[{"citation":{"mla":"Roeder, Franz, et al. “Toward Integrated Sensors for Optimized Optical Coherence Tomography with Undetected Photons.” <i>Physical Review Applied</i>, vol. 25, no. 3, 034031, American Physical Society (APS), 2026, doi:<a href=\"https://doi.org/10.1103/cwsx-42c4\">10.1103/cwsx-42c4</a>.","short":"F. Roeder, R. Pollmann, V. Quiring, C. Eigner, B. Brecht, C. Silberhorn, Physical Review Applied 25 (2026).","bibtex":"@article{Roeder_Pollmann_Quiring_Eigner_Brecht_Silberhorn_2026, title={Toward integrated sensors for optimized optical coherence tomography with undetected photons}, volume={25}, DOI={<a href=\"https://doi.org/10.1103/cwsx-42c4\">10.1103/cwsx-42c4</a>}, number={3034031}, journal={Physical Review Applied}, publisher={American Physical Society (APS)}, author={Roeder, Franz and Pollmann, René and Quiring, Viktor and Eigner, Christof and Brecht, Benjamin and Silberhorn, Christine}, year={2026} }","apa":"Roeder, F., Pollmann, R., Quiring, V., Eigner, C., Brecht, B., &#38; Silberhorn, C. (2026). Toward integrated sensors for optimized optical coherence tomography with undetected photons. <i>Physical Review Applied</i>, <i>25</i>(3), Article 034031. <a href=\"https://doi.org/10.1103/cwsx-42c4\">https://doi.org/10.1103/cwsx-42c4</a>","ama":"Roeder F, Pollmann R, Quiring V, Eigner C, Brecht B, Silberhorn C. Toward integrated sensors for optimized optical coherence tomography with undetected photons. <i>Physical Review Applied</i>. 2026;25(3). doi:<a href=\"https://doi.org/10.1103/cwsx-42c4\">10.1103/cwsx-42c4</a>","chicago":"Roeder, Franz, René Pollmann, Viktor Quiring, Christof Eigner, Benjamin Brecht, and Christine Silberhorn. “Toward Integrated Sensors for Optimized Optical Coherence Tomography with Undetected Photons.” <i>Physical Review Applied</i> 25, no. 3 (2026). <a href=\"https://doi.org/10.1103/cwsx-42c4\">https://doi.org/10.1103/cwsx-42c4</a>.","ieee":"F. Roeder, R. Pollmann, V. Quiring, C. Eigner, B. Brecht, and C. Silberhorn, “Toward integrated sensors for optimized optical coherence tomography with undetected photons,” <i>Physical Review Applied</i>, vol. 25, no. 3, Art. no. 034031, 2026, doi: <a href=\"https://doi.org/10.1103/cwsx-42c4\">10.1103/cwsx-42c4</a>."},"intvolume":"        25","year":"2026","issue":"3","publication_status":"published","publication_identifier":{"issn":["2331-7019"]},"doi":"10.1103/cwsx-42c4","title":"Toward integrated sensors for optimized optical coherence tomography with undetected photons","author":[{"last_name":"Roeder","id":"88149","full_name":"Roeder, Franz","first_name":"Franz"},{"full_name":"Pollmann, René","id":"78890","last_name":"Pollmann","first_name":"René"},{"first_name":"Viktor","last_name":"Quiring","full_name":"Quiring, Viktor"},{"full_name":"Eigner, Christof","id":"13244","last_name":"Eigner","orcid":"https://orcid.org/0000-0002-5693-3083","first_name":"Christof"},{"first_name":"Benjamin","full_name":"Brecht, Benjamin","id":"27150","last_name":"Brecht","orcid":"0000-0003-4140-0556 "},{"first_name":"Christine","full_name":"Silberhorn, Christine","id":"26263","last_name":"Silberhorn"}],"date_created":"2026-03-23T12:28:33Z","volume":25,"publisher":"American Physical Society (APS)","date_updated":"2026-03-25T07:59:04Z","status":"public","abstract":[{"lang":"eng","text":"<jats:p>\r\n                    The development of practical sensors for optical coherence tomography (OCT) with undetected photons requires miniaturization via integration. To be practical, these sensors must exhibit a large spectral bandwidth and a high brightness, which are linked to a high axial resolution and a sufficient signal-to-noise ratio, respectively. Here, we combine these requirements in a scheme for OCT measurements with undetected photons based on nonlinear\r\n                    <a:math xmlns:a=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\">\r\n                      <a:mi>Ti</a:mi>\r\n                      <a:mo>:</a:mo>\r\n                      <a:msub>\r\n                        <a:mrow>\r\n                          <a:mi>Li</a:mi>\r\n                          <a:mi>Nb</a:mi>\r\n                          <a:mi mathvariant=\"normal\">O</a:mi>\r\n                        </a:mrow>\r\n                        <a:mn>3</a:mn>\r\n                      </a:msub>\r\n                    </a:math>\r\n                    waveguides. We investigate the performance benchmarks of the commonly used SU(1,1) scheme in comparison to an induced-coherence scheme and find that the latter is actually better suited when implementing measurements with undetected photons in integrated systems. In both schemes, we perform pump-gain optimization and OCT measurements with undetected photons with an axial resolution as low as\r\n                    <d:math xmlns:d=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\">\r\n                      <d:mn>28</d:mn>\r\n                      <d:mspace width=\"0.2em\"/>\r\n                      <d:mtext fontfamily=\"times\">μ</d:mtext>\r\n                      <d:mrow>\r\n                        <d:mi mathvariant=\"normal\">m</d:mi>\r\n                      </d:mrow>\r\n                    </d:math>\r\n                    .\r\n                  </jats:p>"}],"type":"journal_article","publication":"Physical Review Applied","language":[{"iso":"eng"}],"article_number":"034031","user_id":"27150","department":[{"_id":"15"},{"_id":"623"},{"_id":"288"}],"_id":"65094"},{"title":"Measurement of Ultrashort Biphoton Correlation Times with an Integrated Two-Color Broadband SU(1,1)-Interferometer","doi":"10.1103/prxquantum.5.020350","date_updated":"2024-06-01T13:00:53Z","publisher":"American Physical Society (APS)","volume":5,"author":[{"first_name":"Franz","last_name":"Roeder","id":"88149","full_name":"Roeder, Franz"},{"last_name":"Pollmann","id":"78890","full_name":"Pollmann, René","first_name":"René"},{"first_name":"Michael","last_name":"Stefszky","id":"42777","full_name":"Stefszky, Michael"},{"first_name":"Matteo","last_name":"Santandrea","orcid":"0000-0001-5718-358X","id":"55095","full_name":"Santandrea, Matteo"},{"first_name":"Kai Hong","id":"36389","full_name":"Luo, Kai Hong","last_name":"Luo","orcid":"0000-0003-1008-4976"},{"first_name":"V.","full_name":"Quiring, V.","last_name":"Quiring"},{"full_name":"Ricken, Raimund","last_name":"Ricken","first_name":"Raimund"},{"first_name":"Christof","orcid":"https://orcid.org/0000-0002-5693-3083","last_name":"Eigner","id":"13244","full_name":"Eigner, Christof"},{"id":"27150","full_name":"Brecht, Benjamin","orcid":"0000-0003-4140-0556 ","last_name":"Brecht","first_name":"Benjamin"},{"last_name":"Silberhorn","full_name":"Silberhorn, Christine","id":"26263","first_name":"Christine"}],"date_created":"2024-06-01T12:48:51Z","year":"2024","intvolume":"         5","citation":{"apa":"Roeder, F., Pollmann, R., Stefszky, M., Santandrea, M., Luo, K. H., Quiring, V., Ricken, R., Eigner, C., Brecht, B., &#38; Silberhorn, C. (2024). Measurement of Ultrashort Biphoton Correlation Times with an Integrated Two-Color Broadband SU(1,1)-Interferometer. <i>PRX Quantum</i>, <i>5</i>(2), Article 020350. <a href=\"https://doi.org/10.1103/prxquantum.5.020350\">https://doi.org/10.1103/prxquantum.5.020350</a>","mla":"Roeder, Franz, et al. “Measurement of Ultrashort Biphoton Correlation Times with an Integrated Two-Color Broadband SU(1,1)-Interferometer.” <i>PRX Quantum</i>, vol. 5, no. 2, 020350, American Physical Society (APS), 2024, doi:<a href=\"https://doi.org/10.1103/prxquantum.5.020350\">10.1103/prxquantum.5.020350</a>.","short":"F. Roeder, R. Pollmann, M. Stefszky, M. Santandrea, K.H. Luo, V. Quiring, R. Ricken, C. Eigner, B. Brecht, C. Silberhorn, PRX Quantum 5 (2024).","bibtex":"@article{Roeder_Pollmann_Stefszky_Santandrea_Luo_Quiring_Ricken_Eigner_Brecht_Silberhorn_2024, title={Measurement of Ultrashort Biphoton Correlation Times with an Integrated Two-Color Broadband SU(1,1)-Interferometer}, volume={5}, DOI={<a href=\"https://doi.org/10.1103/prxquantum.5.020350\">10.1103/prxquantum.5.020350</a>}, number={2020350}, journal={PRX Quantum}, publisher={American Physical Society (APS)}, author={Roeder, Franz and Pollmann, René and Stefszky, Michael and Santandrea, Matteo and Luo, Kai Hong and Quiring, V. and Ricken, Raimund and Eigner, Christof and Brecht, Benjamin and Silberhorn, Christine}, year={2024} }","chicago":"Roeder, Franz, René Pollmann, Michael Stefszky, Matteo Santandrea, Kai Hong Luo, V. Quiring, Raimund Ricken, Christof Eigner, Benjamin Brecht, and Christine Silberhorn. “Measurement of Ultrashort Biphoton Correlation Times with an Integrated Two-Color Broadband SU(1,1)-Interferometer.” <i>PRX Quantum</i> 5, no. 2 (2024). <a href=\"https://doi.org/10.1103/prxquantum.5.020350\">https://doi.org/10.1103/prxquantum.5.020350</a>.","ieee":"F. Roeder <i>et al.</i>, “Measurement of Ultrashort Biphoton Correlation Times with an Integrated Two-Color Broadband SU(1,1)-Interferometer,” <i>PRX Quantum</i>, vol. 5, no. 2, Art. no. 020350, 2024, doi: <a href=\"https://doi.org/10.1103/prxquantum.5.020350\">10.1103/prxquantum.5.020350</a>.","ama":"Roeder F, Pollmann R, Stefszky M, et al. Measurement of Ultrashort Biphoton Correlation Times with an Integrated Two-Color Broadband SU(1,1)-Interferometer. <i>PRX Quantum</i>. 2024;5(2). doi:<a href=\"https://doi.org/10.1103/prxquantum.5.020350\">10.1103/prxquantum.5.020350</a>"},"publication_identifier":{"issn":["2691-3399"]},"publication_status":"published","issue":"2","article_number":"020350","language":[{"iso":"eng"}],"_id":"54544","project":[{"name":"MiLiQuant: Miniaturisierte Lichtquellen für den industriellen Einsatz in Quantensensoren und Quanten-Imaging-Systemen (MiLiQuant) - Teilvorhaben: Technologie und Theorie für MIR Quanten-Imaging Systeme","_id":"207","grant_number":"13N15065"},{"name":"MIRAQLS: MIRAQLS: Mid-infrared Quantum Technology for Sensing","_id":"571","grant_number":"101070700"},{"name":"E2TPA: Exploiting Entangled Two-Photon Absorption","_id":"190"}],"department":[{"_id":"288"},{"_id":"623"}],"user_id":"88149","abstract":[{"text":"The biphoton correlation time, a measure for the conditional uncertainty in the temporal arrival of two photons from a photon pair source, is a key performance identifier for many quantum spectroscopy applications, with shorter correlation times typically yielding better performance. Furthermore, it provides fundamental insight into the effects of dispersion on the biphoton state. Here, we show that a characteristic dependence of the width of the temporal interferogram can be exploited to obtain insights into the amount of second-order dispersion inside the interferometer and to retrieve actual and Fourier-limited ultrashort biphoton correlation times of around 100 fs. In the presented scheme, we simultaneously measure spectral and temporal interferograms at the output of an SU(1,1) interferometer based on an integrated broadband parametric down conversion source in a Ti:LiNbO3 waveguide.","lang":"eng"}],"status":"public","publication":"PRX Quantum","type":"journal_article"},{"publication":"Optics Express","abstract":[{"lang":"eng","text":"<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>\r\n      <jats:italic>p</jats:italic>\r\n    </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>"}],"language":[{"iso":"eng"}],"issue":"14","year":"2024","publisher":"Optica Publishing Group","date_created":"2024-06-19T06:58:17Z","title":"Integrated, bright broadband, two-colour parametric down-conversion source","type":"journal_article","status":"public","_id":"54815","department":[{"_id":"15"},{"_id":"623"},{"_id":"288"}],"user_id":"78890","article_type":"original","article_number":"23945","publication_identifier":{"issn":["1094-4087"]},"publication_status":"published","intvolume":"        32","citation":{"ieee":"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>.","chicago":"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>.","ama":"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>","apa":"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>","mla":"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>.","short":"R. Pollmann, F. Roeder, V. Quiring, R. Ricken, C. Eigner, B. Brecht, C. Silberhorn, Optics Express 32 (2024).","bibtex":"@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} }"},"date_updated":"2025-12-19T11:37:41Z","volume":32,"author":[{"id":"78890","full_name":"Pollmann, René","last_name":"Pollmann","first_name":"René"},{"first_name":"Franz","last_name":"Roeder","id":"88149","full_name":"Roeder, Franz"},{"full_name":"Quiring, Victor","last_name":"Quiring","first_name":"Victor"},{"first_name":"Raimund","full_name":"Ricken, Raimund","last_name":"Ricken"},{"first_name":"Christof","orcid":"https://orcid.org/0000-0002-5693-3083","last_name":"Eigner","id":"13244","full_name":"Eigner, Christof"},{"orcid":"0000-0003-4140-0556 ","last_name":"Brecht","id":"27150","full_name":"Brecht, Benjamin","first_name":"Benjamin"},{"first_name":"Christine","last_name":"Silberhorn","id":"26263","full_name":"Silberhorn, Christine"}],"doi":"10.1364/oe.522549"},{"issue":"12","publication_identifier":{"issn":["1367-2630"]},"publication_status":"published","intvolume":"        26","citation":{"chicago":"Roeder, Franz, Abira Gnanavel, René Pollmann, Olga Brecht, Michael Stefszky, Laura Padberg, Christof Eigner, Christine Silberhorn, and Benjamin Brecht. “Ultra-Broadband Non-Degenerate Guided-Wave Bi-Photon Source in the near and Mid-Infrared.” <i>New Journal of Physics</i> 26, no. 12 (2024). <a href=\"https://doi.org/10.1088/1367-2630/ad9f98\">https://doi.org/10.1088/1367-2630/ad9f98</a>.","ieee":"F. Roeder <i>et al.</i>, “Ultra-broadband non-degenerate guided-wave bi-photon source in the near and mid-infrared,” <i>New Journal of Physics</i>, vol. 26, no. 12, Art. no. 123025, 2024, doi: <a href=\"https://doi.org/10.1088/1367-2630/ad9f98\">10.1088/1367-2630/ad9f98</a>.","ama":"Roeder F, Gnanavel A, Pollmann R, et al. Ultra-broadband non-degenerate guided-wave bi-photon source in the near and mid-infrared. <i>New Journal of Physics</i>. 2024;26(12). doi:<a href=\"https://doi.org/10.1088/1367-2630/ad9f98\">10.1088/1367-2630/ad9f98</a>","apa":"Roeder, F., Gnanavel, A., Pollmann, R., Brecht, O., Stefszky, M., Padberg, L., Eigner, C., Silberhorn, C., &#38; Brecht, B. (2024). Ultra-broadband non-degenerate guided-wave bi-photon source in the near and mid-infrared. <i>New Journal of Physics</i>, <i>26</i>(12), Article 123025. <a href=\"https://doi.org/10.1088/1367-2630/ad9f98\">https://doi.org/10.1088/1367-2630/ad9f98</a>","mla":"Roeder, Franz, et al. “Ultra-Broadband Non-Degenerate Guided-Wave Bi-Photon Source in the near and Mid-Infrared.” <i>New Journal of Physics</i>, vol. 26, no. 12, 123025, IOP Publishing, 2024, doi:<a href=\"https://doi.org/10.1088/1367-2630/ad9f98\">10.1088/1367-2630/ad9f98</a>.","short":"F. Roeder, A. Gnanavel, R. Pollmann, O. Brecht, M. Stefszky, L. Padberg, C. Eigner, C. Silberhorn, B. Brecht, New Journal of Physics 26 (2024).","bibtex":"@article{Roeder_Gnanavel_Pollmann_Brecht_Stefszky_Padberg_Eigner_Silberhorn_Brecht_2024, title={Ultra-broadband non-degenerate guided-wave bi-photon source in the near and mid-infrared}, volume={26}, DOI={<a href=\"https://doi.org/10.1088/1367-2630/ad9f98\">10.1088/1367-2630/ad9f98</a>}, number={12123025}, journal={New Journal of Physics}, publisher={IOP Publishing}, author={Roeder, Franz and Gnanavel, Abira and Pollmann, René and Brecht, Olga and Stefszky, Michael and Padberg, Laura and Eigner, Christof and Silberhorn, Christine and Brecht, Benjamin}, year={2024} }"},"year":"2024","volume":26,"date_created":"2024-12-27T19:01:14Z","author":[{"first_name":"Franz","full_name":"Roeder, Franz","id":"88149","last_name":"Roeder"},{"first_name":"Abira","full_name":"Gnanavel, Abira","last_name":"Gnanavel"},{"first_name":"René","last_name":"Pollmann","full_name":"Pollmann, René","id":"78890"},{"first_name":"Olga","last_name":"Brecht","full_name":"Brecht, Olga"},{"first_name":"Michael","last_name":"Stefszky","id":"42777","full_name":"Stefszky, Michael"},{"first_name":"Laura","id":"40300","full_name":"Padberg, Laura","last_name":"Padberg"},{"full_name":"Eigner, Christof","id":"13244","last_name":"Eigner","orcid":"https://orcid.org/0000-0002-5693-3083","first_name":"Christof"},{"last_name":"Silberhorn","full_name":"Silberhorn, Christine","id":"26263","first_name":"Christine"},{"first_name":"Benjamin","orcid":"0000-0003-4140-0556 ","last_name":"Brecht","full_name":"Brecht, Benjamin","id":"27150"}],"date_updated":"2025-12-19T11:36:36Z","publisher":"IOP Publishing","doi":"10.1088/1367-2630/ad9f98","title":"Ultra-broadband non-degenerate guided-wave bi-photon source in the near and mid-infrared","publication":"New Journal of Physics","type":"journal_article","status":"public","abstract":[{"text":"The latest applications in ultrafast quantum metrology require bright, broadband bi-photon sources with one of the photons in the mid-infrared and the other in the visible to near infrared. However, existing sources based on bulk crystals are limited in brightness due to the short interaction length and only allow for limited dispersion engineering. Here, we present an integrated PDC source based on a Ti:LiNbO3 waveguide that generates broadband bi-photons with central wavelengths at 860 nm and 2800 nm. Their spectral bandwidth exceeds 25 THz and is achieved by simultaneous matching of the group velocities (GVs) and cancellation of GV dispersion for the signal and idler field. We provide an intuitive understanding of the process by studying our source’s behavior at different temperatures and pump wavelengths, which agrees well with simulations.","lang":"eng"}],"department":[{"_id":"288"},{"_id":"623"},{"_id":"15"}],"user_id":"78890","_id":"57862","project":[{"_id":"571","name":"MIRAQLS: MIRAQLS: Mid-infrared Quantum Technology for Sensing"},{"name":"E2TPA: Exploiting Entangled Two-Photon Absorption","_id":"190"}],"language":[{"iso":"eng"}],"article_number":"123025","article_type":"original"}]