a group-velocity matched lithium niobate waveguide, reaching both exceptional brightness 1.52⋅10<jats:sup>6</jats:sup>pairssmWGHz and large bandwidth (7.8 THz FWHM) while pumped with a few mW of continuous wave (CW) laser light. By converting a narrow band pump to broadband pulses the created photon pairs show correlation times of Δ<jats:italic>τ</jats:italic> ≈ 120 fs while maintaining the narrow bandwidth Δ<jats:italic>ω</jats:italic><jats:sub> <jats:italic>p</jats:italic> </jats:sub> ≪ 1 MHz of the CW pump light, yielding strong time-frequency entanglement. Furthermore our process can be adapted to a wide range of central wavelengths.</jats:p> Optica Publishing Group2024 eng 1094-408710.1364/oe.522549 3214 R. Pollmann <i>et al.</i>, “Integrated, bright broadband, two-colour parametric down-conversion source,” <i>Optics Express</i>, vol. 32, no. 14, Art. no. 23945, 2024, doi: <a href="https://doi.org/10.1364/oe.522549">10.1364/oe.522549</a>. Pollmann, René, Franz Roeder, Victor Quiring, Raimund Ricken, Christof Eigner, Benjamin Brecht, and Christine Silberhorn. “Integrated, Bright Broadband, Two-Colour Parametric down-Conversion Source.” <i>Optics Express</i> 32, no. 14 (2024). <a href="https://doi.org/10.1364/oe.522549">https://doi.org/10.1364/oe.522549</a>. Pollmann R, Roeder F, Quiring V, et al. Integrated, bright broadband, two-colour parametric down-conversion source. <i>Optics Express</i>. 2024;32(14). doi:<a href="https://doi.org/10.1364/oe.522549">10.1364/oe.522549</a> Pollmann, René, et al. “Integrated, Bright Broadband, Two-Colour Parametric down-Conversion Source.” <i>Optics Express</i>, vol. 32, no. 14, 23945, Optica Publishing Group, 2024, doi:<a href="https://doi.org/10.1364/oe.522549">10.1364/oe.522549</a>. @article{Pollmann_Roeder_Quiring_Ricken_Eigner_Brecht_Silberhorn_2024, title={Integrated, bright broadband, two-colour parametric down-conversion source}, volume={32}, DOI={<a href="https://doi.org/10.1364/oe.522549">10.1364/oe.522549</a>}, number={1423945}, journal={Optics Express}, publisher={Optica Publishing Group}, author={Pollmann, René and Roeder, Franz and Quiring, Victor and Ricken, Raimund and Eigner, Christof and Brecht, Benjamin and Silberhorn, Christine}, year={2024} } R. Pollmann, F. Roeder, V. Quiring, R. Ricken, C. Eigner, B. Brecht, C. Silberhorn, Optics Express 32 (2024). Pollmann, R., Roeder, F., Quiring, V., Ricken, R., Eigner, C., Brecht, B., &#38; Silberhorn, C. (2024). Integrated, bright broadband, two-colour parametric down-conversion source. <i>Optics Express</i>, <i>32</i>(14), Article 23945. <a href="https://doi.org/10.1364/oe.522549">https://doi.org/10.1364/oe.522549</a> 548152024-06-19T06:58:17Z2025-12-19T11:37:41Z