--- _id: '65094' abstract: - lang: eng text: "\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 \ \r\n \ Ti\r\n :\r\n \ \r\n \r\n Li\r\n \ Nb\r\n O\r\n \ \r\n 3\r\n \ \r\n \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 \r\n 28\r\n \ \r\n μ\r\n \r\n m\r\n \r\n \r\n \ .\r\n " article_number: '034031' author: - first_name: Franz full_name: Roeder, Franz id: '88149' last_name: Roeder - first_name: René full_name: Pollmann, René id: '78890' last_name: Pollmann - first_name: Viktor full_name: Quiring, Viktor last_name: Quiring - first_name: Christof full_name: Eigner, Christof id: '13244' last_name: Eigner orcid: https://orcid.org/0000-0002-5693-3083 - 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 citation: ama: Roeder F, Pollmann R, Quiring V, Eigner C, Brecht B, Silberhorn C. Toward integrated sensors for optimized optical coherence tomography with undetected photons. Physical Review Applied. 2026;25(3). doi:10.1103/cwsx-42c4 apa: Roeder, F., Pollmann, R., Quiring, V., Eigner, C., Brecht, B., & Silberhorn, C. (2026). Toward integrated sensors for optimized optical coherence tomography with undetected photons. Physical Review Applied, 25(3), Article 034031. https://doi.org/10.1103/cwsx-42c4 bibtex: '@article{Roeder_Pollmann_Quiring_Eigner_Brecht_Silberhorn_2026, title={Toward integrated sensors for optimized optical coherence tomography with undetected photons}, volume={25}, DOI={10.1103/cwsx-42c4}, 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} }' 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.” Physical Review Applied 25, no. 3 (2026). https://doi.org/10.1103/cwsx-42c4. 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,” Physical Review Applied, vol. 25, no. 3, Art. no. 034031, 2026, doi: 10.1103/cwsx-42c4.' mla: Roeder, Franz, et al. “Toward Integrated Sensors for Optimized Optical Coherence Tomography with Undetected Photons.” Physical Review Applied, vol. 25, no. 3, 034031, American Physical Society (APS), 2026, doi:10.1103/cwsx-42c4. short: F. Roeder, R. Pollmann, V. Quiring, C. Eigner, B. Brecht, C. Silberhorn, Physical Review Applied 25 (2026). date_created: 2026-03-23T12:28:33Z date_updated: 2026-03-25T07:59:04Z department: - _id: '15' - _id: '623' - _id: '288' doi: 10.1103/cwsx-42c4 intvolume: ' 25' issue: '3' language: - iso: eng publication: Physical Review Applied publication_identifier: issn: - 2331-7019 publication_status: published publisher: American Physical Society (APS) status: public title: Toward integrated sensors for optimized optical coherence tomography with undetected photons type: journal_article user_id: '27150' volume: 25 year: '2026' ... --- _id: '65096' abstract: - lang: eng text: "\r\n Precise measurements of both the arrival time and carrier frequency of light pulses are essential for time–frequency-encoded quantum technologies. Quantum mechanics, however, imposes fundamental limits on the simultaneous determination of these quantities. In this work, we derive and experimentally verify the quantum uncertainty bounds governing joint time–frequency measurements. We show that when detection is restricted to finite time windows, the problem is naturally described by a quantum rotor, rendering the commonly used Heisenberg uncertainty relation inapplicable. We further propose an optimal detection scheme that saturates these fundamental limits. By sampling the\r\n \ Q\r\n -function, we demonstrate the reconstruction of the Wigner function beyond the harmonic oscillator. Using an experimental implementation based on a quantum pulse gate, we confirm that the proposed scheme approaches the ultimate quantum limit for simultaneous time–frequency measurements. These results provide a framework for joint time–frequency detection with direct implications for precision measurements and quantum information processing.\r\n " article_number: '548' author: - first_name: Patrick Fabian full_name: Folge, Patrick Fabian id: '88605' last_name: Folge - first_name: Laura Maria full_name: Serino, Laura Maria id: '88242' last_name: Serino - first_name: Ladislav full_name: Mišta, Ladislav last_name: Mišta - 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 - first_name: Jaroslav full_name: Řeháček, Jaroslav last_name: Řeháček - first_name: Zdeněk full_name: Hradil, Zdeněk last_name: Hradil citation: ama: Folge PF, Serino LM, Mišta L, et al. Quantum-limited detection of the arrival time and the carrier frequency of time-dependent signals. Optica. 2026;13(3). doi:10.1364/optica.579459 apa: Folge, P. F., Serino, L. M., Mišta, L., Brecht, B., Silberhorn, C., Řeháček, J., & Hradil, Z. (2026). Quantum-limited detection of the arrival time and the carrier frequency of time-dependent signals. Optica, 13(3), Article 548. https://doi.org/10.1364/optica.579459 bibtex: '@article{Folge_Serino_Mišta_Brecht_Silberhorn_Řeháček_Hradil_2026, title={Quantum-limited detection of the arrival time and the carrier frequency of time-dependent signals}, volume={13}, DOI={10.1364/optica.579459}, number={3548}, journal={Optica}, publisher={Optica Publishing Group}, author={Folge, Patrick Fabian and Serino, Laura Maria and Mišta, Ladislav and Brecht, Benjamin and Silberhorn, Christine and Řeháček, Jaroslav and Hradil, Zdeněk}, year={2026} }' chicago: Folge, Patrick Fabian, Laura Maria Serino, Ladislav Mišta, Benjamin Brecht, Christine Silberhorn, Jaroslav Řeháček, and Zdeněk Hradil. “Quantum-Limited Detection of the Arrival Time and the Carrier Frequency of Time-Dependent Signals.” Optica 13, no. 3 (2026). https://doi.org/10.1364/optica.579459. ieee: 'P. F. Folge et al., “Quantum-limited detection of the arrival time and the carrier frequency of time-dependent signals,” Optica, vol. 13, no. 3, Art. no. 548, 2026, doi: 10.1364/optica.579459.' mla: Folge, Patrick Fabian, et al. “Quantum-Limited Detection of the Arrival Time and the Carrier Frequency of Time-Dependent Signals.” Optica, vol. 13, no. 3, 548, Optica Publishing Group, 2026, doi:10.1364/optica.579459. short: P.F. Folge, L.M. Serino, L. Mišta, B. Brecht, C. Silberhorn, J. Řeháček, Z. Hradil, Optica 13 (2026). date_created: 2026-03-23T12:30:02Z date_updated: 2026-03-25T07:59:23Z department: - _id: '15' - _id: '623' - _id: '288' doi: 10.1364/optica.579459 intvolume: ' 13' issue: '3' language: - iso: eng publication: Optica publication_identifier: issn: - 2334-2536 publication_status: published publisher: Optica Publishing Group status: public title: Quantum-limited detection of the arrival time and the carrier frequency of time-dependent signals type: journal_article user_id: '27150' volume: 13 year: '2026' ... --- _id: '63451' abstract: - lang: eng text: Superconducting nanowire single-photon detectors (SNSPDs) can enable photon-number resolution (PNR) based on accurate measurements of the detector’s response time to few-photon optical pulses. In this work, we investigate the impact of the optical pulse shape and duration on the accuracy of this method. We find that Gaussian temporal pulse shapes yield cleaner arrival-time histograms and, thus, more accurate PNR, compared to bandpass-filtered pulses of equal bandwidth. For low system jitter and an optical pulse duration comparable to the other jitter contributions, photon numbers can be discriminated in our system with a commercial SNSPD. At 60 ps optical pulse duration, photon-number discrimination is significantly reduced. Furthermore, we highlight the importance of using the correct arrival-time histogram model when analyzing photon-number assignment. Using exponentially modified Gaussian distributions, instead of the commonly used Gaussian distributions, we can more accurately determine photon-number misidentification probabilities. Finally, we reconstruct the positive operator-valued measures of the detector, revealing sharp features that indicate the intrinsic PNR capabilities. article_number: '016102' author: - first_name: Timon full_name: Schapeler, Timon id: '55629' last_name: Schapeler orcid: 0000-0001-7652-1716 - first_name: Isabell full_name: Mischke, Isabell last_name: Mischke - first_name: Fabian full_name: Schlue, Fabian id: '63579' last_name: Schlue - first_name: Michael full_name: Stefszky, Michael id: '42777' last_name: Stefszky - 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 - first_name: Tim full_name: Bartley, Tim id: '49683' last_name: Bartley citation: ama: Schapeler T, Mischke I, Schlue F, et al. Practical considerations for assignment of photon numbers with SNSPDs. APL Quantum. 2026;3(1). doi:10.1063/5.0304127 apa: Schapeler, T., Mischke, I., Schlue, F., Stefszky, M., Brecht, B., Silberhorn, C., & Bartley, T. (2026). Practical considerations for assignment of photon numbers with SNSPDs. APL Quantum, 3(1), Article 016102. https://doi.org/10.1063/5.0304127 bibtex: '@article{Schapeler_Mischke_Schlue_Stefszky_Brecht_Silberhorn_Bartley_2026, title={Practical considerations for assignment of photon numbers with SNSPDs}, volume={3}, DOI={10.1063/5.0304127}, number={1016102}, journal={APL Quantum}, publisher={AIP Publishing}, author={Schapeler, Timon and Mischke, Isabell and Schlue, Fabian and Stefszky, Michael and Brecht, Benjamin and Silberhorn, Christine and Bartley, Tim}, year={2026} }' chicago: Schapeler, Timon, Isabell Mischke, Fabian Schlue, Michael Stefszky, Benjamin Brecht, Christine Silberhorn, and Tim Bartley. “Practical Considerations for Assignment of Photon Numbers with SNSPDs.” APL Quantum 3, no. 1 (2026). https://doi.org/10.1063/5.0304127. ieee: 'T. Schapeler et al., “Practical considerations for assignment of photon numbers with SNSPDs,” APL Quantum, vol. 3, no. 1, Art. no. 016102, 2026, doi: 10.1063/5.0304127.' mla: Schapeler, Timon, et al. “Practical Considerations for Assignment of Photon Numbers with SNSPDs.” APL Quantum, vol. 3, no. 1, 016102, AIP Publishing, 2026, doi:10.1063/5.0304127. short: T. Schapeler, I. Mischke, F. Schlue, M. Stefszky, B. Brecht, C. Silberhorn, T. Bartley, APL Quantum 3 (2026). date_created: 2026-01-05T10:00:58Z date_updated: 2026-03-25T08:00:27Z department: - _id: '15' - _id: '623' - _id: '288' doi: 10.1063/5.0304127 intvolume: ' 3' issue: '1' language: - iso: eng main_file_link: - open_access: '1' oa: '1' project: - _id: '191' name: 'PhoQuant: Photonische Quantencomputer - Quantencomputing Testplattform' - _id: '239' name: 'ERC-Grant: QuESADILLA: Quantum Engineering Superconducting Array Detectors in Low-Light Applications' publication: APL Quantum publication_identifier: issn: - 2835-0103 publication_status: published publisher: AIP Publishing status: public title: Practical considerations for assignment of photon numbers with SNSPDs type: journal_article user_id: '27150' volume: 3 year: '2026' ... --- _id: '65095' abstract: - lang: eng text: "\r\n We provide experimental validation of tight entropic uncertainty relations for the Shannon entropies of observables with mutually unbiased eigenstates in high dimensions. In particular, we address the cases of dimensions\r\n \r\n \ \r\n d\r\n =\r\n \ 3\r\n \r\n \ \r\n , 4, and 5 and consider from 2 to\r\n \r\n \ \r\n d\r\n +\r\n \ 1\r\n \r\n \ \r\n mutually unbiased bases. The experiment is based on pulsed frequency bins measured with a multioutput quantum pulse gate, which can perform projective measurements on a complete high-dimensional basis in the time-frequency domain. Our results fit the theoretical predictions: the bound on the sum of the entropies is never violated and is saturated by the states that minimize the uncertainty relations.\r\n " article_number: '032420' author: - first_name: Laura Maria full_name: Serino, Laura Maria id: '88242' last_name: Serino - first_name: Giovanni full_name: Chesi, Giovanni last_name: Chesi - first_name: Benjamin full_name: Brecht, Benjamin id: '27150' last_name: Brecht orcid: '0000-0003-4140-0556 ' - first_name: Lorenzo full_name: Maccone, Lorenzo last_name: Maccone - first_name: Chiara full_name: Macchiavello, Chiara last_name: Macchiavello - first_name: Christine full_name: Silberhorn, Christine id: '26263' last_name: Silberhorn citation: ama: Serino LM, Chesi G, Brecht B, Maccone L, Macchiavello C, Silberhorn C. Experimental entropic uncertainty relations in dimensions three to five. Physical Review A. 2026;113(3). doi:10.1103/f6c4-jtlc apa: Serino, L. M., Chesi, G., Brecht, B., Maccone, L., Macchiavello, C., & Silberhorn, C. (2026). Experimental entropic uncertainty relations in dimensions three to five. Physical Review A, 113(3), Article 032420. https://doi.org/10.1103/f6c4-jtlc bibtex: '@article{Serino_Chesi_Brecht_Maccone_Macchiavello_Silberhorn_2026, title={Experimental entropic uncertainty relations in dimensions three to five}, volume={113}, DOI={10.1103/f6c4-jtlc}, number={3032420}, journal={Physical Review A}, publisher={American Physical Society (APS)}, author={Serino, Laura Maria and Chesi, Giovanni and Brecht, Benjamin and Maccone, Lorenzo and Macchiavello, Chiara and Silberhorn, Christine}, year={2026} }' chicago: Serino, Laura Maria, Giovanni Chesi, Benjamin Brecht, Lorenzo Maccone, Chiara Macchiavello, and Christine Silberhorn. “Experimental Entropic Uncertainty Relations in Dimensions Three to Five.” Physical Review A 113, no. 3 (2026). https://doi.org/10.1103/f6c4-jtlc. ieee: 'L. M. Serino, G. Chesi, B. Brecht, L. Maccone, C. Macchiavello, and C. Silberhorn, “Experimental entropic uncertainty relations in dimensions three to five,” Physical Review A, vol. 113, no. 3, Art. no. 032420, 2026, doi: 10.1103/f6c4-jtlc.' mla: Serino, Laura Maria, et al. “Experimental Entropic Uncertainty Relations in Dimensions Three to Five.” Physical Review A, vol. 113, no. 3, 032420, American Physical Society (APS), 2026, doi:10.1103/f6c4-jtlc. short: L.M. Serino, G. Chesi, B. Brecht, L. Maccone, C. Macchiavello, C. Silberhorn, Physical Review A 113 (2026). date_created: 2026-03-23T12:29:23Z date_updated: 2026-03-25T07:59:36Z department: - _id: '15' - _id: '623' - _id: '288' doi: 10.1103/f6c4-jtlc intvolume: ' 113' issue: '3' language: - iso: eng publication: Physical Review A publication_identifier: issn: - 2469-9926 - 2469-9934 publication_status: published publisher: American Physical Society (APS) status: public title: Experimental entropic uncertainty relations in dimensions three to five type: journal_article user_id: '27150' volume: 113 year: '2026' ... --- _id: '65575' abstract: - lang: eng text: For the ever-growing field of quantum information processing, large-scale, efficient multiport interferometers serving as photonic processors are required. In this context, the suitability of quantum walks as the interferometric base for universal computation has been theoretically proven. In this work, we bridge the gap between theoretical proposals and state-of-the-art experimental capabilities by providing the recipe for the implementation of a universal photonic processor in discrete-time quantum walks. Specifically, we present the protocol for translating arbitrary linear transformations into the coin and step operator of a quantum walk and map these to the experimental parameters of the established time-multiplexed platform [A. Schreiber , Phys. Rev. Lett. , 050502 (2010)]. We show that our interface is highly scalable and resource efficient due to the hybrid encoding consisting of multiple degrees of freedom. Finally, we prove that our system is highly resilient against experimental imperfections and show that it compares favorably against existing architectures. article_number: '054011' author: - first_name: Jonas full_name: Lammers, Jonas last_name: Lammers - first_name: Laura full_name: Ares, Laura last_name: Ares - first_name: Federico full_name: Pegoraro, Federico id: '88928' last_name: Pegoraro - first_name: Philip full_name: Held, Philip id: '68236' last_name: Held - first_name: Benjamin full_name: Brecht, Benjamin id: '27150' last_name: Brecht orcid: '0000-0003-4140-0556 ' - first_name: Jan full_name: Sperling, Jan id: '75127' last_name: Sperling orcid: 0000-0002-5844-3205 - first_name: Christine full_name: Silberhorn, Christine id: '26263' last_name: Silberhorn citation: ama: Lammers J, Ares L, Pegoraro F, et al. Resource-efficient universal photonic processors based on time-multiplexed hybrid architectures. Physical Review Applied. 2026;25(5). doi:10.1103/x99y-2sms apa: Lammers, J., Ares, L., Pegoraro, F., Held, P., Brecht, B., Sperling, J., & Silberhorn, C. (2026). Resource-efficient universal photonic processors based on time-multiplexed hybrid architectures. Physical Review Applied, 25(5), Article 054011. https://doi.org/10.1103/x99y-2sms bibtex: '@article{Lammers_Ares_Pegoraro_Held_Brecht_Sperling_Silberhorn_2026, title={Resource-efficient universal photonic processors based on time-multiplexed hybrid architectures}, volume={25}, DOI={10.1103/x99y-2sms}, number={5054011}, journal={Physical Review Applied}, publisher={American Physical Society (APS)}, author={Lammers, Jonas and Ares, Laura and Pegoraro, Federico and Held, Philip and Brecht, Benjamin and Sperling, Jan and Silberhorn, Christine}, year={2026} }' chicago: Lammers, Jonas, Laura Ares, Federico Pegoraro, Philip Held, Benjamin Brecht, Jan Sperling, and Christine Silberhorn. “Resource-Efficient Universal Photonic Processors Based on Time-Multiplexed Hybrid Architectures.” Physical Review Applied 25, no. 5 (2026). https://doi.org/10.1103/x99y-2sms. ieee: 'J. Lammers et al., “Resource-efficient universal photonic processors based on time-multiplexed hybrid architectures,” Physical Review Applied, vol. 25, no. 5, Art. no. 054011, 2026, doi: 10.1103/x99y-2sms.' mla: Lammers, Jonas, et al. “Resource-Efficient Universal Photonic Processors Based on Time-Multiplexed Hybrid Architectures.” Physical Review Applied, vol. 25, no. 5, 054011, American Physical Society (APS), 2026, doi:10.1103/x99y-2sms. short: J. Lammers, L. Ares, F. Pegoraro, P. Held, B. Brecht, J. Sperling, C. Silberhorn, Physical Review Applied 25 (2026). date_created: 2026-05-07T07:00:08Z date_updated: 2026-05-07T07:01:09Z department: - _id: '623' - _id: '15' - _id: '170' - _id: '706' - _id: '429' doi: 10.1103/x99y-2sms intvolume: ' 25' issue: '5' language: - iso: eng publication: Physical Review Applied publication_identifier: issn: - 2331-7019 publication_status: published publisher: American Physical Society (APS) status: public title: Resource-efficient universal photonic processors based on time-multiplexed hybrid architectures type: journal_article user_id: '75127' volume: 25 year: '2026' ... --- _id: '65847' abstract: - lang: eng text: Simulating vibronic spectra is a central task in physical chemistry, offering insight into important properties of molecules. Recently, it has been experimentally demonstrated that photonic platforms based on Gaussian boson sampling (GBS) are capable of performing these simulations. However, whether an actual GBS approach is required depends on the molecule under investigation. To develop a better understanding on the requirements for simulating vibronic spectra, we explore connections between theoretical approximations in physical chemistry and their photonic counterparts. Mapping these approximations into photonics, we show that for certain molecules the GBS approach is unnecessary. We place special emphasis on the linear coupling approximation, which in photonics corresponds to sampling from multiple coherent states. By implementing this approach in experiments, we demonstrate improved similarities over previously reported GBS results for formic acid and identify the particular attributes that a molecule must exhibit for this, and other approximations, to be valid. These results highlight the importance in forming deeper connections between traditional methods and photonic approaches. article_number: '89' article_type: original author: - first_name: Jan-Lucas full_name: Eickmann, Jan-Lucas id: '73665' last_name: Eickmann orcid: 0009-0008-6524-7684 - first_name: Kai-Hong full_name: Luo, Kai-Hong id: '36389' last_name: Luo orcid: 0000-0003-1008-4976 - first_name: Mikhail full_name: Roiz, Mikhail id: '114114' last_name: Roiz - first_name: Jonas full_name: Lammers, Jonas last_name: Lammers - first_name: Simone full_name: Atzeni, Simone id: '98338' last_name: Atzeni - first_name: Cheeranjiv full_name: Pandey, Cheeranjiv last_name: Pandey - first_name: Florian full_name: Lütkewitte, Florian last_name: Lütkewitte - first_name: Reza G. full_name: Shirazi, Reza G. last_name: Shirazi - first_name: Fabian full_name: Schlue, Fabian id: '63579' last_name: Schlue - first_name: Benjamin full_name: Brecht, Benjamin id: '27150' last_name: Brecht orcid: '0000-0003-4140-0556 ' - first_name: Vladimir V. full_name: Rybkin, Vladimir V. last_name: Rybkin - first_name: Michael full_name: Stefszky, Michael id: '42777' last_name: Stefszky - first_name: Christine full_name: Silberhorn, Christine id: '26263' last_name: Silberhorn citation: ama: 'Eickmann J-L, Luo K-H, Roiz M, et al. Bridging chemistry and Gaussian boson sampling: a photonic hierarchy of approximations for molecular vibronic spectra. npj Quantum Information. 2026;12(1). doi:10.1038/s41534-026-01250-x' apa: 'Eickmann, J.-L., Luo, K.-H., Roiz, M., Lammers, J., Atzeni, S., Pandey, C., Lütkewitte, F., Shirazi, R. G., Schlue, F., Brecht, B., Rybkin, V. V., Stefszky, M., & Silberhorn, C. (2026). Bridging chemistry and Gaussian boson sampling: a photonic hierarchy of approximations for molecular vibronic spectra. Npj Quantum Information, 12(1), Article 89. https://doi.org/10.1038/s41534-026-01250-x' bibtex: '@article{Eickmann_Luo_Roiz_Lammers_Atzeni_Pandey_Lütkewitte_Shirazi_Schlue_Brecht_et al._2026, title={Bridging chemistry and Gaussian boson sampling: a photonic hierarchy of approximations for molecular vibronic spectra}, volume={12}, DOI={10.1038/s41534-026-01250-x}, number={189}, journal={npj Quantum Information}, publisher={Springer Science and Business Media LLC}, author={Eickmann, Jan-Lucas and Luo, Kai-Hong and Roiz, Mikhail and Lammers, Jonas and Atzeni, Simone and Pandey, Cheeranjiv and Lütkewitte, Florian and Shirazi, Reza G. and Schlue, Fabian and Brecht, Benjamin and et al.}, year={2026} }' chicago: 'Eickmann, Jan-Lucas, Kai-Hong Luo, Mikhail Roiz, Jonas Lammers, Simone Atzeni, Cheeranjiv Pandey, Florian Lütkewitte, et al. “Bridging Chemistry and Gaussian Boson Sampling: A Photonic Hierarchy of Approximations for Molecular Vibronic Spectra.” Npj Quantum Information 12, no. 1 (2026). https://doi.org/10.1038/s41534-026-01250-x.' ieee: 'J.-L. Eickmann et al., “Bridging chemistry and Gaussian boson sampling: a photonic hierarchy of approximations for molecular vibronic spectra,” npj Quantum Information, vol. 12, no. 1, Art. no. 89, 2026, doi: 10.1038/s41534-026-01250-x.' mla: 'Eickmann, Jan-Lucas, et al. “Bridging Chemistry and Gaussian Boson Sampling: A Photonic Hierarchy of Approximations for Molecular Vibronic Spectra.” Npj Quantum Information, vol. 12, no. 1, 89, Springer Science and Business Media LLC, 2026, doi:10.1038/s41534-026-01250-x.' short: J.-L. Eickmann, K.-H. Luo, M. Roiz, J. Lammers, S. Atzeni, C. Pandey, F. Lütkewitte, R.G. Shirazi, F. Schlue, B. Brecht, V.V. Rybkin, M. Stefszky, C. Silberhorn, Npj Quantum Information 12 (2026). date_created: 2026-06-12T08:14:35Z date_updated: 2026-06-12T08:28:02Z department: - _id: '288' - _id: '623' - _id: '15' doi: 10.1038/s41534-026-01250-x intvolume: ' 12' issue: '1' language: - iso: eng main_file_link: - open_access: '1' url: https://www.nature.com/articles/s41534-026-01250-x.pdf oa: '1' project: - _id: '191' name: 'PhoQuant: Photonische Quantencomputer - Quantencomputing Testplattform' publication: npj Quantum Information publication_identifier: issn: - 2056-6387 publication_status: published publisher: Springer Science and Business Media LLC related_material: link: - relation: research_data url: https://doi.org/10.5281/zenodo.18969354 status: public title: 'Bridging chemistry and Gaussian boson sampling: a photonic hierarchy of approximations for molecular vibronic spectra' type: journal_article user_id: '73665' volume: 12 year: '2026' ... --- _id: '66583' abstract: - lang: eng text: We introduce a method for determining the sensitivity of any given entangled two-photon absorption (ETPA) measurement. By modeling all signal and noise contributions to the measurement, we derive a single numerical value that describes the sensitivity of the ETPA measurement in Göppert-Mayer units. This allows us to directly compare vastly different experimental approaches and determine whether ETPA will be detectable under the given conditions. Therefore we can quantify the effect of any change to a given experimental apparatus and identify the ideal optimization pathway. article_number: '013718' article_type: original author: - first_name: René full_name: Pollmann, René id: '78890' last_name: Pollmann - first_name: Franz full_name: Roeder, Franz id: '88149' last_name: Roeder - first_name: Christine full_name: Silberhorn, Christine id: '26263' last_name: Silberhorn - first_name: Benjamin full_name: Brecht, Benjamin id: '27150' last_name: Brecht orcid: '0000-0003-4140-0556 ' citation: ama: Pollmann R, Roeder F, Silberhorn C, Brecht B. Limitations of entangled two-photon absorption detection. Physical Review A. 2026;114(1). doi:10.1103/qpb1-hk5l apa: Pollmann, R., Roeder, F., Silberhorn, C., & Brecht, B. (2026). Limitations of entangled two-photon absorption detection. Physical Review A, 114(1), Article 013718. https://doi.org/10.1103/qpb1-hk5l bibtex: '@article{Pollmann_Roeder_Silberhorn_Brecht_2026, title={Limitations of entangled two-photon absorption detection}, volume={114}, DOI={10.1103/qpb1-hk5l}, number={1013718}, journal={Physical Review A}, publisher={American Physical Society (APS)}, author={Pollmann, René and Roeder, Franz and Silberhorn, Christine and Brecht, Benjamin}, year={2026} }' chicago: Pollmann, René, Franz Roeder, Christine Silberhorn, and Benjamin Brecht. “Limitations of Entangled Two-Photon Absorption Detection.” Physical Review A 114, no. 1 (2026). https://doi.org/10.1103/qpb1-hk5l. ieee: 'R. Pollmann, F. Roeder, C. Silberhorn, and B. Brecht, “Limitations of entangled two-photon absorption detection,” Physical Review A, vol. 114, no. 1, Art. no. 013718, 2026, doi: 10.1103/qpb1-hk5l.' mla: Pollmann, René, et al. “Limitations of Entangled Two-Photon Absorption Detection.” Physical Review A, vol. 114, no. 1, 013718, American Physical Society (APS), 2026, doi:10.1103/qpb1-hk5l. short: R. Pollmann, F. Roeder, C. Silberhorn, B. Brecht, Physical Review A 114 (2026). date_created: 2026-07-24T10:53:18Z date_updated: 2026-07-24T11:00:08Z department: - _id: '623' - _id: '15' doi: 10.1103/qpb1-hk5l intvolume: ' 114' issue: '1' language: - iso: eng main_file_link: - open_access: '1' url: https://journals.aps.org/pra/abstract/10.1103/qpb1-hk5l oa: '1' publication: Physical Review A publication_identifier: issn: - 2469-9926 - 2469-9934 publication_status: published publisher: American Physical Society (APS) status: public title: Limitations of entangled two-photon absorption detection type: journal_article user_id: '78890' volume: 114 year: '2026' ... --- _id: '66741' abstract: - lang: eng text: "Abstract\r\n \r\n We study theoretically how high-gain effects affect the measurement outcome of visible signal spectra in undetected photon measurement schemes. We consider two interferometric configurations: firstly, the SU(1,1) interferometer where the idler incurs loss and additional dispersion in between two identical, lossless, squeezers; secondly, the induced coherence interferometer where the idler incurs loss and additional dispersion in between two identical, lossless, squeezers and where the second squeezer is seeded by the idler and a vacuum ancilla mode. Furthermore, we consider a distributed loss configuration where the idler incurs loss as it propagates in the nonlinear medium. Motivated by experimental evidence and due to the fact that broadband sources are ideal for these measurement schemes, we use the dispersive data of a third-order dispersion engineered integrated waveguide parametric down conversion (PDC) source presented in Roeder\r\n et al\r\n (2024 New J. Phys.\r\n 26\r\n \ 123025) to model the PDC spectra in the three configurations. For each configuration we consider the case of idler-only (i) absorption, (ii) additional dispersion, and (iii) the combined effects. We obtain results which outline the strength and weaknesses of the different configurations at different operation points.\r\n " article_number: '074509' author: - first_name: Martin full_name: Houde, Martin last_name: Houde - first_name: Franz full_name: Roeder, Franz id: '88149' last_name: Roeder - first_name: Christine full_name: Silberhorn, Christine id: '26263' last_name: Silberhorn - first_name: Benjamin full_name: Brecht, Benjamin id: '27150' last_name: Brecht orcid: '0000-0003-4140-0556 ' - first_name: Nicolás full_name: Quesada, Nicolás last_name: Quesada citation: ama: Houde M, Roeder F, Silberhorn C, Brecht B, Quesada N. High-gain effects in broadband continuous-wave parametric down conversion sources and measurements with undetected photons. New Journal of Physics. 2026;28(7). doi:10.1088/1367-2630/ae8692 apa: Houde, M., Roeder, F., Silberhorn, C., Brecht, B., & Quesada, N. (2026). High-gain effects in broadband continuous-wave parametric down conversion sources and measurements with undetected photons. New Journal of Physics, 28(7), Article 074509. https://doi.org/10.1088/1367-2630/ae8692 bibtex: '@article{Houde_Roeder_Silberhorn_Brecht_Quesada_2026, title={High-gain effects in broadband continuous-wave parametric down conversion sources and measurements with undetected photons}, volume={28}, DOI={10.1088/1367-2630/ae8692}, number={7074509}, journal={New Journal of Physics}, publisher={IOP Publishing}, author={Houde, Martin and Roeder, Franz and Silberhorn, Christine and Brecht, Benjamin and Quesada, Nicolás}, year={2026} }' chicago: Houde, Martin, Franz Roeder, Christine Silberhorn, Benjamin Brecht, and Nicolás Quesada. “High-Gain Effects in Broadband Continuous-Wave Parametric down Conversion Sources and Measurements with Undetected Photons.” New Journal of Physics 28, no. 7 (2026). https://doi.org/10.1088/1367-2630/ae8692. ieee: 'M. Houde, F. Roeder, C. Silberhorn, B. Brecht, and N. Quesada, “High-gain effects in broadband continuous-wave parametric down conversion sources and measurements with undetected photons,” New Journal of Physics, vol. 28, no. 7, Art. no. 074509, 2026, doi: 10.1088/1367-2630/ae8692.' mla: Houde, Martin, et al. “High-Gain Effects in Broadband Continuous-Wave Parametric down Conversion Sources and Measurements with Undetected Photons.” New Journal of Physics, vol. 28, no. 7, 074509, IOP Publishing, 2026, doi:10.1088/1367-2630/ae8692. short: M. Houde, F. Roeder, C. Silberhorn, B. Brecht, N. Quesada, New Journal of Physics 28 (2026). date_created: 2026-08-18T10:21:08Z date_updated: 2026-08-18T10:21:29Z department: - _id: '15' - _id: '623' - _id: '288' doi: 10.1088/1367-2630/ae8692 intvolume: ' 28' issue: '7' language: - iso: eng publication: New Journal of Physics publication_identifier: issn: - 1367-2630 publication_status: published publisher: IOP Publishing status: public title: High-gain effects in broadband continuous-wave parametric down conversion sources and measurements with undetected photons type: journal_article user_id: '27150' volume: 28 year: '2026' ... --- _id: '66740' abstract: - lang: eng text: "Abstract\r\n \r\n We theoretically compare the quantum Fisher information (QFI) for three configurations of absorption spectroscopy with undetected idler photons: an SU(1,1) interferometer with inter-source idler loss, an induced-coherence (IC) setup in which the idler partially seeds a second squeezer together with a vacuum ancilla, and a distributed-loss (DL) scheme with in-medium attenuation. We calculate the QFI as a function of parametric gain for both full and signal-only detection access. For losses below 99% and low to moderate gain, the SU(1,1) configuration provides the largest QFI. At high gain and intermediate loss, the IC scheme performs best, while under extreme attenuation (transmission\r\n \r\n \r\n \ \r\n \r\n \r\n \r\n \ <\r\n \r\n \ \r\n \r\n \ 1%) the DL model becomes optimal. These results delineate the measurement regimes in which each architecture is optimal in terms of information theory.\r\n " article_number: '035013' author: - first_name: Martin full_name: Houde, Martin last_name: Houde - first_name: Franz full_name: Roeder, Franz id: '88149' last_name: Roeder - first_name: Christine full_name: Silberhorn, Christine id: '26263' last_name: Silberhorn - first_name: Benjamin full_name: Brecht, Benjamin id: '27150' last_name: Brecht orcid: '0000-0003-4140-0556 ' - first_name: Nicolás full_name: Quesada, Nicolás last_name: Quesada citation: ama: 'Houde M, Roeder F, Silberhorn C, Brecht B, Quesada N. Quantum fisher information analysis for absorption measurements with undetected photons. Journal of Physics: Photonics. 2026;8(3). doi:10.1088/2515-7647/ae82a2' apa: 'Houde, M., Roeder, F., Silberhorn, C., Brecht, B., & Quesada, N. (2026). Quantum fisher information analysis for absorption measurements with undetected photons. Journal of Physics: Photonics, 8(3), Article 035013. https://doi.org/10.1088/2515-7647/ae82a2' bibtex: '@article{Houde_Roeder_Silberhorn_Brecht_Quesada_2026, title={Quantum fisher information analysis for absorption measurements with undetected photons}, volume={8}, DOI={10.1088/2515-7647/ae82a2}, number={3035013}, journal={Journal of Physics: Photonics}, publisher={IOP Publishing}, author={Houde, Martin and Roeder, Franz and Silberhorn, Christine and Brecht, Benjamin and Quesada, Nicolás}, year={2026} }' chicago: 'Houde, Martin, Franz Roeder, Christine Silberhorn, Benjamin Brecht, and Nicolás Quesada. “Quantum Fisher Information Analysis for Absorption Measurements with Undetected Photons.” Journal of Physics: Photonics 8, no. 3 (2026). https://doi.org/10.1088/2515-7647/ae82a2.' ieee: 'M. Houde, F. Roeder, C. Silberhorn, B. Brecht, and N. Quesada, “Quantum fisher information analysis for absorption measurements with undetected photons,” Journal of Physics: Photonics, vol. 8, no. 3, Art. no. 035013, 2026, doi: 10.1088/2515-7647/ae82a2.' mla: 'Houde, Martin, et al. “Quantum Fisher Information Analysis for Absorption Measurements with Undetected Photons.” Journal of Physics: Photonics, vol. 8, no. 3, 035013, IOP Publishing, 2026, doi:10.1088/2515-7647/ae82a2.' short: 'M. Houde, F. Roeder, C. Silberhorn, B. Brecht, N. Quesada, Journal of Physics: Photonics 8 (2026).' date_created: 2026-08-18T10:20:21Z date_updated: 2026-08-18T10:20:54Z department: - _id: '15' - _id: '623' - _id: '288' doi: 10.1088/2515-7647/ae82a2 intvolume: ' 8' issue: '3' language: - iso: eng publication: 'Journal of Physics: Photonics' publication_identifier: issn: - 2515-7647 publication_status: published publisher: IOP Publishing status: public title: Quantum fisher information analysis for absorption measurements with undetected photons type: journal_article user_id: '27150' volume: 8 year: '2026' ... --- _id: '66877' abstract: - lang: eng text: Integrated photon-pair sources, providing scalability solutions, are crucial for large-scale realizations of quantum photonic technologies. Their traditional fabrication techniques, such as etching, are often complex, require long development cycles, and are resource inefficient in case of fabrication imperfections or failures. The two-photon polymerization (2PP) technique can offer a rapid, efficient, and reproducible alternative for the fabrication of integrated photonic devices. Here, we demonstrate an integrated photon-pair source based on a 2PP-defined strip-loaded waveguide on a periodically poled thin-film lithium niobate (TFLN) platform. The device generates photon pairs through type-II spontaneous parametric down-conversion (SPDC), employing first-order quasi-phase matching (QPM) with TM-polarized excitation light. The device achieves an on-chip pair generation rate of 4.357 MHz and a coincidence-to-accidental ratio (CAR) of ∼404. To prove the flexibility and versatility of the fabrication technique, the waveguides were erased from the LN substrate and reprinted, reaching comparable performance. This work demonstrates the potential of 2PP as a rapid production technique for high-performance integrated photon-pair sources, offering a practical solution to the limitations of traditional fabrication techniques and showcasing both reproducibility of the fabrication and the reusability of the substrate. article_number: '29244' article_type: original author: - first_name: Muhamed A. full_name: Sewidan, Muhamed A. last_name: Sewidan - first_name: Alexandra full_name: Rittmeier, Alexandra last_name: Rittmeier - first_name: Laura full_name: Bollmers, Laura id: '61375' last_name: Bollmers - first_name: Silia full_name: Babel, Silia id: '63231' last_name: Babel orcid: https://orcid.org/0000-0002-1568-2580 - first_name: Elisavet full_name: Chatzizyrli, Elisavet last_name: Chatzizyrli - first_name: Juan S. S. full_name: Duran Gomez, Juan S. S. last_name: Duran Gomez - first_name: Laura full_name: Padberg, Laura id: '40300' last_name: Padberg - first_name: Christof full_name: Eigner, Christof id: '13244' last_name: Eigner orcid: https://orcid.org/0000-0002-5693-3083 - first_name: Christine full_name: Silberhorn, Christine id: '26263' last_name: Silberhorn - first_name: Douglas full_name: Bremner, Douglas last_name: Bremner - first_name: Andreas full_name: Wienke, Andreas last_name: Wienke - first_name: Dietmar full_name: Kracht, Dietmar last_name: Kracht - first_name: Moritz full_name: Hinkelmann, Moritz last_name: Hinkelmann - first_name: Michael full_name: Kues, Michael last_name: Kues citation: ama: Sewidan MA, Rittmeier A, Bollmers L, et al. High-performance photon-pair source using a two-photon-polymerized strip-loaded lithium niobate waveguide. Optics Express. 2026;34(16). doi:10.1364/oe.596879 apa: Sewidan, M. A., Rittmeier, A., Bollmers, L., Babel, S., Chatzizyrli, E., Duran Gomez, J. S. S., Padberg, L., Eigner, C., Silberhorn, C., Bremner, D., Wienke, A., Kracht, D., Hinkelmann, M., & Kues, M. (2026). High-performance photon-pair source using a two-photon-polymerized strip-loaded lithium niobate waveguide. Optics Express, 34(16), Article 29244. https://doi.org/10.1364/oe.596879 bibtex: '@article{Sewidan_Rittmeier_Bollmers_Babel_Chatzizyrli_Duran Gomez_Padberg_Eigner_Silberhorn_Bremner_et al._2026, title={High-performance photon-pair source using a two-photon-polymerized strip-loaded lithium niobate waveguide}, volume={34}, DOI={10.1364/oe.596879}, number={1629244}, journal={Optics Express}, publisher={Optica Publishing Group}, author={Sewidan, Muhamed A. and Rittmeier, Alexandra and Bollmers, Laura and Babel, Silia and Chatzizyrli, Elisavet and Duran Gomez, Juan S. S. and Padberg, Laura and Eigner, Christof and Silberhorn, Christine and Bremner, Douglas and et al.}, year={2026} }' chicago: Sewidan, Muhamed A., Alexandra Rittmeier, Laura Bollmers, Silia Babel, Elisavet Chatzizyrli, Juan S. S. Duran Gomez, Laura Padberg, et al. “High-Performance Photon-Pair Source Using a Two-Photon-Polymerized Strip-Loaded Lithium Niobate Waveguide.” Optics Express 34, no. 16 (2026). https://doi.org/10.1364/oe.596879. ieee: 'M. A. Sewidan et al., “High-performance photon-pair source using a two-photon-polymerized strip-loaded lithium niobate waveguide,” Optics Express, vol. 34, no. 16, Art. no. 29244, 2026, doi: 10.1364/oe.596879.' mla: Sewidan, Muhamed A., et al. “High-Performance Photon-Pair Source Using a Two-Photon-Polymerized Strip-Loaded Lithium Niobate Waveguide.” Optics Express, vol. 34, no. 16, 29244, Optica Publishing Group, 2026, doi:10.1364/oe.596879. short: M.A. Sewidan, A. Rittmeier, L. Bollmers, S. Babel, E. Chatzizyrli, J.S.S. Duran Gomez, L. Padberg, C. Eigner, C. Silberhorn, D. Bremner, A. Wienke, D. Kracht, M. Hinkelmann, M. Kues, Optics Express 34 (2026). date_created: 2026-08-31T12:02:48Z date_updated: 2026-08-31T12:11:43Z department: - _id: '15' - _id: '623' - _id: '288' doi: 10.1364/oe.596879 intvolume: ' 34' issue: '16' language: - iso: eng main_file_link: - open_access: '1' url: https://opg.optica.org/oe/fulltext.cfm?uri=oe-34-16-29244 oa: '1' publication: Optics Express publication_identifier: issn: - 1094-4087 publication_status: published publisher: Optica Publishing Group status: public title: High-performance photon-pair source using a two-photon-polymerized strip-loaded lithium niobate waveguide type: journal_article user_id: '63231' volume: 34 year: '2026' ... --- _id: '66939' abstract: - lang: eng text: "Many quantum optical applications in spectroscopy, communication and signal analysis rely on spectrally-engineered nonlinear optical interactions to target specific wavelengths or bandwidth. Here, in an established material platform like lithium niobate the achievable wavelength and bandwidth combinations are usually limited by the material’s dispersion and its birefringence. In this regard, mixed crystals of lithium niobate tantalate (LNT) promise a novel material platform, because they allow tuning the birefringence, which is central for type II phase matching devices. Crucially, LNT offers crystal compositions without any birefringence, which still retain their second-order optical nonlinearity. Despite recent progress in the growth and fabrication of LNT, so far no works have investigated the unique properties of LNT for use in electro-optics, nonlinear or quantum optics. In this study, we explore nonlinear optical devices based on LNT for broad- and narrowband nonlinear optical interactions based on recently measured Sellmeier coefficients. Most interestingly, we find that compositions without birefringence allow the design of broadband, degenerate type II phase matching sources spanning the whole near- to mid-infrared range by only changing the poling period and pump wavelength. Such devices are not easily realizable in pure lithium niobate or lithium tantalate. This could potentially allow for\tmore flexible light sources and nonlinear devices in quantum metrology, quantum spectroscopy and quantum communication." article_number: '2668' article_type: original author: - first_name: Franz full_name: Roeder, Franz id: '88149' last_name: Roeder - first_name: Michael full_name: Rüsing, Michael id: '22501' last_name: Rüsing orcid: 0000-0003-4682-4577 - first_name: Tobias full_name: Hehemann, Tobias last_name: Hehemann - first_name: Abira full_name: Gnanavel, Abira id: '81424' last_name: Gnanavel - first_name: Christof full_name: Eigner, Christof id: '13244' last_name: Eigner orcid: https://orcid.org/0000-0002-5693-3083 - first_name: Benjamin full_name: Brecht, Benjamin id: '27150' last_name: Brecht orcid: '0000-0003-4140-0556 ' - first_name: Mirco full_name: Imlau, Mirco last_name: Imlau - first_name: Christine full_name: Silberhorn, Christine id: '26263' last_name: Silberhorn citation: ama: 'Roeder F, Rüsing M, Hehemann T, et al. Lithium niobate tantalate mixed crystals: a versatile platform for nonlinear quantum processes. Optical Materials Express. 2026;16(8). doi:10.1364/ome.592892' apa: 'Roeder, F., Rüsing, M., Hehemann, T., Gnanavel, A., Eigner, C., Brecht, B., Imlau, M., & Silberhorn, C. (2026). Lithium niobate tantalate mixed crystals: a versatile platform for nonlinear quantum processes. Optical Materials Express, 16(8), Article 2668. https://doi.org/10.1364/ome.592892' bibtex: '@article{Roeder_Rüsing_Hehemann_Gnanavel_Eigner_Brecht_Imlau_Silberhorn_2026, title={Lithium niobate tantalate mixed crystals: a versatile platform for nonlinear quantum processes}, volume={16}, DOI={10.1364/ome.592892}, number={82668}, journal={Optical Materials Express}, publisher={Optica Publishing Group}, author={Roeder, Franz and Rüsing, Michael and Hehemann, Tobias and Gnanavel, Abira and Eigner, Christof and Brecht, Benjamin and Imlau, Mirco and Silberhorn, Christine}, year={2026} }' chicago: 'Roeder, Franz, Michael Rüsing, Tobias Hehemann, Abira Gnanavel, Christof Eigner, Benjamin Brecht, Mirco Imlau, and Christine Silberhorn. “Lithium Niobate Tantalate Mixed Crystals: A Versatile Platform for Nonlinear Quantum Processes.” Optical Materials Express 16, no. 8 (2026). https://doi.org/10.1364/ome.592892.' ieee: 'F. Roeder et al., “Lithium niobate tantalate mixed crystals: a versatile platform for nonlinear quantum processes,” Optical Materials Express, vol. 16, no. 8, Art. no. 2668, 2026, doi: 10.1364/ome.592892.' mla: 'Roeder, Franz, et al. “Lithium Niobate Tantalate Mixed Crystals: A Versatile Platform for Nonlinear Quantum Processes.” Optical Materials Express, vol. 16, no. 8, 2668, Optica Publishing Group, 2026, doi:10.1364/ome.592892.' short: F. Roeder, M. Rüsing, T. Hehemann, A. Gnanavel, C. Eigner, B. Brecht, M. Imlau, C. Silberhorn, Optical Materials Express 16 (2026). date_created: 2026-09-02T11:53:45Z date_updated: 2026-09-02T13:35:22Z department: - _id: '288' - _id: '623' - _id: '15' doi: 10.1364/ome.592892 funded_apc: '1' intvolume: ' 16' issue: '8' language: - iso: eng main_file_link: - open_access: '1' url: https://doi.org/10.1364/OME.592892 oa: '1' publication: Optical Materials Express publication_identifier: issn: - 2159-3930 publication_status: published publisher: Optica Publishing Group quality_controlled: '1' status: public title: 'Lithium niobate tantalate mixed crystals: a versatile platform for nonlinear quantum processes' type: journal_article user_id: '22501' volume: 16 year: '2026' ... --- _id: '65359' abstract: - lang: eng text: Lithium niobate sees widespread use in nonlinear and quantum optical devices, such as for sum- and difference-frequency generation or spontaneous parametric downconversion. In lithium niobate waveguides, nonlinear optical processes are often limited by the so-called photorefractive effect, which limits the maximum input or output powers and impacts the nonlinear spectral response. Therefore, strategies for the management of photorefractive damage are a key consideration in device design. Usually, the photorefractive damage threshold, i.e., the maximal permissible operating power, can be increased by high-temperature operation of devices. This approach, however, is not applicable in cryogenic environments, which may be required for specialized applications. To better understand the impact of photorefraction in nonlinear optical applications, we study the impact of photorefraction on the phase-matching spectra of two nonlinear-optical sum-frequency generation experiments at (1) high temperatures and (2) cryogenic temperatures. Furthermore, we present an approach to reduce the impact of photorefraction, which is compatible with cryogenic operation. This comprises an auxiliary light source, propagating in the same waveguide, which is used to restore phase-matching spectra impacted by photorefraction, as well as reduce pyroelectric effects. Our work provides an alternative route to photorefraction management applicable to cryogenic environments, as well as in situations with tight energy budgets, such as space applications. article_number: '133105' author: - first_name: Nina Amelie full_name: Lange, Nina Amelie id: '56843' last_name: Lange orcid: 0000-0001-6624-7098 - first_name: René full_name: Pollmann, René id: '78890' last_name: Pollmann - first_name: Michael full_name: Rüsing, Michael id: '22501' last_name: Rüsing orcid: 0000-0003-4682-4577 - first_name: Michael full_name: Stefszky, Michael id: '42777' last_name: Stefszky - first_name: Maximilian full_name: Protte, Maximilian id: '46170' last_name: Protte - first_name: Raimund full_name: Ricken, Raimund last_name: Ricken - first_name: Laura full_name: Padberg, Laura id: '40300' last_name: Padberg - first_name: Christof full_name: Eigner, Christof id: '13244' last_name: Eigner orcid: https://orcid.org/0000-0002-5693-3083 - first_name: Tim full_name: Bartley, Tim last_name: Bartley - first_name: Christine full_name: Silberhorn, Christine id: '26263' last_name: Silberhorn citation: ama: 'Lange NA, Pollmann R, Rüsing M, et al. Photorefraction management in lithium niobate waveguides: High-temperature vs cryogenic solutions. Journal of Applied Physics. 2026;139(13). doi:10.1063/5.0324002' apa: 'Lange, N. A., Pollmann, R., Rüsing, M., Stefszky, M., Protte, M., Ricken, R., Padberg, L., Eigner, C., Bartley, T., & Silberhorn, C. (2026). Photorefraction management in lithium niobate waveguides: High-temperature vs cryogenic solutions. Journal of Applied Physics, 139(13), Article 133105. https://doi.org/10.1063/5.0324002' bibtex: '@article{Lange_Pollmann_Rüsing_Stefszky_Protte_Ricken_Padberg_Eigner_Bartley_Silberhorn_2026, title={Photorefraction management in lithium niobate waveguides: High-temperature vs cryogenic solutions}, volume={139}, DOI={10.1063/5.0324002}, number={13133105}, journal={Journal of Applied Physics}, publisher={AIP Publishing}, author={Lange, Nina Amelie and Pollmann, René and Rüsing, Michael and Stefszky, Michael and Protte, Maximilian and Ricken, Raimund and Padberg, Laura and Eigner, Christof and Bartley, Tim and Silberhorn, Christine}, year={2026} }' chicago: 'Lange, Nina Amelie, René Pollmann, Michael Rüsing, Michael Stefszky, Maximilian Protte, Raimund Ricken, Laura Padberg, Christof Eigner, Tim Bartley, and Christine Silberhorn. “Photorefraction Management in Lithium Niobate Waveguides: High-Temperature vs Cryogenic Solutions.” Journal of Applied Physics 139, no. 13 (2026). https://doi.org/10.1063/5.0324002.' ieee: 'N. A. Lange et al., “Photorefraction management in lithium niobate waveguides: High-temperature vs cryogenic solutions,” Journal of Applied Physics, vol. 139, no. 13, Art. no. 133105, 2026, doi: 10.1063/5.0324002.' mla: 'Lange, Nina Amelie, et al. “Photorefraction Management in Lithium Niobate Waveguides: High-Temperature vs Cryogenic Solutions.” Journal of Applied Physics, vol. 139, no. 13, 133105, AIP Publishing, 2026, doi:10.1063/5.0324002.' short: N.A. Lange, R. Pollmann, M. Rüsing, M. Stefszky, M. Protte, R. Ricken, L. Padberg, C. Eigner, T. Bartley, C. Silberhorn, Journal of Applied Physics 139 (2026). date_created: 2026-04-07T08:41:07Z date_updated: 2026-09-02T12:06:14Z doi: 10.1063/5.0324002 intvolume: ' 139' issue: '13' language: - iso: eng publication: Journal of Applied Physics publication_identifier: issn: - 0021-8979 - 1089-7550 publication_status: published publisher: AIP Publishing status: public title: 'Photorefraction management in lithium niobate waveguides: High-temperature vs cryogenic solutions' type: journal_article user_id: '22501' volume: 139 year: '2026' ... --- _id: '66094' abstract: - lang: eng text: The two-qubit controlled-not (C-NOT) gate is an essential component for gate-based quantum circuits. In fact, its operation, combined with single qubit rotations allows to realise any quantum circuit. Several strategies have been adopted in order to build quantum gates. Among them, photonics offers the dual advantage of excellent isolation from the environment and ease of manipulation at the single qubit level. Here we adopt a scalable time-multiplexed approach in order to build a fully reconfigurable architecture capable of implementing a post-selected C-NOT gate with a fidelity of (93.8 ± 1.4)%. We then show how our time-multiplexed platform can be employed to combine a C-NOT and a single qubit gate in order to generate the four Bell states. article_number: '5683' article_type: original author: - first_name: Federico full_name: Pegoraro, Federico id: '88928' last_name: Pegoraro - first_name: Philip full_name: Held, Philip id: '68236' last_name: Held - first_name: Jonas full_name: Lammers, Jonas last_name: Lammers - 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 citation: ama: Pegoraro F, Held P, Lammers J, Brecht B, Silberhorn C. Demonstration of a quantum C-NOT gate in a time-multiplexed fully reconfigurable photonic processor. Nature Communications. 2026;17(1). doi:10.1038/s41467-026-74861-9 apa: Pegoraro, F., Held, P., Lammers, J., Brecht, B., & Silberhorn, C. (2026). Demonstration of a quantum C-NOT gate in a time-multiplexed fully reconfigurable photonic processor. Nature Communications, 17(1), Article 5683. https://doi.org/10.1038/s41467-026-74861-9 bibtex: '@article{Pegoraro_Held_Lammers_Brecht_Silberhorn_2026, title={Demonstration of a quantum C-NOT gate in a time-multiplexed fully reconfigurable photonic processor}, volume={17}, DOI={10.1038/s41467-026-74861-9}, number={15683}, journal={Nature Communications}, publisher={Springer Science and Business Media LLC}, author={Pegoraro, Federico and Held, Philip and Lammers, Jonas and Brecht, Benjamin and Silberhorn, Christine}, year={2026} }' chicago: Pegoraro, Federico, Philip Held, Jonas Lammers, Benjamin Brecht, and Christine Silberhorn. “Demonstration of a Quantum C-NOT Gate in a Time-Multiplexed Fully Reconfigurable Photonic Processor.” Nature Communications 17, no. 1 (2026). https://doi.org/10.1038/s41467-026-74861-9. ieee: 'F. Pegoraro, P. Held, J. Lammers, B. Brecht, and C. Silberhorn, “Demonstration of a quantum C-NOT gate in a time-multiplexed fully reconfigurable photonic processor,” Nature Communications, vol. 17, no. 1, Art. no. 5683, 2026, doi: 10.1038/s41467-026-74861-9.' mla: Pegoraro, Federico, et al. “Demonstration of a Quantum C-NOT Gate in a Time-Multiplexed Fully Reconfigurable Photonic Processor.” Nature Communications, vol. 17, no. 1, 5683, Springer Science and Business Media LLC, 2026, doi:10.1038/s41467-026-74861-9. short: F. Pegoraro, P. Held, J. Lammers, B. Brecht, C. Silberhorn, Nature Communications 17 (2026). date_created: 2026-07-01T07:47:15Z date_updated: 2026-07-01T08:15:21Z department: - _id: '288' - _id: '623' - _id: '15' doi: 10.1038/s41467-026-74861-9 intvolume: ' 17' issue: '1' keyword: - Photonic Quantum Computing - Time-multiplexing - Quantum Information language: - iso: eng main_file_link: - open_access: '1' url: https://www.nature.com/articles/s41467-026-74861-9 oa: '1' publication: Nature Communications publication_identifier: issn: - 2041-1723 publication_status: published publisher: Springer Science and Business Media LLC related_material: link: - description: Supplementary notes to the main article relation: supplementary_material url: https://static-content.springer.com/esm/art%3A10.1038%2Fs41467-026-74861-9/MediaObjects/41467_2026_74861_MOESM1_ESM.pdf - description: Datasets and code relation: supplementary_material url: https://doi.org/10.5281/zenodo.20396394 status: public title: Demonstration of a quantum C-NOT gate in a time-multiplexed fully reconfigurable photonic processor type: journal_article user_id: '88928' volume: 17 year: '2026' ... --- _id: '62639' author: - first_name: Stephan full_name: Kruse, Stephan id: '38254' last_name: Kruse - first_name: Christine full_name: Silberhorn, Christine id: '26263' last_name: Silberhorn - first_name: Benjamin full_name: Brecht, Benjamin id: '27150' last_name: Brecht orcid: '0000-0003-4140-0556 ' - first_name: Tobias full_name: Schwabe, Tobias id: '39217' last_name: Schwabe citation: ama: Kruse S, Silberhorn C, Brecht B, Schwabe T. Optisch basierter Digital-Analog-Umsetzer. Published online 2025. apa: Kruse, S., Silberhorn, C., Brecht, B., & Schwabe, T. (2025). Optisch basierter Digital-Analog-Umsetzer. bibtex: '@article{Kruse_Silberhorn_Brecht_Schwabe_2025, title={Optisch basierter Digital-Analog-Umsetzer}, author={Kruse, Stephan and Silberhorn, Christine and Brecht, Benjamin and Schwabe, Tobias}, year={2025} }' chicago: Kruse, Stephan, Christine Silberhorn, Benjamin Brecht, and Tobias Schwabe. “Optisch Basierter Digital-Analog-Umsetzer,” 2025. ieee: S. Kruse, C. Silberhorn, B. Brecht, and T. Schwabe, “Optisch basierter Digital-Analog-Umsetzer.” 2025. mla: Kruse, Stephan, et al. Optisch Basierter Digital-Analog-Umsetzer. 2025. short: S. Kruse, C. Silberhorn, B. Brecht, T. Schwabe, (2025). date_created: 2025-11-27T07:00:50Z date_updated: 2025-11-27T07:07:16Z department: - _id: '58' - _id: '623' - _id: '288' ipc: H03M 1/66 ipn: DE102023212604B3 publication_date: 2025-01-23 status: public title: Optisch basierter Digital-Analog-Umsetzer type: patent user_id: '38254' year: '2025' ... --- _id: '62911' abstract: - lang: eng text: In this paper, we theoretically study the spectral and temporal properties of pulsed spontaneous parametric down-conversion (SPDC) generated in lossy waveguides. Our theoretical approach is based on the formalism of Gaussian states and the Langevin equation, which is elaborated for weak parametric down-conversion and photon-number-unresolved click detection. Using the example of frequency-degenerate type-II SPDC generated under the pump-idler group-velocity-matching condition, we show how the joint-spectral intensity, mode structure, normalized second-order correlation function, and Hong-Ou-Mandel interference pattern depend on internal losses of the SPDC process. We found that the joint-spectral intensity is almost insensitive to internal losses, while the second-order correlation function shows a strong dependence on them, being different for the signal and idler beams in the presence of internal losses. Based on the sensitivity of the normalized second-order correlation function, we show how its measurement can be used to experimentally determine internal losses. article_number: '033122' author: - first_name: Denis A. full_name: Kopylov, Denis A. last_name: Kopylov - first_name: Michael full_name: Stefszky, Michael id: '42777' last_name: Stefszky - first_name: Torsten full_name: Meier, Torsten id: '344' last_name: Meier orcid: 0000-0001-8864-2072 - first_name: Christine full_name: Silberhorn, Christine id: '26263' last_name: Silberhorn - first_name: Polina R. full_name: Sharapova, Polina R. id: '60286' last_name: Sharapova citation: ama: 'Kopylov DA, Stefszky M, Meier T, Silberhorn C, Sharapova PR. Spectral and temporal properties of type-II parametric down-conversion: The impact of losses during state generation. Physical Review Research. 2025;7(3). doi:10.1103/zp72-7qwl' apa: 'Kopylov, D. A., Stefszky, M., Meier, T., Silberhorn, C., & Sharapova, P. R. (2025). Spectral and temporal properties of type-II parametric down-conversion: The impact of losses during state generation. Physical Review Research, 7(3), Article 033122. https://doi.org/10.1103/zp72-7qwl' bibtex: '@article{Kopylov_Stefszky_Meier_Silberhorn_Sharapova_2025, title={Spectral and temporal properties of type-II parametric down-conversion: The impact of losses during state generation}, volume={7}, DOI={10.1103/zp72-7qwl}, number={3033122}, journal={Physical Review Research}, publisher={American Physical Society (APS)}, author={Kopylov, Denis A. and Stefszky, Michael and Meier, Torsten and Silberhorn, Christine and Sharapova, Polina R.}, year={2025} }' chicago: 'Kopylov, Denis A., Michael Stefszky, Torsten Meier, Christine Silberhorn, and Polina R. Sharapova. “Spectral and Temporal Properties of Type-II Parametric down-Conversion: The Impact of Losses during State Generation.” Physical Review Research 7, no. 3 (2025). https://doi.org/10.1103/zp72-7qwl.' ieee: 'D. A. Kopylov, M. Stefszky, T. Meier, C. Silberhorn, and P. R. Sharapova, “Spectral and temporal properties of type-II parametric down-conversion: The impact of losses during state generation,” Physical Review Research, vol. 7, no. 3, Art. no. 033122, 2025, doi: 10.1103/zp72-7qwl.' mla: 'Kopylov, Denis A., et al. “Spectral and Temporal Properties of Type-II Parametric down-Conversion: The Impact of Losses during State Generation.” Physical Review Research, vol. 7, no. 3, 033122, American Physical Society (APS), 2025, doi:10.1103/zp72-7qwl.' short: D.A. Kopylov, M. Stefszky, T. Meier, C. Silberhorn, P.R. Sharapova, Physical Review Research 7 (2025). date_created: 2025-12-05T09:33:36Z date_updated: 2025-12-05T09:55:22Z department: - _id: '15' - _id: '569' - _id: '170' - _id: '293' - _id: '288' - _id: '230' - _id: '623' - _id: '429' - _id: '35' doi: 10.1103/zp72-7qwl intvolume: ' 7' issue: '3' language: - iso: eng project: - _id: '266' name: 'PhoQC: Photonisches Quantencomputing' - _id: '53' name: 'TRR 142: Maßgeschneiderte nichtlineare Photonik: Von grundlegenden Konzepten zu funktionellen Strukturen' - _id: '56' name: TRR 142 - Project Area C - _id: '174' name: 'TRR 142 ; TP: C10: Erzeugung und Charakterisierung von Quantenlicht in nichtlinearen Systemen: Eine theoretische Analyse' publication: Physical Review Research publication_identifier: issn: - 2643-1564 publication_status: published publisher: American Physical Society (APS) status: public title: 'Spectral and temporal properties of type-II parametric down-conversion: The impact of losses during state generation' type: journal_article user_id: '16199' volume: 7 year: '2025' ... --- _id: '62269' abstract: - lang: eng text: The titanium in-diffused lithium niobate waveguide platform is well-established for reliable prototyping and packaging of many quantum photonic components at room temperature. Nevertheless, compatibility with certain quantum light sources and superconducting detectors requires operation under cryogenic conditions. We characterize alterations in phase-matching and mode guiding of a non-degenerate spontaneous parametric down-conversion process emitting around 1556 nm and 950 nm, under cryogenic conditions. Despite the effects of pyroelectricity and photorefraction, the spectral properties match our theoretical model. Nevertheless, these effects cause small but significant variations within and between cooling cycles. These measurements provide a first benchmark against which other nonlinear photonic integration platforms, such as thin-film lithium niobate, can be compared. article_number: '50451' article_type: original author: - first_name: Nina Amelie full_name: Lange, Nina Amelie id: '56843' last_name: Lange orcid: 0000-0001-6624-7098 - first_name: Sebastian full_name: Lengeling, Sebastian id: '44373' last_name: Lengeling - first_name: Philipp full_name: Mues, Philipp id: '49772' last_name: Mues orcid: 0000-0003-0643-7636 - first_name: Viktor full_name: Quiring, Viktor last_name: Quiring - first_name: Werner full_name: Ridder, Werner id: '63574' last_name: Ridder - first_name: Christof full_name: Eigner, Christof id: '13244' last_name: Eigner orcid: https://orcid.org/0000-0002-5693-3083 - first_name: Harald full_name: Herrmann, Harald id: '216' last_name: Herrmann - first_name: Christine full_name: Silberhorn, Christine id: '26263' last_name: Silberhorn - first_name: Tim full_name: Bartley, Tim id: '49683' last_name: Bartley citation: ama: Lange NA, Lengeling S, Mues P, et al. Widely non-degenerate nonlinear frequency conversion in cryogenic titanium in-diffused lithium niobate waveguides. Optics Express. 2025;33(24). doi:10.1364/oe.578108 apa: Lange, N. A., Lengeling, S., Mues, P., Quiring, V., Ridder, W., Eigner, C., Herrmann, H., Silberhorn, C., & Bartley, T. (2025). Widely non-degenerate nonlinear frequency conversion in cryogenic titanium in-diffused lithium niobate waveguides. Optics Express, 33(24), Article 50451. https://doi.org/10.1364/oe.578108 bibtex: '@article{Lange_Lengeling_Mues_Quiring_Ridder_Eigner_Herrmann_Silberhorn_Bartley_2025, title={Widely non-degenerate nonlinear frequency conversion in cryogenic titanium in-diffused lithium niobate waveguides}, volume={33}, DOI={10.1364/oe.578108}, number={2450451}, journal={Optics Express}, publisher={Optica Publishing Group}, author={Lange, Nina Amelie and Lengeling, Sebastian and Mues, Philipp and Quiring, Viktor and Ridder, Werner and Eigner, Christof and Herrmann, Harald and Silberhorn, Christine and Bartley, Tim}, year={2025} }' chicago: Lange, Nina Amelie, Sebastian Lengeling, Philipp Mues, Viktor Quiring, Werner Ridder, Christof Eigner, Harald Herrmann, Christine Silberhorn, and Tim Bartley. “Widely Non-Degenerate Nonlinear Frequency Conversion in Cryogenic Titanium in-Diffused Lithium Niobate Waveguides.” Optics Express 33, no. 24 (2025). https://doi.org/10.1364/oe.578108. ieee: 'N. A. Lange et al., “Widely non-degenerate nonlinear frequency conversion in cryogenic titanium in-diffused lithium niobate waveguides,” Optics Express, vol. 33, no. 24, Art. no. 50451, 2025, doi: 10.1364/oe.578108.' mla: Lange, Nina Amelie, et al. “Widely Non-Degenerate Nonlinear Frequency Conversion in Cryogenic Titanium in-Diffused Lithium Niobate Waveguides.” Optics Express, vol. 33, no. 24, 50451, Optica Publishing Group, 2025, doi:10.1364/oe.578108. short: N.A. Lange, S. Lengeling, P. Mues, V. Quiring, W. Ridder, C. Eigner, H. Herrmann, C. Silberhorn, T. Bartley, Optics Express 33 (2025). date_created: 2025-11-20T10:35:35Z date_updated: 2025-12-12T12:13:45Z department: - _id: '15' - _id: '623' - _id: '288' doi: 10.1364/oe.578108 intvolume: ' 33' issue: '24' language: - iso: eng main_file_link: - open_access: '1' oa: '1' project: - _id: '171' name: 'TRR 142; TP C07: Hohlraum-verstärkte Parametrische Fluoreszenz mit zeitlicher Filterung unter Verwendung integrierter supraleitender Detektoren' publication: Optics Express publication_identifier: issn: - 1094-4087 publication_status: published publisher: Optica Publishing Group status: public title: Widely non-degenerate nonlinear frequency conversion in cryogenic titanium in-diffused lithium niobate waveguides type: journal_article user_id: '49683' volume: 33 year: '2025' ... --- _id: '60466' author: - first_name: Julian full_name: Brockmeier, Julian id: '44807' last_name: Brockmeier - first_name: Timon full_name: Schapeler, Timon id: '55629' last_name: Schapeler orcid: 0000-0001-7652-1716 - first_name: Nina Amelie full_name: Lange, Nina Amelie id: '56843' last_name: Lange orcid: 0000-0001-6624-7098 - first_name: Jan Philipp full_name: Höpker, Jan Philipp id: '33913' last_name: Höpker - first_name: Harald full_name: Herrmann, Harald id: '216' last_name: Herrmann - first_name: Christine full_name: Silberhorn, Christine id: '26263' last_name: Silberhorn - first_name: Tim full_name: Bartley, Tim id: '49683' last_name: Bartley citation: ama: Brockmeier J, Schapeler T, Lange NA, et al. Harnessing temporal dispersion for integrated pump filtering in spontaneous heralded single-photon generation processes. New Journal of Physics. Published online 2025. doi:10.1088/1367-2630/ade46c apa: Brockmeier, J., Schapeler, T., Lange, N. A., Höpker, J. P., Herrmann, H., Silberhorn, C., & Bartley, T. (2025). Harnessing temporal dispersion for integrated pump filtering in spontaneous heralded single-photon generation processes. New Journal of Physics. https://doi.org/10.1088/1367-2630/ade46c bibtex: '@article{Brockmeier_Schapeler_Lange_Höpker_Herrmann_Silberhorn_Bartley_2025, title={Harnessing temporal dispersion for integrated pump filtering in spontaneous heralded single-photon generation processes}, DOI={10.1088/1367-2630/ade46c}, journal={New Journal of Physics}, author={Brockmeier, Julian and Schapeler, Timon and Lange, Nina Amelie and Höpker, Jan Philipp and Herrmann, Harald and Silberhorn, Christine and Bartley, Tim}, year={2025} }' chicago: Brockmeier, Julian, Timon Schapeler, Nina Amelie Lange, Jan Philipp Höpker, Harald Herrmann, Christine Silberhorn, and Tim Bartley. “Harnessing Temporal Dispersion for Integrated Pump Filtering in Spontaneous Heralded Single-Photon Generation Processes.” New Journal of Physics, 2025. https://doi.org/10.1088/1367-2630/ade46c. ieee: 'J. Brockmeier et al., “Harnessing temporal dispersion for integrated pump filtering in spontaneous heralded single-photon generation processes,” New Journal of Physics, 2025, doi: 10.1088/1367-2630/ade46c.' mla: Brockmeier, Julian, et al. “Harnessing Temporal Dispersion for Integrated Pump Filtering in Spontaneous Heralded Single-Photon Generation Processes.” New Journal of Physics, 2025, doi:10.1088/1367-2630/ade46c. short: J. Brockmeier, T. Schapeler, N.A. Lange, J.P. Höpker, H. Herrmann, C. Silberhorn, T. Bartley, New Journal of Physics (2025). date_created: 2025-06-30T08:58:37Z date_updated: 2025-12-15T09:21:29Z department: - _id: '15' - _id: '623' doi: 10.1088/1367-2630/ade46c language: - iso: eng main_file_link: - open_access: '1' oa: '1' project: - _id: '171' name: 'TRR 142; TP C07: Hohlraum-verstärkte Parametrische Fluoreszenz mit zeitlicher Filterung unter Verwendung integrierter supraleitender Detektoren' publication: New Journal of Physics status: public title: Harnessing temporal dispersion for integrated pump filtering in spontaneous heralded single-photon generation processes type: journal_article user_id: '56843' year: '2025' ... --- _id: '63192' abstract: - lang: eng text: Lithium niobate (LiNbO3) is a widely used material with several desirable physical properties, such as high second-order nonlinear optical and strong electro-optical effects. Thus LiNbO3 is used for various applications such as electro-optic modulation or nonlinear frequency conversion and mixing. But LiNbO3 also exhibits a strong photorefractive effect, which limits the intensity of the optical fields involved. Various approaches to reduce the photorefractive effect have been investigated, such as increasing the temperature, doping the crystal or using different waveguide designs in LiNbO3. Here, we present an analysis of the approach to increase the photorefractive damage threshold by using different waveguide designs. Contrary to previous claims and investigations, our SHG measurements revealed no significant difference in resistance to photorefractive damage when comparing conventional Ti-doped channel waveguides and Ti-doped diced ridge waveguides in LiNbO3. Furthermore, we have investigated the effect of photorefractive cleaning and curing using a light field at 532 nm. Here, we observe a reduction in the photorefractive effect at room temperature during and after SHG measurements, which is an easy alternative to conventional approaches. article_number: '114260' article_type: original author: - first_name: Michelle full_name: Kirsch, Michelle id: '69553' last_name: Kirsch - first_name: Christian full_name: Kießler, Christian id: '44252' last_name: Kießler - first_name: Sebastian full_name: Lengeling, Sebastian id: '44373' last_name: Lengeling - first_name: Michael full_name: Stefszky, Michael id: '42777' last_name: Stefszky - first_name: Christof full_name: Eigner, Christof id: '13244' last_name: Eigner orcid: https://orcid.org/0000-0002-5693-3083 - first_name: Harald full_name: Herrmann, Harald id: '216' last_name: Herrmann - first_name: Christine full_name: Silberhorn, Christine id: '26263' last_name: Silberhorn citation: ama: Kirsch M, Kießler C, Lengeling S, et al. Photorefraction and in-situ optical cleaning in various types of LiNbO3 waveguides. Optics & Laser Technology. 2025;193. doi:10.1016/j.optlastec.2025.114260 apa: Kirsch, M., Kießler, C., Lengeling, S., Stefszky, M., Eigner, C., Herrmann, H., & Silberhorn, C. (2025). Photorefraction and in-situ optical cleaning in various types of LiNbO3 waveguides. Optics & Laser Technology, 193, Article 114260. https://doi.org/10.1016/j.optlastec.2025.114260 bibtex: '@article{Kirsch_Kießler_Lengeling_Stefszky_Eigner_Herrmann_Silberhorn_2025, title={Photorefraction and in-situ optical cleaning in various types of LiNbO3 waveguides}, volume={193}, DOI={10.1016/j.optlastec.2025.114260}, number={114260}, journal={Optics & Laser Technology}, publisher={Elsevier BV}, author={Kirsch, Michelle and Kießler, Christian and Lengeling, Sebastian and Stefszky, Michael and Eigner, Christof and Herrmann, Harald and Silberhorn, Christine}, year={2025} }' chicago: Kirsch, Michelle, Christian Kießler, Sebastian Lengeling, Michael Stefszky, Christof Eigner, Harald Herrmann, and Christine Silberhorn. “Photorefraction and In-Situ Optical Cleaning in Various Types of LiNbO3 Waveguides.” Optics & Laser Technology 193 (2025). https://doi.org/10.1016/j.optlastec.2025.114260. ieee: 'M. Kirsch et al., “Photorefraction and in-situ optical cleaning in various types of LiNbO3 waveguides,” Optics & Laser Technology, vol. 193, Art. no. 114260, 2025, doi: 10.1016/j.optlastec.2025.114260.' mla: Kirsch, Michelle, et al. “Photorefraction and In-Situ Optical Cleaning in Various Types of LiNbO3 Waveguides.” Optics & Laser Technology, vol. 193, 114260, Elsevier BV, 2025, doi:10.1016/j.optlastec.2025.114260. short: M. Kirsch, C. Kießler, S. Lengeling, M. Stefszky, C. Eigner, H. Herrmann, C. Silberhorn, Optics & Laser Technology 193 (2025). date_created: 2025-12-18T08:17:57Z date_updated: 2025-12-18T08:27:13Z department: - _id: '288' - _id: '623' - _id: '15' doi: 10.1016/j.optlastec.2025.114260 intvolume: ' 193' language: - iso: eng main_file_link: - open_access: '1' url: https://www.sciencedirect.com/science/article/pii/S0030399225018511?via%3Dihub oa: '1' publication: Optics & Laser Technology publication_identifier: issn: - 0030-3992 publication_status: published publisher: Elsevier BV quality_controlled: '1' status: public title: Photorefraction and in-situ optical cleaning in various types of LiNbO3 waveguides type: journal_article user_id: '69553' volume: 193 year: '2025' ... --- _id: '63213' abstract: - lang: eng text: 'Quantum uncertainty relations impose fundamental limits on the joint knowledge that can be acquired from complementary observables: Perfect knowledge of a quantum state in one basis implies maximal indetermination in all other mutually unbiased bases (MUBs). Uncertainty relations derived from joint properties of the MUBs are generally assumed to be uniform, irrespective of the specific observables chosen within a set. In this work, we demonstrate instead that the uncertainty relations can depend on the choice of observables. Through both experimental observation and numerical methods, we show that selecting different sets of three MUBs in a five-dimensional quantum system results in distinct uncertainty bounds, i.e., in varying degrees of complementarity, in terms of both entropy and variance.' article_number: '033152' article_type: original author: - first_name: Laura Maria full_name: Serino, Laura Maria id: '88242' last_name: Serino - first_name: Giovanni full_name: Chesi, Giovanni last_name: Chesi - first_name: Benjamin full_name: Brecht, Benjamin id: '27150' last_name: Brecht orcid: '0000-0003-4140-0556 ' - first_name: Lorenzo full_name: Maccone, Lorenzo last_name: Maccone - first_name: Chiara full_name: Macchiavello, Chiara last_name: Macchiavello - first_name: Christine full_name: Silberhorn, Christine id: '26263' last_name: Silberhorn citation: ama: 'Serino LM, Chesi G, Brecht B, Maccone L, Macchiavello C, Silberhorn C. Complementarity-based complementarity: The choice of mutually unbiased observables shapes quantum uncertainty relations. Physical Review Research. 2025;7(3). doi:10.1103/v24q-sl6n' apa: 'Serino, L. M., Chesi, G., Brecht, B., Maccone, L., Macchiavello, C., & Silberhorn, C. (2025). Complementarity-based complementarity: The choice of mutually unbiased observables shapes quantum uncertainty relations. Physical Review Research, 7(3), Article 033152. https://doi.org/10.1103/v24q-sl6n' bibtex: '@article{Serino_Chesi_Brecht_Maccone_Macchiavello_Silberhorn_2025, title={Complementarity-based complementarity: The choice of mutually unbiased observables shapes quantum uncertainty relations}, volume={7}, DOI={10.1103/v24q-sl6n}, number={3033152}, journal={Physical Review Research}, publisher={American Physical Society (APS)}, author={Serino, Laura Maria and Chesi, Giovanni and Brecht, Benjamin and Maccone, Lorenzo and Macchiavello, Chiara and Silberhorn, Christine}, year={2025} }' chicago: 'Serino, Laura Maria, Giovanni Chesi, Benjamin Brecht, Lorenzo Maccone, Chiara Macchiavello, and Christine Silberhorn. “Complementarity-Based Complementarity: The Choice of Mutually Unbiased Observables Shapes Quantum Uncertainty Relations.” Physical Review Research 7, no. 3 (2025). https://doi.org/10.1103/v24q-sl6n.' ieee: 'L. M. Serino, G. Chesi, B. Brecht, L. Maccone, C. Macchiavello, and C. Silberhorn, “Complementarity-based complementarity: The choice of mutually unbiased observables shapes quantum uncertainty relations,” Physical Review Research, vol. 7, no. 3, Art. no. 033152, 2025, doi: 10.1103/v24q-sl6n.' mla: 'Serino, Laura Maria, et al. “Complementarity-Based Complementarity: The Choice of Mutually Unbiased Observables Shapes Quantum Uncertainty Relations.” Physical Review Research, vol. 7, no. 3, 033152, American Physical Society (APS), 2025, doi:10.1103/v24q-sl6n.' short: L.M. Serino, G. Chesi, B. Brecht, L. Maccone, C. Macchiavello, C. Silberhorn, Physical Review Research 7 (2025). date_created: 2025-12-18T16:04:45Z date_updated: 2025-12-18T16:05:45Z department: - _id: '15' - _id: '623' doi: 10.1103/v24q-sl6n intvolume: ' 7' issue: '3' language: - iso: eng publication: Physical Review Research publication_identifier: issn: - 2643-1564 publication_status: published publisher: American Physical Society (APS) status: public title: 'Complementarity-based complementarity: The choice of mutually unbiased observables shapes quantum uncertainty relations' type: journal_article user_id: '27150' volume: 7 year: '2025' ... --- _id: '63215' abstract: - lang: eng text: "Abstract\r\n High-dimensional time-frequency encodings have the potential to significantly advance quantum information science; however, practical applications require precise knowledge of the encoded quantum states, which becomes increasingly challenging for larger Hilbert spaces. Self-guided tomography (SGT) has emerged as a practical and scalable technique for this purpose in the spatial domain. Here, we apply SGT to estimate time-frequency states using a multi-output quantum pulse gate. We achieve fidelities of more than 99% for 3- and 5-dimensional states without the need for calibration or post-processing. We demonstrate the robustness of SGT against statistical and environmental noise, highlighting its efficacy in the photon-starved regime typical of quantum information applications." article_number: '025024' author: - first_name: Laura Maria full_name: Serino, Laura Maria id: '88242' last_name: Serino - first_name: Markus full_name: Rambach, Markus last_name: Rambach - first_name: Benjamin full_name: Brecht, Benjamin id: '27150' last_name: Brecht orcid: '0000-0003-4140-0556 ' - first_name: Jacquiline full_name: Romero, Jacquiline last_name: Romero - first_name: Christine full_name: Silberhorn, Christine id: '26263' last_name: Silberhorn citation: ama: Serino LM, Rambach M, Brecht B, Romero J, Silberhorn C. Self-guided tomography of time-frequency qudits. Quantum Science and Technology. 2025;10(2). doi:10.1088/2058-9565/adb0ea apa: Serino, L. M., Rambach, M., Brecht, B., Romero, J., & Silberhorn, C. (2025). Self-guided tomography of time-frequency qudits. Quantum Science and Technology, 10(2), Article 025024. https://doi.org/10.1088/2058-9565/adb0ea bibtex: '@article{Serino_Rambach_Brecht_Romero_Silberhorn_2025, title={Self-guided tomography of time-frequency qudits}, volume={10}, DOI={10.1088/2058-9565/adb0ea}, number={2025024}, journal={Quantum Science and Technology}, publisher={IOP Publishing}, author={Serino, Laura Maria and Rambach, Markus and Brecht, Benjamin and Romero, Jacquiline and Silberhorn, Christine}, year={2025} }' chicago: Serino, Laura Maria, Markus Rambach, Benjamin Brecht, Jacquiline Romero, and Christine Silberhorn. “Self-Guided Tomography of Time-Frequency Qudits.” Quantum Science and Technology 10, no. 2 (2025). https://doi.org/10.1088/2058-9565/adb0ea. ieee: 'L. M. Serino, M. Rambach, B. Brecht, J. Romero, and C. Silberhorn, “Self-guided tomography of time-frequency qudits,” Quantum Science and Technology, vol. 10, no. 2, Art. no. 025024, 2025, doi: 10.1088/2058-9565/adb0ea.' mla: Serino, Laura Maria, et al. “Self-Guided Tomography of Time-Frequency Qudits.” Quantum Science and Technology, vol. 10, no. 2, 025024, IOP Publishing, 2025, doi:10.1088/2058-9565/adb0ea. short: L.M. Serino, M. Rambach, B. Brecht, J. Romero, C. Silberhorn, Quantum Science and Technology 10 (2025). date_created: 2025-12-18T16:07:11Z date_updated: 2025-12-18T16:07:35Z department: - _id: '15' - _id: '623' doi: 10.1088/2058-9565/adb0ea intvolume: ' 10' issue: '2' language: - iso: eng publication: Quantum Science and Technology publication_identifier: issn: - 2058-9565 publication_status: published publisher: IOP Publishing status: public title: Self-guided tomography of time-frequency qudits type: journal_article user_id: '27150' volume: 10 year: '2025' ...