[{"citation":{"ama":"Pionteck MN, Roeper M, Koppitz B, et al. Second-order nonlinear piezo-optic properties of single crystal lithium niobate thin films. Physical Review B. 2025;111(6). doi:10.1103/physrevb.111.064109","apa":"Pionteck, M. N., Roeper, M., Koppitz, B., Seddon, S. D., Rüsing, M., Padberg, L., Eigner, C., Silberhorn, C., Sanna, S., & Eng, L. M. (2025). Second-order nonlinear piezo-optic properties of single crystal lithium niobate thin films. Physical Review B, 111(6), Article 064109. https://doi.org/10.1103/physrevb.111.064109","chicago":"Pionteck, Mike N., Matthias Roeper, Boris Koppitz, Samuel D. Seddon, Michael Rüsing, Laura Padberg, Christof Eigner, Christine Silberhorn, Simone Sanna, and Lukas M. Eng. “Second-Order Nonlinear Piezo-Optic Properties of Single Crystal Lithium Niobate Thin Films.” Physical Review B 111, no. 6 (2025). https://doi.org/10.1103/physrevb.111.064109.","ieee":"M. N. Pionteck et al., “Second-order nonlinear piezo-optic properties of single crystal lithium niobate thin films,” Physical Review B, vol. 111, no. 6, Art. no. 064109, 2025, doi: 10.1103/physrevb.111.064109.","mla":"Pionteck, Mike N., et al. “Second-Order Nonlinear Piezo-Optic Properties of Single Crystal Lithium Niobate Thin Films.” Physical Review B, vol. 111, no. 6, 064109, American Physical Society (APS), 2025, doi:10.1103/physrevb.111.064109.","bibtex":"@article{Pionteck_Roeper_Koppitz_Seddon_Rüsing_Padberg_Eigner_Silberhorn_Sanna_Eng_2025, title={Second-order nonlinear piezo-optic properties of single crystal lithium niobate thin films}, volume={111}, DOI={10.1103/physrevb.111.064109}, number={6064109}, journal={Physical Review B}, publisher={American Physical Society (APS)}, author={Pionteck, Mike N. and Roeper, Matthias and Koppitz, Boris and Seddon, Samuel D. and Rüsing, Michael and Padberg, Laura and Eigner, Christof and Silberhorn, Christine and Sanna, Simone and Eng, Lukas M.}, year={2025} }","short":"M.N. Pionteck, M. Roeper, B. Koppitz, S.D. Seddon, M. Rüsing, L. Padberg, C. Eigner, C. Silberhorn, S. Sanna, L.M. Eng, Physical Review B 111 (2025)."},"publication_status":"published","user_id":"22501","department":[{"_id":"15"},{"_id":"623"},{"_id":"288"}],"title":"Second-order nonlinear piezo-optic properties of single crystal lithium niobate thin films","author":[{"first_name":"Mike N.","full_name":"Pionteck, Mike N.","last_name":"Pionteck"},{"last_name":"Roeper","full_name":"Roeper, Matthias","first_name":"Matthias"},{"last_name":"Koppitz","full_name":"Koppitz, Boris","first_name":"Boris"},{"last_name":"Seddon","full_name":"Seddon, Samuel D.","first_name":"Samuel D."},{"orcid":"0000-0003-4682-4577","last_name":"Rüsing","id":"22501","full_name":"Rüsing, Michael","first_name":"Michael"},{"last_name":"Padberg","id":"40300","first_name":"Laura","full_name":"Padberg, Laura"},{"orcid":"https://orcid.org/0000-0002-5693-3083","first_name":"Christof","full_name":"Eigner, Christof","id":"13244","last_name":"Eigner"},{"full_name":"Silberhorn, Christine","first_name":"Christine","last_name":"Silberhorn","id":"26263"},{"last_name":"Sanna","first_name":"Simone","full_name":"Sanna, Simone"},{"first_name":"Lukas M.","full_name":"Eng, Lukas M.","last_name":"Eng"}],"abstract":[{"text":"Stress plays a crucial role in thin films and layered systems, and thus significantly influences the material's electrical, mechanical and (nonlinear) optical responses. Despite lithium niobate's wide applicability as a nonlinear optical material, the impact of mechanical stress on its nonlinear optical properties is not well characterized. In this work, we systematically study both experimentally and theoretically, the nonlinear optical responses of thin film lithium niobate (TFLN) single crystals. Compressive and tensile stress is applied in our experiment using a piezodriven strain cell. We then record the second-harmonic-generated (SHG) response in back-reflection geometry, and compare these results to theoretical modeling using density functional theory (DFT). Both methods consistently reveal that uniaxial stress induces changes of the nonlinear optical susceptibility of certain tensor elements on the order of up to 1 pm/(V GPa). The exact value depends on the tensor element that is addressed in our SHG analysis, on the crystal orientation, and also whether using compressive or tensile stresses. Furthermore, a lowering of the crystal symmetry when applying stress along the x or y crystallographic axes is observed by the appearance of new nonlinear optical tensor elements within the strained crystals.","lang":"eng"}],"doi":"10.1103/physrevb.111.064109","intvolume":" 111","_id":"59276","volume":111,"article_number":"064109","issue":"6","date_updated":"2025-04-02T16:24:47Z","date_created":"2025-04-02T16:21:47Z","publication":"Physical Review B","quality_controlled":"1","publisher":"American Physical Society (APS)","language":[{"iso":"eng"}],"type":"journal_article","year":"2025","publication_identifier":{"issn":["2469-9950","2469-9969"]},"status":"public"},{"page":"537-548","volume":10,"type":"journal_article","publication":"Nanoscale Horizons","quality_controlled":"1","user_id":"16199","project":[{"name":"TRR 142: TRR 142 - Maßgeschneiderte nichtlineare Photonik: Von grundlegenden Konzepten zu funktionellen Strukturen","_id":"53","grant_number":"231447078"},{"grant_number":"231447078","_id":"168","name":"TRR 142 - B07: TRR 142 - Polaronen-Einfluss auf die optischen Eigenschaften von Lithiumniobat (B07*)"},{"name":"TRR 142 - B: TRR 142 - Project Area B","_id":"55"},{"name":"Hochleistungsrechner Noctua in Paderborn","_id":"445","grant_number":"367360193"},{"_id":"52","name":"PC2: Computing Resources Provided by the Paderborn Center for Parallel Computing"}],"doi":"10.1039/d4nh00546e","abstract":[{"lang":"eng","text":"We present a cost-effective self-assembly method to fabricate low-density dimer NPs in an NPoM architecture, using the M13 phage as a spacer layer. This will enable the development of dynamic plasmonic devices and advanced sensing applications."}],"title":"Self-assembly of isolated plasmonic dimers with sub-5 nm gaps on a metallic mirror","date_updated":"2025-07-09T14:04:39Z","_id":"58642","language":[{"iso":"eng"}],"year":"2025","publication_identifier":{"issn":["2055-6756","2055-6764"]},"status":"public","date_created":"2025-02-14T08:13:10Z","publisher":"Royal Society of Chemistry (RSC)","department":[{"_id":"15"},{"_id":"230"},{"_id":"289"},{"_id":"623"},{"_id":"35"},{"_id":"295"},{"_id":"170"},{"_id":"429"},{"_id":"27"}],"citation":{"short":"V. Devaraj, I.A. Ruiz Alvarado, J.-M. Lee, J.-W. Oh, U. Gerstmann, W.G. Schmidt, T. Zentgraf, Nanoscale Horizons 10 (2025) 537–548.","bibtex":"@article{Devaraj_Ruiz Alvarado_Lee_Oh_Gerstmann_Schmidt_Zentgraf_2025, title={Self-assembly of isolated plasmonic dimers with sub-5 nm gaps on a metallic mirror}, volume={10}, DOI={10.1039/d4nh00546e}, journal={Nanoscale Horizons}, publisher={Royal Society of Chemistry (RSC)}, author={Devaraj, Vasanthan and Ruiz Alvarado, Isaac Azahel and Lee, Jong-Min and Oh, Jin-Woo and Gerstmann, Uwe and Schmidt, Wolf Gero and Zentgraf, Thomas}, year={2025}, pages={537–548} }","mla":"Devaraj, Vasanthan, et al. “Self-Assembly of Isolated Plasmonic Dimers with Sub-5 Nm Gaps on a Metallic Mirror.” Nanoscale Horizons, vol. 10, Royal Society of Chemistry (RSC), 2025, pp. 537–48, doi:10.1039/d4nh00546e.","ieee":"V. Devaraj et al., “Self-assembly of isolated plasmonic dimers with sub-5 nm gaps on a metallic mirror,” Nanoscale Horizons, vol. 10, pp. 537–548, 2025, doi: 10.1039/d4nh00546e.","chicago":"Devaraj, Vasanthan, Isaac Azahel Ruiz Alvarado, Jong-Min Lee, Jin-Woo Oh, Uwe Gerstmann, Wolf Gero Schmidt, and Thomas Zentgraf. “Self-Assembly of Isolated Plasmonic Dimers with Sub-5 Nm Gaps on a Metallic Mirror.” Nanoscale Horizons 10 (2025): 537–48. https://doi.org/10.1039/d4nh00546e.","ama":"Devaraj V, Ruiz Alvarado IA, Lee J-M, et al. Self-assembly of isolated plasmonic dimers with sub-5 nm gaps on a metallic mirror. Nanoscale Horizons. 2025;10:537-548. doi:10.1039/d4nh00546e","apa":"Devaraj, V., Ruiz Alvarado, I. A., Lee, J.-M., Oh, J.-W., Gerstmann, U., Schmidt, W. G., & Zentgraf, T. (2025). Self-assembly of isolated plasmonic dimers with sub-5 nm gaps on a metallic mirror. Nanoscale Horizons, 10, 537–548. https://doi.org/10.1039/d4nh00546e"},"publication_status":"published","intvolume":" 10","article_type":"original","author":[{"id":"103814","last_name":"Devaraj","full_name":"Devaraj, Vasanthan","first_name":"Vasanthan"},{"orcid":"0000-0002-4710-1170","id":"79462","last_name":"Ruiz Alvarado","first_name":"Isaac Azahel","full_name":"Ruiz Alvarado, Isaac Azahel"},{"full_name":"Lee, Jong-Min","first_name":"Jong-Min","last_name":"Lee"},{"first_name":"Jin-Woo","full_name":"Oh, Jin-Woo","last_name":"Oh"},{"orcid":"0000-0002-4476-223X","id":"171","last_name":"Gerstmann","full_name":"Gerstmann, Uwe","first_name":"Uwe"},{"orcid":"0000-0002-2717-5076","id":"468","last_name":"Schmidt","first_name":"Wolf Gero","full_name":"Schmidt, Wolf Gero"},{"orcid":"0000-0002-8662-1101","id":"30525","last_name":"Zentgraf","full_name":"Zentgraf, Thomas","first_name":"Thomas"}]},{"publication_status":"published","user_id":"55629","citation":{"ieee":"T. Schapeler, F. Schlue, M. Stefszky, B. Brecht, C. Silberhorn, and T. Bartley, “Optimizing photon-number resolution with superconducting nanowire multi-photon detectors,” in Advanced Photon Counting Techniques XIX, 2025, doi: 10.1117/12.3054905.","short":"T. Schapeler, F. Schlue, M. Stefszky, B. Brecht, C. Silberhorn, T. Bartley, in: M.A. Itzler, K.A. McIntosh, J.C. Bienfang (Eds.), Advanced Photon Counting Techniques XIX, SPIE, 2025.","chicago":"Schapeler, Timon, Fabian Schlue, Michael Stefszky, Benjamin Brecht, Christine Silberhorn, and Tim Bartley. “Optimizing Photon-Number Resolution with Superconducting Nanowire Multi-Photon Detectors.” In Advanced Photon Counting Techniques XIX, edited by Mark A. Itzler, K. Alex McIntosh, and Joshua C. Bienfang. SPIE, 2025. https://doi.org/10.1117/12.3054905.","ama":"Schapeler T, Schlue F, Stefszky M, Brecht B, Silberhorn C, Bartley T. Optimizing photon-number resolution with superconducting nanowire multi-photon detectors. In: Itzler MA, McIntosh KA, Bienfang JC, eds. Advanced Photon Counting Techniques XIX. SPIE; 2025. doi:10.1117/12.3054905","bibtex":"@inproceedings{Schapeler_Schlue_Stefszky_Brecht_Silberhorn_Bartley_2025, title={Optimizing photon-number resolution with superconducting nanowire multi-photon detectors}, DOI={10.1117/12.3054905}, booktitle={Advanced Photon Counting Techniques XIX}, publisher={SPIE}, author={Schapeler, Timon and Schlue, Fabian and Stefszky, Michael and Brecht, Benjamin and Silberhorn, Christine and Bartley, Tim}, editor={Itzler, Mark A. and McIntosh, K. Alex and Bienfang, Joshua C.}, year={2025} }","apa":"Schapeler, T., Schlue, F., Stefszky, M., Brecht, B., Silberhorn, C., & Bartley, T. (2025). Optimizing photon-number resolution with superconducting nanowire multi-photon detectors. In M. A. Itzler, K. A. McIntosh, & J. C. Bienfang (Eds.), Advanced Photon Counting Techniques XIX. SPIE. https://doi.org/10.1117/12.3054905","mla":"Schapeler, Timon, et al. “Optimizing Photon-Number Resolution with Superconducting Nanowire Multi-Photon Detectors.” Advanced Photon Counting Techniques XIX, edited by Mark A. Itzler et al., SPIE, 2025, doi:10.1117/12.3054905."},"department":[{"_id":"15"},{"_id":"623"}],"author":[{"id":"55629","last_name":"Schapeler","full_name":"Schapeler, Timon","first_name":"Timon","orcid":"0000-0001-7652-1716"},{"id":"63579","last_name":"Schlue","first_name":"Fabian","full_name":"Schlue, Fabian"},{"first_name":"Michael","full_name":"Stefszky, Michael","last_name":"Stefszky","id":"42777"},{"last_name":"Brecht","id":"27150","full_name":"Brecht, Benjamin","first_name":"Benjamin","orcid":"0000-0003-4140-0556 "},{"last_name":"Silberhorn","id":"26263","full_name":"Silberhorn, Christine","first_name":"Christine"},{"full_name":"Bartley, Tim","first_name":"Tim","id":"49683","last_name":"Bartley"}],"editor":[{"full_name":"Itzler, Mark A.","first_name":"Mark A.","last_name":"Itzler"},{"last_name":"McIntosh","full_name":"McIntosh, K. Alex","first_name":"K. Alex"},{"last_name":"Bienfang","first_name":"Joshua C.","full_name":"Bienfang, Joshua C."}],"title":"Optimizing photon-number resolution with superconducting nanowire multi-photon detectors","doi":"10.1117/12.3054905","project":[{"grant_number":"101042399","call_identifier":"ERC","_id":"239","name":"QuESADILLA: ERC-Grant: QuESADILLA: Quantum Engineering Superconducting Array Detectors in Low-Light Applications"},{"name":"PhoQuant--QCTest: PhoQuant: Photonische Quantencomputer - Quantencomputing Testplattform","_id":"191","grant_number":"13N16103"}],"_id":"60587","date_updated":"2025-07-11T09:22:11Z","publisher":"SPIE","date_created":"2025-07-11T09:18:09Z","publication":"Advanced Photon Counting Techniques XIX","status":"public","language":[{"iso":"eng"}],"type":"conference","year":"2025"},{"article_type":"original","author":[{"last_name":"Sidorova","full_name":"Sidorova, Mariia","first_name":"Mariia"},{"full_name":"Schapeler, Timon","first_name":"Timon","id":"55629","last_name":"Schapeler","orcid":"0000-0001-7652-1716"},{"last_name":"Semenov","first_name":"Alexej D.","full_name":"Semenov, Alexej D."},{"id":"63579","last_name":"Schlue","full_name":"Schlue, Fabian","first_name":"Fabian"},{"last_name":"Stefszky","id":"42777","first_name":"Michael","full_name":"Stefszky, Michael"},{"first_name":"Benjamin","full_name":"Brecht, Benjamin","last_name":"Brecht","id":"27150","orcid":"0000-0003-4140-0556 "},{"full_name":"Silberhorn, Christine","first_name":"Christine","id":"26263","last_name":"Silberhorn"},{"last_name":"Bartley","id":"49683","full_name":"Bartley, Tim","first_name":"Tim"}],"intvolume":" 10","citation":{"short":"M. Sidorova, T. Schapeler, A.D. Semenov, F. Schlue, M. Stefszky, B. Brecht, C. Silberhorn, T. Bartley, APL Photonics 10 (2025).","bibtex":"@article{Sidorova_Schapeler_Semenov_Schlue_Stefszky_Brecht_Silberhorn_Bartley_2025, title={Jitter in photon-number-resolved detection by superconducting nanowires}, volume={10}, DOI={10.1063/5.0273752}, number={8086113}, journal={APL Photonics}, publisher={AIP Publishing}, author={Sidorova, Mariia and Schapeler, Timon and Semenov, Alexej D. and Schlue, Fabian and Stefszky, Michael and Brecht, Benjamin and Silberhorn, Christine and Bartley, Tim}, year={2025} }","mla":"Sidorova, Mariia, et al. “Jitter in Photon-Number-Resolved Detection by Superconducting Nanowires.” APL Photonics, vol. 10, no. 8, 086113, AIP Publishing, 2025, doi:10.1063/5.0273752.","ieee":"M. Sidorova et al., “Jitter in photon-number-resolved detection by superconducting nanowires,” APL Photonics, vol. 10, no. 8, Art. no. 086113, 2025, doi: 10.1063/5.0273752.","chicago":"Sidorova, Mariia, Timon Schapeler, Alexej D. Semenov, Fabian Schlue, Michael Stefszky, Benjamin Brecht, Christine Silberhorn, and Tim Bartley. “Jitter in Photon-Number-Resolved Detection by Superconducting Nanowires.” APL Photonics 10, no. 8 (2025). https://doi.org/10.1063/5.0273752.","apa":"Sidorova, M., Schapeler, T., Semenov, A. D., Schlue, F., Stefszky, M., Brecht, B., Silberhorn, C., & Bartley, T. (2025). Jitter in photon-number-resolved detection by superconducting nanowires. APL Photonics, 10(8), Article 086113. https://doi.org/10.1063/5.0273752","ama":"Sidorova M, Schapeler T, Semenov AD, et al. Jitter in photon-number-resolved detection by superconducting nanowires. APL Photonics. 2025;10(8). doi:10.1063/5.0273752"},"publication_status":"published","department":[{"_id":"623"},{"_id":"15"}],"date_created":"2025-09-01T11:12:19Z","publisher":"AIP Publishing","language":[{"iso":"eng"}],"year":"2025","publication_identifier":{"issn":["2378-0967"]},"status":"public","_id":"61110","date_updated":"2025-09-02T10:47:08Z","title":"Jitter in photon-number-resolved detection by superconducting nanowires","project":[{"name":"PhoQuant: Photonische Quantencomputer - Quantencomputing Testplattform","_id":"191"},{"_id":"239","name":"ERC-Grant: QuESADILLA: Quantum Engineering Superconducting Array Detectors in Low-Light Applications"}],"doi":"10.1063/5.0273752","abstract":[{"lang":"eng","text":"By analyzing the physics of multi-photon absorption in superconducting nanowire single-photon detectors (SNSPDs), we identify physical components of jitter. From this, we formulate a quantitative physical model of the multi-photon detector response that combines the local detection mechanism and local fluctuations (hotspot formation and intrinsic jitter) with the thermoelectric dynamics of resistive domains. Our model provides an excellent description of the arrival-time histogram of a commercial SNSPD across several orders of magnitude, both in arrival-time probability and across mean photon number. This is achieved with just three fitting parameters: the scaling of the mean arrival time of voltage response pulses, as well as the Gaussian and exponential jitter components. Our findings have important implications for photon-number-resolving detector design, as well as applications requiring low jitter, such as light detection and ranging (LIDAR)."}],"keyword":["Jitter","PNR","SNSPD"],"main_file_link":[{"open_access":"1"}],"user_id":"55629","oa":"1","external_id":{"arxiv":["arXiv:2503.17146"]},"publication":"APL Photonics","type":"journal_article","volume":10,"article_number":"086113","issue":"8"},{"publisher":"American Physical Society (APS)","date_created":"2025-09-12T10:37:34Z","publication":"Physical Review A","status":"public","language":[{"iso":"eng"}],"publication_identifier":{"issn":["2469-9926","2469-9934"]},"year":"2025","type":"journal_article","volume":111,"_id":"61245","issue":"3","date_updated":"2025-09-12T10:42:16Z","article_number":"032404","author":[{"last_name":"Barkhausen","id":"63631","full_name":"Barkhausen, Franziska","first_name":"Franziska"},{"last_name":"Ares Santos","full_name":"Ares Santos, Laura","first_name":"Laura"},{"first_name":"Stefan","full_name":"Schumacher, Stefan","id":"27271","last_name":"Schumacher","orcid":"0000-0003-4042-4951"},{"orcid":"0000-0002-5844-3205","full_name":"Sperling, Jan","first_name":"Jan","last_name":"Sperling","id":"75127"}],"title":"Entanglement between dependent degrees of freedom: Quasiparticle correlations","intvolume":" 111","doi":"10.1103/physreva.111.032404","project":[{"_id":"53","name":"TRR 142: Maßgeschneiderte nichtlineare Photonik: Von grundlegenden Konzepten zu funktionellen Strukturen"},{"_id":"54","name":"TRR 142 - Project Area A"},{"name":"TRR 142 - Project Area C","_id":"56"},{"_id":"61","name":"TRR 142; TP A04: Nichtlineare Quantenprozesstomographie und Photonik mit Polaritonen in Mikrokavitäten"},{"_id":"174","name":"TRR 142 ; TP: C10: Erzeugung und Charakterisierung von Quantenlicht in nichtlinearen Systemen: Eine theoretische Analyse"},{"name":"PhoQC: Photonisches Quantencomputing","_id":"266"}],"publication_status":"published","user_id":"16199","citation":{"ieee":"F. Barkhausen, L. Ares Santos, S. Schumacher, and J. Sperling, “Entanglement between dependent degrees of freedom: Quasiparticle correlations,” Physical Review A, vol. 111, no. 3, Art. no. 032404, 2025, doi: 10.1103/physreva.111.032404.","chicago":"Barkhausen, Franziska, Laura Ares Santos, Stefan Schumacher, and Jan Sperling. “Entanglement between Dependent Degrees of Freedom: Quasiparticle Correlations.” Physical Review A 111, no. 3 (2025). https://doi.org/10.1103/physreva.111.032404.","ama":"Barkhausen F, Ares Santos L, Schumacher S, Sperling J. Entanglement between dependent degrees of freedom: Quasiparticle correlations. Physical Review A. 2025;111(3). doi:10.1103/physreva.111.032404","apa":"Barkhausen, F., Ares Santos, L., Schumacher, S., & Sperling, J. (2025). Entanglement between dependent degrees of freedom: Quasiparticle correlations. Physical Review A, 111(3), Article 032404. https://doi.org/10.1103/physreva.111.032404","short":"F. Barkhausen, L. Ares Santos, S. Schumacher, J. Sperling, Physical Review A 111 (2025).","bibtex":"@article{Barkhausen_Ares Santos_Schumacher_Sperling_2025, title={Entanglement between dependent degrees of freedom: Quasiparticle correlations}, volume={111}, DOI={10.1103/physreva.111.032404}, number={3032404}, journal={Physical Review A}, publisher={American Physical Society (APS)}, author={Barkhausen, Franziska and Ares Santos, Laura and Schumacher, Stefan and Sperling, Jan}, year={2025} }","mla":"Barkhausen, Franziska, et al. “Entanglement between Dependent Degrees of Freedom: Quasiparticle Correlations.” Physical Review A, vol. 111, no. 3, 032404, American Physical Society (APS), 2025, doi:10.1103/physreva.111.032404."},"department":[{"_id":"15"},{"_id":"170"},{"_id":"297"},{"_id":"706"},{"_id":"35"},{"_id":"230"},{"_id":"623"},{"_id":"429"}]},{"main_file_link":[{"open_access":"1","url":"https://doi.org/10.1016/j.ssi.2025.116949"}],"oa":"1","user_id":"22501","doi":"10.1016/j.ssi.2025.116949","abstract":[{"lang":"eng","text":"Conductive ferroelectric domain walls (DWs) represent a promising topical system for the development of nanoelectronic components and device sensors to be operational at elevated temperatures. DWs show very different properties as compared to their hosting bulk crystal, in particular with respect to the high local electrical conductivity. The objective of this work is to demonstrate DW conductivity up to temperatures as high as 400 °C which extends previous studies significantly. Experimental investigation of the DW conductivity of charged, inclined DWs is performed using 5 mol % MgO-doped lithium niobate single crystals. Current–voltage ( ) curves are determined by DC electrometer measurements and impedance spectroscopy and found to be identical. Moreover, impedance spectroscopy enables to recognize artifacts such as damaged electrodes. Temperature dependent measurements over repeated heating cycles reveal two distinct thermal activation energies for a given DW, with the higher of the activation energies only measured at higher temperatures. Depending on the specific sample, the higher activation energy is found above 160 °C to 230 °C. This suggests, in turn, that more than one type of defect/polaron is involved, and that the dominant transport mechanism changes with increasing temperature. First principles atomistic modeling suggests that the conductivity of inclined domain walls cannot be solely explained by the formation of a 2D carrier gas and must be supported by hopping processes. This holds true even at temperatures as high as 400 °C. Our investigations underline the potential to extend DW current based nanoelectronic and sensor applications even into the so-far unexplored temperature range up to 400 °C."}],"title":"Demonstration of domain wall current in MgO-doped lithium niobate single crystals up to 400°C","article_number":"116949","volume":429,"type":"journal_article","publication":"Solid State Ionics","quality_controlled":"1","department":[{"_id":"15"},{"_id":"288"},{"_id":"623"}],"publication_status":"published","citation":{"ama":"Wulfmeier H, Yakhnevych U, Boekhoff C, et al. Demonstration of domain wall current in MgO-doped lithium niobate single crystals up to 400°C. Solid State Ionics. 2025;429. doi:10.1016/j.ssi.2025.116949","bibtex":"@article{Wulfmeier_Yakhnevych_Boekhoff_Diima_Kunzner_Verhoff_Paul_Ratzenberger_Beyreuther_Gössel_et al._2025, title={Demonstration of domain wall current in MgO-doped lithium niobate single crystals up to 400°C}, volume={429}, DOI={10.1016/j.ssi.2025.116949}, number={116949}, journal={Solid State Ionics}, publisher={Elsevier BV}, author={Wulfmeier, Hendrik and Yakhnevych, Uliana and Boekhoff, Cornelius and Diima, Allan and Kunzner, Marlo and Verhoff, Leonard M. and Paul, Jonas and Ratzenberger, Julius and Beyreuther, Elke and Gössel, Joshua and et al.}, year={2025} }","apa":"Wulfmeier, H., Yakhnevych, U., Boekhoff, C., Diima, A., Kunzner, M., Verhoff, L. M., Paul, J., Ratzenberger, J., Beyreuther, E., Gössel, J., Kiseleva, I., Rüsing, M., Sanna, S., Eng, L. M., & Fritze, H. (2025). Demonstration of domain wall current in MgO-doped lithium niobate single crystals up to 400°C. Solid State Ionics, 429, Article 116949. https://doi.org/10.1016/j.ssi.2025.116949","mla":"Wulfmeier, Hendrik, et al. “Demonstration of Domain Wall Current in MgO-Doped Lithium Niobate Single Crystals up to 400°C.” Solid State Ionics, vol. 429, 116949, Elsevier BV, 2025, doi:10.1016/j.ssi.2025.116949.","ieee":"H. Wulfmeier et al., “Demonstration of domain wall current in MgO-doped lithium niobate single crystals up to 400°C,” Solid State Ionics, vol. 429, Art. no. 116949, 2025, doi: 10.1016/j.ssi.2025.116949.","chicago":"Wulfmeier, Hendrik, Uliana Yakhnevych, Cornelius Boekhoff, Allan Diima, Marlo Kunzner, Leonard M. Verhoff, Jonas Paul, et al. “Demonstration of Domain Wall Current in MgO-Doped Lithium Niobate Single Crystals up to 400°C.” Solid State Ionics 429 (2025). https://doi.org/10.1016/j.ssi.2025.116949.","short":"H. Wulfmeier, U. Yakhnevych, C. Boekhoff, A. Diima, M. Kunzner, L.M. Verhoff, J. Paul, J. Ratzenberger, E. Beyreuther, J. Gössel, I. Kiseleva, M. Rüsing, S. Sanna, L.M. Eng, H. Fritze, Solid State Ionics 429 (2025)."},"intvolume":" 429","author":[{"first_name":"Hendrik","full_name":"Wulfmeier, Hendrik","last_name":"Wulfmeier"},{"first_name":"Uliana","full_name":"Yakhnevych, Uliana","last_name":"Yakhnevych"},{"first_name":"Cornelius","full_name":"Boekhoff, Cornelius","last_name":"Boekhoff"},{"full_name":"Diima, Allan","first_name":"Allan","last_name":"Diima"},{"first_name":"Marlo","full_name":"Kunzner, Marlo","last_name":"Kunzner"},{"full_name":"Verhoff, Leonard M.","first_name":"Leonard M.","last_name":"Verhoff"},{"last_name":"Paul","full_name":"Paul, Jonas","first_name":"Jonas"},{"full_name":"Ratzenberger, Julius","first_name":"Julius","last_name":"Ratzenberger"},{"full_name":"Beyreuther, Elke","first_name":"Elke","last_name":"Beyreuther"},{"last_name":"Gössel","first_name":"Joshua","full_name":"Gössel, Joshua"},{"last_name":"Kiseleva","first_name":"Iuliia","full_name":"Kiseleva, Iuliia"},{"id":"22501","last_name":"Rüsing","first_name":"Michael","full_name":"Rüsing, Michael","orcid":"0000-0003-4682-4577"},{"last_name":"Sanna","first_name":"Simone","full_name":"Sanna, Simone"},{"first_name":"Lukas M.","full_name":"Eng, Lukas M.","last_name":"Eng"},{"last_name":"Fritze","full_name":"Fritze, Holger","first_name":"Holger"}],"article_type":"original","date_updated":"2025-09-17T16:19:51Z","_id":"61338","status":"public","language":[{"iso":"eng"}],"publication_identifier":{"issn":["0167-2738"]},"year":"2025","publisher":"Elsevier BV","date_created":"2025-09-17T16:18:18Z"},{"date_updated":"2025-09-17T16:18:02Z","_id":"61337","language":[{"iso":"eng"}],"year":"2025","publication_identifier":{"issn":["0021-8979","1089-7550"]},"status":"public","date_created":"2025-09-17T16:16:04Z","publisher":"AIP Publishing","funded_apc":"1","department":[{"_id":"15"},{"_id":"623"}],"citation":{"short":"B. Koppitz, T. Saxena, F. Bernhardt, S. Ganschow, S. Sanna, M. Rüsing, L.M. Eng, Journal of Applied Physics 138 (2025).","mla":"Koppitz, Boris, et al. “Second Harmonic Generation Contrasts of Ferroelectric Domain Structures and Composition in Lithium Niobate–Tantalate Mixed Crystals.” Journal of Applied Physics, vol. 138, no. 3, 034101, AIP Publishing, 2025, doi:10.1063/5.0276183.","bibtex":"@article{Koppitz_Saxena_Bernhardt_Ganschow_Sanna_Rüsing_Eng_2025, title={Second harmonic generation contrasts of ferroelectric domain structures and composition in lithium niobate–tantalate mixed crystals}, volume={138}, DOI={10.1063/5.0276183}, number={3034101}, journal={Journal of Applied Physics}, publisher={AIP Publishing}, author={Koppitz, Boris and Saxena, Tanya and Bernhardt, Felix and Ganschow, Steffen and Sanna, Simone and Rüsing, Michael and Eng, Lukas M.}, year={2025} }","chicago":"Koppitz, Boris, Tanya Saxena, Felix Bernhardt, Steffen Ganschow, Simone Sanna, Michael Rüsing, and Lukas M. Eng. “Second Harmonic Generation Contrasts of Ferroelectric Domain Structures and Composition in Lithium Niobate–Tantalate Mixed Crystals.” Journal of Applied Physics 138, no. 3 (2025). https://doi.org/10.1063/5.0276183.","ieee":"B. Koppitz et al., “Second harmonic generation contrasts of ferroelectric domain structures and composition in lithium niobate–tantalate mixed crystals,” Journal of Applied Physics, vol. 138, no. 3, Art. no. 034101, 2025, doi: 10.1063/5.0276183.","ama":"Koppitz B, Saxena T, Bernhardt F, et al. Second harmonic generation contrasts of ferroelectric domain structures and composition in lithium niobate–tantalate mixed crystals. Journal of Applied Physics. 2025;138(3). doi:10.1063/5.0276183","apa":"Koppitz, B., Saxena, T., Bernhardt, F., Ganschow, S., Sanna, S., Rüsing, M., & Eng, L. M. (2025). Second harmonic generation contrasts of ferroelectric domain structures and composition in lithium niobate–tantalate mixed crystals. Journal of Applied Physics, 138(3), Article 034101. https://doi.org/10.1063/5.0276183"},"publication_status":"published","intvolume":" 138","author":[{"last_name":"Koppitz","first_name":"Boris","full_name":"Koppitz, Boris"},{"first_name":"Tanya","full_name":"Saxena, Tanya","last_name":"Saxena"},{"first_name":"Felix","full_name":"Bernhardt, Felix","last_name":"Bernhardt"},{"first_name":"Steffen","full_name":"Ganschow, Steffen","last_name":"Ganschow"},{"last_name":"Sanna","full_name":"Sanna, Simone","first_name":"Simone"},{"orcid":"0000-0003-4682-4577","last_name":"Rüsing","id":"22501","first_name":"Michael","full_name":"Rüsing, Michael"},{"first_name":"Lukas M.","full_name":"Eng, Lukas M.","last_name":"Eng"}],"article_number":"034101","issue":"3","volume":138,"type":"journal_article","quality_controlled":"1","publication":"Journal of Applied Physics","main_file_link":[{"open_access":"1","url":"https://pubs.aip.org/aip/jap/article/138/3/034101/3352909"}],"oa":"1","user_id":"22501","doi":"10.1063/5.0276183","abstract":[{"text":"Lithium niobate–tantalate mixed (LNT) crystals promise improved performance and new applications for optical, piezomechanical, or electrical devices when compared to the end composition compounds lithium niobate and lithium tantalate. The macroscopic properties of ferroelectrics highly depend on the structure of the underlying ferroelectric domains, which within mixed crystals can interact with the local changes in chemical compositions. In this work, we demonstrate how ferroelectric domain walls can unambiguously be identified and distinguished from local changes in composition by correlating piezoresponse force microscopy with second harmonic generation microscopy, using the Cherenkov contrast, reference crystal contrast, and negative phase mismatching contrast. We demonstrate how measuring the associated intensity change when approaching negative phase mismatching can be used to deduce the local tantalum concentration fast and over a large sample area. Based on these results, we study the natural domain structures that appear from Czochralski-grown, multi-domain LNT solid solution crystals. The developed results and methods serve as the central foundation to poling these mixed crystal systems and are key for their integration and applications.","lang":"eng"}],"title":"Second harmonic generation contrasts of ferroelectric domain structures and composition in lithium niobate–tantalate mixed crystals"},{"type":"journal_article","publication":"Quantum","article_number":"1621","volume":9,"doi":"10.22331/q-2025-02-04-1621","abstract":[{"lang":"eng","text":"A unified theoretical approach to describe the properties of multimode squeezed light generated in a lossy medium is presented. This approach is valid for Markovian environments and includes both a model of discrete losses based on the beamsplitter approach and a generalized continuous loss model based on the spatial Langevin equation. For an important class of Gaussian states, we derive master equations for the second-order correlation functions and illustrate their solution for both frequency-independent and frequency-dependent losses. Studying the mode structure, we demonstrate that in a lossy environment no broadband basis without quadrature correlations between the different broadband modes exists. Therefore, various techniques and strategies to introduce broadband modes can be considered. We show that the Mercer expansion and the Williamson-Euler decomposition do not provide modes in which the maximal squeezing contained in the system can be measured. In turn, we find a new broadband basis that maximizes squeezing in the lossy system and present an algorithm to construct it."}],"project":[{"_id":"266","name":"PhoQC: PhoQC: Photonisches Quantencomputing"},{"_id":"52","name":"Computing Resources Provided by the Paderborn Center for Parallel Computing"}],"title":"Theory of Multimode Squeezed Light Generation in Lossy Media","user_id":"16199","status":"public","year":"2025","publication_identifier":{"issn":["2521-327X"]},"language":[{"iso":"eng"}],"publisher":"Verein zur Forderung des Open Access Publizierens in den Quantenwissenschaften","date_created":"2025-02-05T12:57:37Z","date_updated":"2025-09-18T13:22:26Z","_id":"58519","intvolume":" 9","author":[{"last_name":"Kopylov","first_name":"Denis A.","full_name":"Kopylov, Denis A."},{"id":"344","last_name":"Meier","first_name":"Torsten","full_name":"Meier, Torsten","orcid":"0000-0001-8864-2072"},{"last_name":"Sharapova","id":"60286","first_name":"Polina R.","full_name":"Sharapova, Polina R."}],"department":[{"_id":"15"},{"_id":"569"},{"_id":"170"},{"_id":"293"},{"_id":"35"},{"_id":"230"},{"_id":"623"},{"_id":"27"}],"publication_status":"published","citation":{"bibtex":"@article{Kopylov_Meier_Sharapova_2025, title={Theory of Multimode Squeezed Light Generation in Lossy Media}, volume={9}, DOI={10.22331/q-2025-02-04-1621}, number={1621}, journal={Quantum}, publisher={Verein zur Forderung des Open Access Publizierens in den Quantenwissenschaften}, author={Kopylov, Denis A. and Meier, Torsten and Sharapova, Polina R.}, year={2025} }","mla":"Kopylov, Denis A., et al. “Theory of Multimode Squeezed Light Generation in Lossy Media.” Quantum, vol. 9, 1621, Verein zur Forderung des Open Access Publizierens in den Quantenwissenschaften, 2025, doi:10.22331/q-2025-02-04-1621.","short":"D.A. Kopylov, T. Meier, P.R. Sharapova, Quantum 9 (2025).","apa":"Kopylov, D. A., Meier, T., & Sharapova, P. R. (2025). Theory of Multimode Squeezed Light Generation in Lossy Media. Quantum, 9, Article 1621. https://doi.org/10.22331/q-2025-02-04-1621","ama":"Kopylov DA, Meier T, Sharapova PR. Theory of Multimode Squeezed Light Generation in Lossy Media. Quantum. 2025;9. doi:10.22331/q-2025-02-04-1621","ieee":"D. A. Kopylov, T. Meier, and P. R. Sharapova, “Theory of Multimode Squeezed Light Generation in Lossy Media,” Quantum, vol. 9, Art. no. 1621, 2025, doi: 10.22331/q-2025-02-04-1621.","chicago":"Kopylov, Denis A., Torsten Meier, and Polina R. Sharapova. “Theory of Multimode Squeezed Light Generation in Lossy Media.” Quantum 9 (2025). https://doi.org/10.22331/q-2025-02-04-1621."}},{"file_date_updated":"2025-10-05T11:48:25Z","_id":"60891","date_updated":"2025-10-05T11:52:55Z","publisher":"Optica Publishing Group","date_created":"2025-08-06T09:36:30Z","status":"public","year":"2025","publication_identifier":{"issn":["2770-0208"]},"language":[{"iso":"eng"}],"publication_status":"published","citation":{"chicago":"Hammer, Manfred, Shahriar Khan, Behnood Taheri, Henna Farheen, and Jens Förstner. “TFLN Channel Waveguides of Rib and Strip Type: Properties of Guided Modes.” Optics Continuum 4, no. 10 (2025): 2356. https://doi.org/10.1364/optcon.569959.","ieee":"M. Hammer, S. Khan, B. Taheri, H. Farheen, and J. Förstner, “TFLN channel waveguides of rib and strip type: Properties of guided modes,” Optics Continuum, vol. 4, no. 10, p. 2356, 2025, doi: 10.1364/optcon.569959.","apa":"Hammer, M., Khan, S., Taheri, B., Farheen, H., & Förstner, J. (2025). TFLN channel waveguides of rib and strip type: Properties of guided modes. Optics Continuum, 4(10), 2356. https://doi.org/10.1364/optcon.569959","ama":"Hammer M, Khan S, Taheri B, Farheen H, Förstner J. TFLN channel waveguides of rib and strip type: Properties of guided modes. Optics Continuum. 2025;4(10):2356. doi:10.1364/optcon.569959","short":"M. Hammer, S. Khan, B. Taheri, H. Farheen, J. Förstner, Optics Continuum 4 (2025) 2356.","mla":"Hammer, Manfred, et al. “TFLN Channel Waveguides of Rib and Strip Type: Properties of Guided Modes.” Optics Continuum, vol. 4, no. 10, Optica Publishing Group, 2025, p. 2356, doi:10.1364/optcon.569959.","bibtex":"@article{Hammer_Khan_Taheri_Farheen_Förstner_2025, title={TFLN channel waveguides of rib and strip type: Properties of guided modes}, volume={4}, DOI={10.1364/optcon.569959}, number={10}, journal={Optics Continuum}, publisher={Optica Publishing Group}, author={Hammer, Manfred and Khan, Shahriar and Taheri, Behnood and Farheen, Henna and Förstner, Jens}, year={2025}, pages={2356} }"},"department":[{"_id":"61"},{"_id":"230"},{"_id":"429"},{"_id":"623"}],"author":[{"id":"48077","last_name":"Hammer","first_name":"Manfred","full_name":"Hammer, Manfred","orcid":"0000-0002-6331-9348"},{"first_name":"Shahriar","full_name":"Khan, Shahriar","last_name":"Khan"},{"first_name":"Behnood","full_name":"Taheri, Behnood","last_name":"Taheri"},{"orcid":"0000-0001-7730-3489","first_name":"Henna","full_name":"Farheen, Henna","id":"53444","last_name":"Farheen"},{"last_name":"Förstner","id":"158","first_name":"Jens","full_name":"Förstner, Jens","orcid":"0000-0001-7059-9862"}],"intvolume":" 4","volume":4,"page":"2356","issue":"10","ddc":["530"],"publication":"Optics Continuum","type":"journal_article","user_id":"158","keyword":["tet_topic_waveguide"],"file":[{"file_size":5417636,"file_name":"2025-08 Hammer - Optics Continuum - TFLN channel waveguides of rib and strip type. Properties of guided modes (official version).pdf","creator":"fossie","date_created":"2025-10-05T11:48:25Z","access_level":"closed","file_id":"61516","content_type":"application/pdf","relation":"main_file","date_updated":"2025-10-05T11:48:25Z","success":1}],"title":"TFLN channel waveguides of rib and strip type: Properties of guided modes","has_accepted_license":"1","abstract":[{"lang":"eng","text":"Straight dielectric waveguide channels made from slabs of thin-film lithium niobate (TFLN), or lithium niobate on insulator (LNOI), are investigated in the linear regime, for channels of rib and strip type with common trapezoidal cross sections, in Z-cut and X-cut samples at varying on-chip orientation. We clarify the theoretical basis for the waveguides with potentially non-diagonal core permittivity. Symmetry classes can be distinguished that differ in their consequences for potential modal degeneracy and polarization conversion. Our rigorous numerical analysis by means of a finite-element solver takes the anisotropy of the lithium niobate cores rigorously into account. We discuss extensive data for effective indices, polarization properties, and hybridization of guided modes, in single- and multimode channels. Scans over the waveguide width and orientation as primary parameters are complemented by a series of illustrations of vectorial mode profiles. These turn out to be essentially complex in cases of X-cut channels at non-crystal-axis-aligned orientations."}],"doi":"10.1364/optcon.569959"},{"_id":"61760","date_updated":"2025-10-08T15:22:30Z","date_created":"2025-10-08T15:20:13Z","publication":"Photonic Computing: From Materials and Devices to Systems and Applications II","publisher":"SPIE","language":[{"iso":"eng"}],"year":"2025","type":"conference","status":"public","citation":{"short":"H. Farheen, Y. Chen, P. Chen, A. Kryvobok, S. Peana, A. Senichev, V.M. Shalaev, A. Boltasseva, J. Förstner, A.V. Kildishev, in: X. Ni, W. Cai (Eds.), Photonic Computing: From Materials and Devices to Systems and Applications II, SPIE, 2025.","bibtex":"@inproceedings{Farheen_Chen_Chen_Kryvobok_Peana_Senichev_Shalaev_Boltasseva_Förstner_Kildishev_2025, title={Topology-optimized silicon nitride coupler for integrated single-photon emitters}, DOI={10.1117/12.3065734}, booktitle={Photonic Computing: From Materials and Devices to Systems and Applications II}, publisher={SPIE}, author={Farheen, Henna and Chen, Yuheng and Chen, Peigang and Kryvobok, Artem and Peana, Samuel and Senichev, Alexander and Shalaev, Vladimir M. and Boltasseva, Alexandra and Förstner, Jens and Kildishev, Alexander V.}, editor={Ni, Xingjie and Cai, Wenshan}, year={2025} }","mla":"Farheen, Henna, et al. “Topology-Optimized Silicon Nitride Coupler for Integrated Single-Photon Emitters.” Photonic Computing: From Materials and Devices to Systems and Applications II, edited by Xingjie Ni and Wenshan Cai, SPIE, 2025, doi:10.1117/12.3065734.","ieee":"H. Farheen et al., “Topology-optimized silicon nitride coupler for integrated single-photon emitters,” in Photonic Computing: From Materials and Devices to Systems and Applications II, 2025, doi: 10.1117/12.3065734.","chicago":"Farheen, Henna, Yuheng Chen, Peigang Chen, Artem Kryvobok, Samuel Peana, Alexander Senichev, Vladimir M. Shalaev, Alexandra Boltasseva, Jens Förstner, and Alexander V. Kildishev. “Topology-Optimized Silicon Nitride Coupler for Integrated Single-Photon Emitters.” In Photonic Computing: From Materials and Devices to Systems and Applications II, edited by Xingjie Ni and Wenshan Cai. SPIE, 2025. https://doi.org/10.1117/12.3065734.","apa":"Farheen, H., Chen, Y., Chen, P., Kryvobok, A., Peana, S., Senichev, A., Shalaev, V. M., Boltasseva, A., Förstner, J., & Kildishev, A. V. (2025). Topology-optimized silicon nitride coupler for integrated single-photon emitters. In X. Ni & W. Cai (Eds.), Photonic Computing: From Materials and Devices to Systems and Applications II. SPIE. https://doi.org/10.1117/12.3065734","ama":"Farheen H, Chen Y, Chen P, et al. Topology-optimized silicon nitride coupler for integrated single-photon emitters. In: Ni X, Cai W, eds. Photonic Computing: From Materials and Devices to Systems and Applications II. SPIE; 2025. doi:10.1117/12.3065734"},"keyword":["tet_topic_waveguide"],"publication_status":"published","user_id":"158","department":[{"_id":"61"},{"_id":"230"},{"_id":"429"},{"_id":"623"}],"title":"Topology-optimized silicon nitride coupler for integrated single-photon emitters","editor":[{"first_name":"Xingjie","full_name":"Ni, Xingjie","last_name":"Ni"},{"first_name":"Wenshan","full_name":"Cai, Wenshan","last_name":"Cai"}],"author":[{"orcid":"0000-0001-7730-3489","id":"53444","last_name":"Farheen","first_name":"Henna","full_name":"Farheen, Henna"},{"last_name":"Chen","full_name":"Chen, Yuheng","first_name":"Yuheng"},{"last_name":"Chen","full_name":"Chen, Peigang","first_name":"Peigang"},{"last_name":"Kryvobok","first_name":"Artem","full_name":"Kryvobok, Artem"},{"full_name":"Peana, Samuel","first_name":"Samuel","last_name":"Peana"},{"full_name":"Senichev, Alexander","first_name":"Alexander","last_name":"Senichev"},{"first_name":"Vladimir M.","full_name":"Shalaev, Vladimir M.","last_name":"Shalaev"},{"full_name":"Boltasseva, Alexandra","first_name":"Alexandra","last_name":"Boltasseva"},{"orcid":"0000-0001-7059-9862","last_name":"Förstner","id":"158","full_name":"Förstner, Jens","first_name":"Jens"},{"last_name":"Kildishev","first_name":"Alexander V.","full_name":"Kildishev, Alexander V."}],"doi":"10.1117/12.3065734","abstract":[{"text":"We present a topology-optimized silicon nitride (Si3N4) coupler designed to enhance the coupling efficiency between integrated single-photon emitters and photonic waveguide modes. By leveraging inverse design techniques, we optimize the coupler’s geometry to maximize power transfer while maintaining fabrication feasibility by improving mode overlap and directional emission, addressing the challenge of low coupling efficiency caused by size mismatch and material incompatibility. Simulations demonstrate a substantial enhancement in photon extraction and waveguide coupling. This approach can be extended to other photonic devices, offering a versatile framework for improving quantum light-matter interactions in integrated photonics.","lang":"eng"}]},{"date_updated":"2025-11-24T06:35:19Z","_id":"62286","status":"public","language":[{"iso":"eng"}],"publication_identifier":{"issn":["1094-4087"]},"year":"2025","publisher":"Optica Publishing Group","date_created":"2025-11-24T06:31:17Z","department":[{"_id":"15"},{"_id":"230"},{"_id":"289"},{"_id":"623"}],"publication_status":"published","citation":{"ama":"Li D, Liao Q, Xu B, et al. In vacuum metasurface for optical microtrap array. Optics Express. 2025;33(24). doi:10.1364/oe.580201","apa":"Li, D., Liao, Q., Xu, B., Zentgraf, T., Narvaez Castaneda, E., Zhou, Y., Qin, K., Xu, Z., Shen, H., & Huang, L. (2025). In vacuum metasurface for optical microtrap array. Optics Express, 33(24), Article 51085. https://doi.org/10.1364/oe.580201","ieee":"D. Li et al., “In vacuum metasurface for optical microtrap array,” Optics Express, vol. 33, no. 24, Art. no. 51085, 2025, doi: 10.1364/oe.580201.","chicago":"Li, Donghao, Qiming Liao, Beining Xu, Thomas Zentgraf, Emmanuel Narvaez Castaneda, Yaoting Zhou, Keyu Qin, Zhongxiao Xu, Heng Shen, and Lingling Huang. “In Vacuum Metasurface for Optical Microtrap Array.” Optics Express 33, no. 24 (2025). https://doi.org/10.1364/oe.580201.","bibtex":"@article{Li_Liao_Xu_Zentgraf_Narvaez Castaneda_Zhou_Qin_Xu_Shen_Huang_2025, title={In vacuum metasurface for optical microtrap array}, volume={33}, DOI={10.1364/oe.580201}, number={2451085}, journal={Optics Express}, publisher={Optica Publishing Group}, author={Li, Donghao and Liao, Qiming and Xu, Beining and Zentgraf, Thomas and Narvaez Castaneda, Emmanuel and Zhou, Yaoting and Qin, Keyu and Xu, Zhongxiao and Shen, Heng and Huang, Lingling}, year={2025} }","mla":"Li, Donghao, et al. “In Vacuum Metasurface for Optical Microtrap Array.” Optics Express, vol. 33, no. 24, 51085, Optica Publishing Group, 2025, doi:10.1364/oe.580201.","short":"D. Li, Q. Liao, B. Xu, T. Zentgraf, E. Narvaez Castaneda, Y. Zhou, K. Qin, Z. Xu, H. Shen, L. Huang, Optics Express 33 (2025)."},"intvolume":" 33","author":[{"full_name":"Li, Donghao","first_name":"Donghao","last_name":"Li"},{"first_name":"Qiming","full_name":"Liao, Qiming","last_name":"Liao"},{"last_name":"Xu","first_name":"Beining","full_name":"Xu, Beining"},{"id":"30525","last_name":"Zentgraf","full_name":"Zentgraf, Thomas","first_name":"Thomas","orcid":"0000-0002-8662-1101"},{"last_name":"Narvaez Castaneda","full_name":"Narvaez Castaneda, Emmanuel","first_name":"Emmanuel"},{"full_name":"Zhou, Yaoting","first_name":"Yaoting","last_name":"Zhou"},{"first_name":"Keyu","full_name":"Qin, Keyu","last_name":"Qin"},{"last_name":"Xu","full_name":"Xu, Zhongxiao","first_name":"Zhongxiao"},{"last_name":"Shen","first_name":"Heng","full_name":"Shen, Heng"},{"first_name":"Lingling","full_name":"Huang, Lingling","last_name":"Huang"}],"article_type":"original","issue":"24","article_number":"51085","volume":33,"type":"journal_article","quality_controlled":"1","publication":"Optics Express","main_file_link":[{"open_access":"1","url":"https://opg.optica.org/oe/fulltext.cfm?uri=oe-33-24-51085"}],"user_id":"30525","oa":"1","doi":"10.1364/oe.580201","abstract":[{"text":"Optical tweezer arrays of laser-cooled and individually controlled particles have revolutionized atomic, molecular, and optical physics. They afford exquisite capabilities for applications in quantum simulation of many-body physics, quantum computation, and sensing. Underlying this development is the technical maturity of generating scalable optical beams, enabled by active components and a high numerical aperture objective. However, such a complex combination of bulk optics outside the vacuum chamber is very sensitive to any vibration and drift. Here, we demonstrate the generation of a 3 × 3 static tweezer array with a single chip-scale multifunctional metasurface element in vacuum, replacing the meter-long free space optics. Fluorescence counts on the camera validate the successful trapping of the atomic ensemble array and showcase a promising strategy for integrated photonics with cold atom systems. The introduction of a polarization independent dual-wavelength metasurface significantly enhances fluorescence collection efficiency while reducing experimental complexity. This approach paves the way for scalable neutral atom platforms and offers a compelling route towards the realization of next generation quantum metasurfaces.","lang":"eng"}],"title":"In vacuum metasurface for optical microtrap array"},{"date_updated":"2025-11-27T07:07:16Z","_id":"62639","publication_date":"2025-01-23","status":"public","type":"patent","year":"2025","date_created":"2025-11-27T07:00:50Z","ipn":"DE102023212604B3","department":[{"_id":"58"},{"_id":"623"},{"_id":"288"}],"user_id":"38254","citation":{"ieee":"S. Kruse, C. Silberhorn, B. Brecht, and T. Schwabe, “Optisch basierter Digital-Analog-Umsetzer.” 2025.","short":"S. Kruse, C. Silberhorn, B. Brecht, T. Schwabe, (2025).","chicago":"Kruse, Stephan, Christine Silberhorn, Benjamin Brecht, and Tobias Schwabe. “Optisch Basierter Digital-Analog-Umsetzer,” 2025.","apa":"Kruse, S., Silberhorn, C., Brecht, B., & Schwabe, T. (2025). Optisch basierter Digital-Analog-Umsetzer.","ama":"Kruse S, Silberhorn C, Brecht B, Schwabe T. Optisch basierter Digital-Analog-Umsetzer. Published online 2025.","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} }","mla":"Kruse, Stephan, et al. Optisch Basierter Digital-Analog-Umsetzer. 2025."},"author":[{"full_name":"Kruse, Stephan","first_name":"Stephan","last_name":"Kruse","id":"38254"},{"full_name":"Silberhorn, Christine","first_name":"Christine","last_name":"Silberhorn","id":"26263"},{"orcid":"0000-0003-4140-0556 ","id":"27150","last_name":"Brecht","first_name":"Benjamin","full_name":"Brecht, Benjamin"},{"full_name":"Schwabe, Tobias","first_name":"Tobias","id":"39217","last_name":"Schwabe"}],"title":"Optisch basierter Digital-Analog-Umsetzer","ipc":"H03M 1/66"},{"date_created":"2025-12-02T19:21:33Z","publisher":"American Physical Society (APS)","language":[{"iso":"eng"}],"publication_identifier":{"issn":["2469-9950","2469-9969"]},"year":"2025","status":"public","_id":"62749","date_updated":"2025-12-02T19:23:55Z","article_type":"original","author":[{"last_name":"Hempel","first_name":"F.","full_name":"Hempel, F."},{"orcid":"0000-0003-4682-4577","first_name":"Michael","full_name":"Rüsing, Michael","id":"22501","last_name":"Rüsing"},{"first_name":"F.","full_name":"Vernuccio, F.","last_name":"Vernuccio"},{"last_name":"Spychala","first_name":"K. J.","full_name":"Spychala, K. J."},{"first_name":"R.","full_name":"Buschbeck, R.","last_name":"Buschbeck"},{"last_name":"Cerullo","full_name":"Cerullo, G.","first_name":"G."},{"last_name":"Polli","full_name":"Polli, D.","first_name":"D."},{"full_name":"Eng, L. M.","first_name":"L. M.","last_name":"Eng"}],"intvolume":" 112","citation":{"ama":"Hempel F, Rüsing M, Vernuccio F, et al. Phonon dephasing times determined with time-delayed broadband coherent anti-Stokes Raman scattering. Physical Review B. 2025;112(22). doi:10.1103/1ctr-csjy","apa":"Hempel, F., Rüsing, M., Vernuccio, F., Spychala, K. J., Buschbeck, R., Cerullo, G., Polli, D., & Eng, L. M. (2025). Phonon dephasing times determined with time-delayed broadband coherent anti-Stokes Raman scattering. Physical Review B, 112(22), Article 224106. https://doi.org/10.1103/1ctr-csjy","chicago":"Hempel, F., Michael Rüsing, F. Vernuccio, K. J. Spychala, R. Buschbeck, G. Cerullo, D. Polli, and L. M. Eng. “Phonon Dephasing Times Determined with Time-Delayed Broadband Coherent Anti-Stokes Raman Scattering.” Physical Review B 112, no. 22 (2025). https://doi.org/10.1103/1ctr-csjy.","ieee":"F. Hempel et al., “Phonon dephasing times determined with time-delayed broadband coherent anti-Stokes Raman scattering,” Physical Review B, vol. 112, no. 22, Art. no. 224106, 2025, doi: 10.1103/1ctr-csjy.","mla":"Hempel, F., et al. “Phonon Dephasing Times Determined with Time-Delayed Broadband Coherent Anti-Stokes Raman Scattering.” Physical Review B, vol. 112, no. 22, 224106, American Physical Society (APS), 2025, doi:10.1103/1ctr-csjy.","bibtex":"@article{Hempel_Rüsing_Vernuccio_Spychala_Buschbeck_Cerullo_Polli_Eng_2025, title={Phonon dephasing times determined with time-delayed broadband coherent anti-Stokes Raman scattering}, volume={112}, DOI={10.1103/1ctr-csjy}, number={22224106}, journal={Physical Review B}, publisher={American Physical Society (APS)}, author={Hempel, F. and Rüsing, Michael and Vernuccio, F. and Spychala, K. J. and Buschbeck, R. and Cerullo, G. and Polli, D. and Eng, L. M.}, year={2025} }","short":"F. Hempel, M. Rüsing, F. Vernuccio, K.J. Spychala, R. Buschbeck, G. Cerullo, D. Polli, L.M. Eng, Physical Review B 112 (2025)."},"publication_status":"published","department":[{"_id":"15"},{"_id":"623"},{"_id":"288"}],"quality_controlled":"1","publication":"Physical Review B","type":"journal_article","volume":112,"article_number":"224106","issue":"22","title":"Phonon dephasing times determined with time-delayed broadband coherent anti-Stokes Raman scattering","doi":"10.1103/1ctr-csjy","abstract":[{"lang":"eng","text":"Coherent Raman scattering techniques as coherent anti-Stokes Raman scattering (CARS), offer significant advantages in terms of pixel dwell times and speed as compared to spontaneous Raman scattering for investigations of crystalline materials. However, the spectral information in CARS is often hampered by the presence of a nonresonant contribution to the scattering process that shifts and distorts the Raman peaks. In this work, we apply a method to obtain nonresonant background-free spectra based on time-delayed, broadband CARS (TD-BCARS) using an intrapulse excitation scheme. In particular, this method can measure the phononic dephasing times across the full phonon spectrum at once. We test the methodology on amorphous SiO2 (glass), which is used to characterize the setup-specific and material-independent response times, and then apply TD-BCARS to the analysis of single crystals of diamond and ferroelectrics of potassium titanyl phosphate (KTP) and potassium titanyl arsenate (KTA). For diamond, we determine a dephasing time of 𝜏=7.81 ps for the single 𝑠𝑝3 peak."}],"main_file_link":[{"url":"https://arxiv.org/abs/2506.05519","open_access":"1"}],"oa":"1","user_id":"22501","external_id":{"arxiv":["2506.05519"]}},{"author":[{"last_name":"Sena","full_name":"Sena, Matheus","first_name":"Matheus"},{"first_name":"Mael","full_name":"Flament, Mael","last_name":"Flament"},{"full_name":"Andrewski, Shane","first_name":"Shane","last_name":"Andrewski"},{"last_name":"Caltzidis","full_name":"Caltzidis, Ioannis","first_name":"Ioannis"},{"last_name":"Bigagli","first_name":"Niccolò","full_name":"Bigagli, Niccolò"},{"last_name":"Rieser","full_name":"Rieser, Thomas","first_name":"Thomas"},{"last_name":"Bello Portmann","full_name":"Bello Portmann, Gabriel","first_name":"Gabriel"},{"last_name":"Sekelsky","first_name":"Rourke","full_name":"Sekelsky, Rourke"},{"last_name":"Braun","full_name":"Braun, Ralf-Peter","first_name":"Ralf-Peter"},{"last_name":"Craddock","full_name":"Craddock, Alexander N.","first_name":"Alexander N."},{"first_name":"Maximilian","full_name":"Schulz, Maximilian","last_name":"Schulz"},{"first_name":"Klaus","full_name":"Jöns, Klaus","last_name":"Jöns","id":"85353"},{"last_name":"Ritter","full_name":"Ritter, Michaela","first_name":"Michaela"},{"last_name":"Geitz","full_name":"Geitz, Marc","first_name":"Marc"},{"last_name":"Holschke","first_name":"Oliver","full_name":"Holschke, Oliver"},{"last_name":"Namazi","full_name":"Namazi, Mehdi","first_name":"Mehdi"}],"title":"High-fidelity quantum entanglement distribution in metropolitan fiber networks with co-propagating classical traffic","doi":"10.1364/jocn.575396","intvolume":" 17","abstract":[{"lang":"eng","text":"\r\n The Quantum Internet, a network of quantum-enabled infrastructure, represents the next frontier in telecommunications, promising capabilities that cannot be attained by classical counterparts. A crucial step in realizing such large-scale quantum networks is the integration of entanglement distribution within existing telecommunication infrastructure. Here, we demonstrate a real-world scalable quantum networking testbed deployed within Deutsche Telekom’s metropolitan fibers in Berlin. Using commercially available quantum devices and standard add-drop multiplexing hardware, we distributed polarization-entangled photon pairs over dynamically selectable looped fiber paths ranging from 10 m to 60 km and showed entanglement distribution over up to approximately 100 km. Quantum signals, transmitted at 1324 nm (O-band), coexist with conventional bidirectional C-band traffic without dedicated fibers or infrastructure changes. Active stabilization of the polarization enables robust long-term performance, achieving entanglement Bell-state fidelity bounds between 85% and 99% and Clauser–Horne–Shimony–Holt parameter\r\n S\r\n -values between 2.36 and 2.74 during continuous multiday operation. By achieving a high-fidelity entanglement distribution with less than 1.5% downtime, we confirm the feasibility of hybrid quantum-classical networks under real-world conditions at the metropolitan scale. These results establish deployment benchmarks and provide a practical roadmap for telecom operators to integrate quantum capabilities.\r\n "}],"publication_status":"published","user_id":"85353","citation":{"mla":"Sena, Matheus, et al. “High-Fidelity Quantum Entanglement Distribution in Metropolitan Fiber Networks with Co-Propagating Classical Traffic.” Journal of Optical Communications and Networking, vol. 17, no. 12, 1072, Optica Publishing Group, 2025, doi:10.1364/jocn.575396.","ama":"Sena M, Flament M, Andrewski S, et al. High-fidelity quantum entanglement distribution in metropolitan fiber networks with co-propagating classical traffic. Journal of Optical Communications and Networking. 2025;17(12). doi:10.1364/jocn.575396","bibtex":"@article{Sena_Flament_Andrewski_Caltzidis_Bigagli_Rieser_Bello Portmann_Sekelsky_Braun_Craddock_et al._2025, title={High-fidelity quantum entanglement distribution in metropolitan fiber networks with co-propagating classical traffic}, volume={17}, DOI={10.1364/jocn.575396}, number={121072}, journal={Journal of Optical Communications and Networking}, publisher={Optica Publishing Group}, author={Sena, Matheus and Flament, Mael and Andrewski, Shane and Caltzidis, Ioannis and Bigagli, Niccolò and Rieser, Thomas and Bello Portmann, Gabriel and Sekelsky, Rourke and Braun, Ralf-Peter and Craddock, Alexander N. and et al.}, year={2025} }","apa":"Sena, M., Flament, M., Andrewski, S., Caltzidis, I., Bigagli, N., Rieser, T., Bello Portmann, G., Sekelsky, R., Braun, R.-P., Craddock, A. N., Schulz, M., Jöns, K., Ritter, M., Geitz, M., Holschke, O., & Namazi, M. (2025). High-fidelity quantum entanglement distribution in metropolitan fiber networks with co-propagating classical traffic. Journal of Optical Communications and Networking, 17(12), Article 1072. https://doi.org/10.1364/jocn.575396","chicago":"Sena, Matheus, Mael Flament, Shane Andrewski, Ioannis Caltzidis, Niccolò Bigagli, Thomas Rieser, Gabriel Bello Portmann, et al. “High-Fidelity Quantum Entanglement Distribution in Metropolitan Fiber Networks with Co-Propagating Classical Traffic.” Journal of Optical Communications and Networking 17, no. 12 (2025). https://doi.org/10.1364/jocn.575396.","short":"M. Sena, M. Flament, S. Andrewski, I. Caltzidis, N. Bigagli, T. Rieser, G. Bello Portmann, R. Sekelsky, R.-P. Braun, A.N. Craddock, M. Schulz, K. Jöns, M. Ritter, M. Geitz, O. Holschke, M. Namazi, Journal of Optical Communications and Networking 17 (2025).","ieee":"M. Sena et al., “High-fidelity quantum entanglement distribution in metropolitan fiber networks with co-propagating classical traffic,” Journal of Optical Communications and Networking, vol. 17, no. 12, Art. no. 1072, 2025, doi: 10.1364/jocn.575396."},"department":[{"_id":"623"},{"_id":"15"}],"publisher":"Optica Publishing Group","date_created":"2025-12-04T12:20:01Z","publication":"Journal of Optical Communications and Networking","status":"public","language":[{"iso":"eng"}],"publication_identifier":{"issn":["1943-0620","1943-0639"]},"year":"2025","type":"journal_article","volume":17,"_id":"62860","issue":"12","date_updated":"2025-12-04T13:37:02Z","article_number":"1072"},{"publisher":"American Physical Society (APS)","date_created":"2025-12-05T09:33:36Z","publication":"Physical Review Research","status":"public","language":[{"iso":"eng"}],"type":"journal_article","publication_identifier":{"issn":["2643-1564"]},"year":"2025","volume":7,"_id":"62911","issue":"3","date_updated":"2025-12-05T09:55:22Z","article_number":"033122","author":[{"last_name":"Kopylov","first_name":"Denis A.","full_name":"Kopylov, Denis A."},{"full_name":"Stefszky, Michael","first_name":"Michael","last_name":"Stefszky","id":"42777"},{"last_name":"Meier","id":"344","first_name":"Torsten","full_name":"Meier, Torsten","orcid":"0000-0001-8864-2072"},{"full_name":"Silberhorn, Christine","first_name":"Christine","last_name":"Silberhorn","id":"26263"},{"last_name":"Sharapova","id":"60286","full_name":"Sharapova, Polina R.","first_name":"Polina R."}],"title":"Spectral and temporal properties of type-II parametric down-conversion: The impact of losses during state generation","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."}],"doi":"10.1103/zp72-7qwl","intvolume":" 7","project":[{"_id":"266","name":"PhoQC: Photonisches Quantencomputing"},{"_id":"53","name":"TRR 142: Maßgeschneiderte nichtlineare Photonik: Von grundlegenden Konzepten zu funktionellen Strukturen"},{"name":"TRR 142 - Project Area C","_id":"56"},{"name":"TRR 142 ; TP: C10: Erzeugung und Charakterisierung von Quantenlicht in nichtlinearen Systemen: Eine theoretische Analyse","_id":"174"}],"publication_status":"published","user_id":"16199","citation":{"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.","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","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","short":"D.A. Kopylov, M. Stefszky, T. Meier, C. Silberhorn, P.R. Sharapova, Physical Review Research 7 (2025).","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.","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} }"},"department":[{"_id":"15"},{"_id":"569"},{"_id":"170"},{"_id":"293"},{"_id":"288"},{"_id":"230"},{"_id":"623"},{"_id":"429"},{"_id":"35"}]},{"author":[{"full_name":"Hunstig, Anna","first_name":"Anna","id":"73659","last_name":"Hunstig"},{"first_name":"Sebastian","full_name":"Peitz, Sebastian","id":"47427","last_name":"Peitz","orcid":"0000-0002-3389-793X"},{"orcid":"0000-0002-3079-5428","first_name":"Hendrik","full_name":"Rose, Hendrik","id":"55958","last_name":"Rose"},{"orcid":"0000-0001-8864-2072","first_name":"Torsten","full_name":"Meier, Torsten","id":"344","last_name":"Meier"}],"title":"Accelerating the analysis of optical quantum systems using the Koopman operator","doi":"10.1109/cdc56724.2024.10886589","project":[{"name":"PhoQC: Photonisches Quantencomputing","_id":"266"}],"user_id":"16199","publication_status":"published","citation":{"apa":"Hunstig, A., Peitz, S., Rose, H., & Meier, T. (2025). Accelerating the analysis of optical quantum systems using the Koopman operator. 2024 IEEE 63rd Conference on Decision and Control (CDC). https://doi.org/10.1109/cdc56724.2024.10886589","ama":"Hunstig A, Peitz S, Rose H, Meier T. Accelerating the analysis of optical quantum systems using the Koopman operator. In: 2024 IEEE 63rd Conference on Decision and Control (CDC). IEEE; 2025. doi:10.1109/cdc56724.2024.10886589","bibtex":"@inproceedings{Hunstig_Peitz_Rose_Meier_2025, title={Accelerating the analysis of optical quantum systems using the Koopman operator}, DOI={10.1109/cdc56724.2024.10886589}, booktitle={2024 IEEE 63rd Conference on Decision and Control (CDC)}, publisher={IEEE}, author={Hunstig, Anna and Peitz, Sebastian and Rose, Hendrik and Meier, Torsten}, year={2025} }","mla":"Hunstig, Anna, et al. “Accelerating the Analysis of Optical Quantum Systems Using the Koopman Operator.” 2024 IEEE 63rd Conference on Decision and Control (CDC), IEEE, 2025, doi:10.1109/cdc56724.2024.10886589.","ieee":"A. Hunstig, S. Peitz, H. Rose, and T. Meier, “Accelerating the analysis of optical quantum systems using the Koopman operator,” 2025, doi: 10.1109/cdc56724.2024.10886589.","chicago":"Hunstig, Anna, Sebastian Peitz, Hendrik Rose, and Torsten Meier. “Accelerating the Analysis of Optical Quantum Systems Using the Koopman Operator.” In 2024 IEEE 63rd Conference on Decision and Control (CDC). IEEE, 2025. https://doi.org/10.1109/cdc56724.2024.10886589.","short":"A. Hunstig, S. Peitz, H. Rose, T. Meier, in: 2024 IEEE 63rd Conference on Decision and Control (CDC), IEEE, 2025."},"department":[{"_id":"15"},{"_id":"170"},{"_id":"293"},{"_id":"230"},{"_id":"623"},{"_id":"35"}],"publisher":"IEEE","publication":"2024 IEEE 63rd Conference on Decision and Control (CDC)","date_created":"2025-12-05T09:37:58Z","status":"public","type":"conference","year":"2025","language":[{"iso":"eng"}],"_id":"62913","date_updated":"2025-12-05T09:40:24Z"},{"publisher":"American Physical Society (APS)","date_created":"2025-12-09T09:08:39Z","status":"public","language":[{"iso":"eng"}],"publication_identifier":{"issn":["2643-1564"]},"year":"2025","_id":"62980","date_updated":"2025-12-09T09:10:01Z","author":[{"first_name":"Denis A.","full_name":"Kopylov, Denis A.","last_name":"Kopylov"},{"id":"85279","last_name":"Offen","first_name":"Christian","full_name":"Offen, Christian","orcid":"0000-0002-5940-8057"},{"full_name":"Ares, Laura","first_name":"Laura","last_name":"Ares"},{"id":"95394","last_name":"Wembe Moafo","full_name":"Wembe Moafo, Boris Edgar","first_name":"Boris Edgar"},{"last_name":"Ober-Blöbaum","id":"16494","full_name":"Ober-Blöbaum, Sina","first_name":"Sina"},{"orcid":"0000-0001-8864-2072","id":"344","last_name":"Meier","full_name":"Meier, Torsten","first_name":"Torsten"},{"first_name":"Polina R.","full_name":"Sharapova, Polina R.","last_name":"Sharapova","id":"60286"},{"first_name":"Jan","full_name":"Sperling, Jan","id":"75127","last_name":"Sperling","orcid":"0000-0002-5844-3205"}],"intvolume":" 7","publication_status":"published","citation":{"bibtex":"@article{Kopylov_Offen_Ares_Wembe Moafo_Ober-Blöbaum_Meier_Sharapova_Sperling_2025, title={Multiphoton, multimode state classification for nonlinear optical circuits}, volume={7}, DOI={10.1103/sv6z-v1gk}, number={3033062}, journal={Physical Review Research}, publisher={American Physical Society (APS)}, author={Kopylov, Denis A. and Offen, Christian and Ares, Laura and Wembe Moafo, Boris Edgar and Ober-Blöbaum, Sina and Meier, Torsten and Sharapova, Polina R. and Sperling, Jan}, year={2025} }","mla":"Kopylov, Denis A., et al. “Multiphoton, Multimode State Classification for Nonlinear Optical Circuits.” Physical Review Research, vol. 7, no. 3, 033062, American Physical Society (APS), 2025, doi:10.1103/sv6z-v1gk.","short":"D.A. Kopylov, C. Offen, L. Ares, B.E. Wembe Moafo, S. Ober-Blöbaum, T. Meier, P.R. Sharapova, J. Sperling, Physical Review Research 7 (2025).","apa":"Kopylov, D. A., Offen, C., Ares, L., Wembe Moafo, B. E., Ober-Blöbaum, S., Meier, T., Sharapova, P. R., & Sperling, J. (2025). Multiphoton, multimode state classification for nonlinear optical circuits. Physical Review Research, 7(3), Article 033062. https://doi.org/10.1103/sv6z-v1gk","ama":"Kopylov DA, Offen C, Ares L, et al. Multiphoton, multimode state classification for nonlinear optical circuits. Physical Review Research. 2025;7(3). doi:10.1103/sv6z-v1gk","ieee":"D. A. Kopylov et al., “Multiphoton, multimode state classification for nonlinear optical circuits,” Physical Review Research, vol. 7, no. 3, Art. no. 033062, 2025, doi: 10.1103/sv6z-v1gk.","chicago":"Kopylov, Denis A., Christian Offen, Laura Ares, Boris Edgar Wembe Moafo, Sina Ober-Blöbaum, Torsten Meier, Polina R. Sharapova, and Jan Sperling. “Multiphoton, Multimode State Classification for Nonlinear Optical Circuits.” Physical Review Research 7, no. 3 (2025). https://doi.org/10.1103/sv6z-v1gk."},"department":[{"_id":"15"},{"_id":"569"},{"_id":"170"},{"_id":"293"},{"_id":"706"},{"_id":"636"},{"_id":"35"},{"_id":"230"},{"_id":"429"},{"_id":"623"}],"publication":"Physical Review Research","type":"journal_article","volume":7,"issue":"3","article_number":"033062","title":"Multiphoton, multimode state classification for nonlinear optical circuits","doi":"10.1103/sv6z-v1gk","abstract":[{"lang":"eng","text":"We introduce a new classification of multimode states with a fixed number of photons. This classification is based on the factorizability of homogeneous multivariate polynomials and is invariant under unitary transformations. The classes physically correspond to field excitations in terms of single and multiple photons, each of which is in an arbitrary irreducible superposition of quantized modes. We further show how the transitions between classes are rendered possible by photon addition, photon subtraction, and photon-projection nonlinearities. We explicitly put forward a design for a multilayer interferometer in which the states for different classes can be generated with state-of-the-art experimental techniques. Limitations of the proposed designs are analyzed using the introduced classification, providing a benchmark for the robustness of certain states and classes."}],"project":[{"name":"TRR 142: Maßgeschneiderte nichtlineare Photonik: Von grundlegenden Konzepten zu funktionellen Strukturen","_id":"53"},{"name":"TRR 142 - Project Area C","_id":"56"},{"name":"TRR 142 ; TP: C10: Erzeugung und Charakterisierung von Quantenlicht in nichtlinearen Systemen: Eine theoretische Analyse","_id":"174"},{"_id":"266","name":"PhoQC: Photonisches Quantencomputing"}],"user_id":"16199"},{"title":"Multiphoton, multimode state classification for nonlinear optical circuits","author":[{"orcid":"0000-0001-8864-2072","first_name":"Torsten","full_name":"Meier, Torsten","last_name":"Meier","id":"344"},{"full_name":"Sharapova, Polina R.","first_name":"Polina R.","id":"60286","last_name":"Sharapova"},{"first_name":"Jan","full_name":"Sperling, Jan","id":"75127","last_name":"Sperling","orcid":"0000-0002-5844-3205"},{"id":"16494","last_name":"Ober-Blöbaum","first_name":"Sina","full_name":"Ober-Blöbaum, Sina"},{"id":"95394","last_name":"Wembe Moafo","first_name":"Boris Edgar","full_name":"Wembe Moafo, Boris Edgar"},{"last_name":"Offen","id":"85279","first_name":"Christian","full_name":"Offen, Christian","orcid":"0000-0002-5940-8057"}],"project":[{"_id":"53","name":"TRR 142: Maßgeschneiderte nichtlineare Photonik: Von grundlegenden Konzepten zu funktionellen Strukturen"},{"_id":"56","name":"TRR 142 - Project Area C"},{"name":"TRR 142 ; TP: C10: Erzeugung und Charakterisierung von Quantenlicht in nichtlinearen Systemen: Eine theoretische Analyse","_id":"174"},{"_id":"266","name":"PhoQC: Photonisches Quantencomputing"}],"abstract":[{"lang":"eng","text":"We introduce a new classification of multimode states with a fixed number of photons. This classification is based on the factorizability of homogeneous multivariate polynomials and is invariant under unitary transformations. The classes physically correspond to field excitations in terms of single and multiple photons, each of which being in an arbitrary irreducible superposition of quantized modes. We further show how the transitions between classes are rendered possible by photon addition, photon subtraction, and photon-projection nonlinearities. We explicitly put forward a design for a multilayer interferometer in which the states for different classes can be generated with state-of-the-art experimental techniques. Limitations of the proposed designs are analyzed using the introduced classification, providing a benchmark for the robustness of certain states and classes."}],"citation":{"short":"T. Meier, P.R. Sharapova, J. Sperling, S. Ober-Blöbaum, B.E. Wembe Moafo, C. Offen, (2025).","chicago":"Meier, Torsten, Polina R. Sharapova, Jan Sperling, Sina Ober-Blöbaum, Boris Edgar Wembe Moafo, and Christian Offen. “Multiphoton, Multimode State Classification for Nonlinear Optical Circuits,” 2025.","ieee":"T. Meier, P. R. Sharapova, J. Sperling, S. Ober-Blöbaum, B. E. Wembe Moafo, and C. Offen, “Multiphoton, multimode state classification for nonlinear optical circuits.” 2025.","mla":"Meier, Torsten, et al. Multiphoton, Multimode State Classification for Nonlinear Optical Circuits. 2025.","ama":"Meier T, Sharapova PR, Sperling J, Ober-Blöbaum S, Wembe Moafo BE, Offen C. Multiphoton, multimode state classification for nonlinear optical circuits. Published online 2025.","bibtex":"@article{Meier_Sharapova_Sperling_Ober-Blöbaum_Wembe Moafo_Offen_2025, title={Multiphoton, multimode state classification for nonlinear optical circuits}, author={Meier, Torsten and Sharapova, Polina R. and Sperling, Jan and Ober-Blöbaum, Sina and Wembe Moafo, Boris Edgar and Offen, Christian}, year={2025} }","apa":"Meier, T., Sharapova, P. R., Sperling, J., Ober-Blöbaum, S., Wembe Moafo, B. E., & Offen, C. (2025). Multiphoton, multimode state classification for nonlinear optical circuits."},"user_id":"16199","department":[{"_id":"15"},{"_id":"170"},{"_id":"293"},{"_id":"706"},{"_id":"636"},{"_id":"230"},{"_id":"623"},{"_id":"429"},{"_id":"35"}],"date_created":"2025-12-09T08:59:27Z","type":"preprint","year":"2025","language":[{"iso":"eng"}],"status":"public","_id":"62979","date_updated":"2025-12-09T09:10:23Z"},{"author":[{"last_name":"Bianchi","first_name":"Luca","full_name":"Bianchi, Luca"},{"full_name":"Marconi, Carlo","first_name":"Carlo","last_name":"Marconi"},{"orcid":"0000-0002-5844-3205","full_name":"Sperling, Jan","first_name":"Jan","last_name":"Sperling","id":"75127"},{"first_name":"Davide","full_name":"Bacco, Davide","last_name":"Bacco"}],"title":"Predetection squeezing as a resource for high-dimensional Bell-state measurements","intvolume":" 7","abstract":[{"text":"Bell measurements, entailing the projection onto one of the Bell states, play a key role in quantum information and communication, where the outcome of a variety of protocols crucially depends on the success probability of such measurements. Although in the case of qubit systems, Bell measurements can be implemented using only linear optical components, the same result is no longer true for qudits, where at least the use of ancillary photons is required. In order to circumvent this limitation, one possibility is to introduce nonlinear effects. In this work, we adopt the latter approach and propose a scalable Bell measurement scheme for high-dimensional states, exploiting multiple squeezer devices applied to a linear optical circuit for discriminating the different Bell states. Our approach does not require ancillary photons, is not limited by the dimension of the quantum states, and is experimentally scalable, thus paving the way toward the realization of an effective high-dimensional Bell measurement.","lang":"eng"}],"doi":"10.1103/physrevresearch.7.023038","publication_status":"published","user_id":"75127","citation":{"apa":"Bianchi, L., Marconi, C., Sperling, J., & Bacco, D. (2025). Predetection squeezing as a resource for high-dimensional Bell-state measurements. Physical Review Research, 7(2), Article 023038. https://doi.org/10.1103/physrevresearch.7.023038","ama":"Bianchi L, Marconi C, Sperling J, Bacco D. Predetection squeezing as a resource for high-dimensional Bell-state measurements. Physical Review Research. 2025;7(2). doi:10.1103/physrevresearch.7.023038","chicago":"Bianchi, Luca, Carlo Marconi, Jan Sperling, and Davide Bacco. “Predetection Squeezing as a Resource for High-Dimensional Bell-State Measurements.” Physical Review Research 7, no. 2 (2025). https://doi.org/10.1103/physrevresearch.7.023038.","ieee":"L. Bianchi, C. Marconi, J. Sperling, and D. Bacco, “Predetection squeezing as a resource for high-dimensional Bell-state measurements,” Physical Review Research, vol. 7, no. 2, Art. no. 023038, 2025, doi: 10.1103/physrevresearch.7.023038.","mla":"Bianchi, Luca, et al. “Predetection Squeezing as a Resource for High-Dimensional Bell-State Measurements.” Physical Review Research, vol. 7, no. 2, 023038, American Physical Society (APS), 2025, doi:10.1103/physrevresearch.7.023038.","bibtex":"@article{Bianchi_Marconi_Sperling_Bacco_2025, title={Predetection squeezing as a resource for high-dimensional Bell-state measurements}, volume={7}, DOI={10.1103/physrevresearch.7.023038}, number={2023038}, journal={Physical Review Research}, publisher={American Physical Society (APS)}, author={Bianchi, Luca and Marconi, Carlo and Sperling, Jan and Bacco, Davide}, year={2025} }","short":"L. Bianchi, C. Marconi, J. Sperling, D. Bacco, Physical Review Research 7 (2025)."},"department":[{"_id":"623"},{"_id":"15"},{"_id":"170"},{"_id":"706"},{"_id":"429"}],"publisher":"American Physical Society (APS)","date_created":"2025-12-10T13:34:53Z","publication":"Physical Review Research","status":"public","language":[{"iso":"eng"}],"publication_identifier":{"issn":["2643-1564"]},"type":"journal_article","year":"2025","volume":7,"_id":"63021","issue":"2","date_updated":"2025-12-10T13:36:11Z","article_number":"023038"},{"intvolume":" 7","author":[{"first_name":"Santiago","full_name":"Bermúdez-Feijóo, Santiago","last_name":"Bermúdez-Feijóo"},{"last_name":"Zubizarreta Casalengua","first_name":"Eduardo","full_name":"Zubizarreta Casalengua, Eduardo"},{"last_name":"Müller","first_name":"Kai","full_name":"Müller, Kai"},{"full_name":"Jöns, Klaus","first_name":"Klaus","last_name":"Jöns","id":"85353"}],"department":[{"_id":"623"},{"_id":"15"},{"_id":"429"},{"_id":"642"}],"publication_status":"published","citation":{"mla":"Bermúdez-Feijóo, Santiago, et al. “Spectral Correlations of Dynamical Resonance Fluorescence.” Physical Review Research, vol. 7, no. 3, 033296, American Physical Society (APS), 2025, doi:10.1103/jmy9-bd3l.","ama":"Bermúdez-Feijóo S, Zubizarreta Casalengua E, Müller K, Jöns K. Spectral correlations of dynamical resonance fluorescence. Physical Review Research. 2025;7(3). doi:10.1103/jmy9-bd3l","bibtex":"@article{Bermúdez-Feijóo_Zubizarreta Casalengua_Müller_Jöns_2025, title={Spectral correlations of dynamical resonance fluorescence}, volume={7}, DOI={10.1103/jmy9-bd3l}, number={3033296}, journal={Physical Review Research}, publisher={American Physical Society (APS)}, author={Bermúdez-Feijóo, Santiago and Zubizarreta Casalengua, Eduardo and Müller, Kai and Jöns, Klaus}, year={2025} }","apa":"Bermúdez-Feijóo, S., Zubizarreta Casalengua, E., Müller, K., & Jöns, K. (2025). Spectral correlations of dynamical resonance fluorescence. Physical Review Research, 7(3), Article 033296. https://doi.org/10.1103/jmy9-bd3l","chicago":"Bermúdez-Feijóo, Santiago, Eduardo Zubizarreta Casalengua, Kai Müller, and Klaus Jöns. “Spectral Correlations of Dynamical Resonance Fluorescence.” Physical Review Research 7, no. 3 (2025). https://doi.org/10.1103/jmy9-bd3l.","short":"S. Bermúdez-Feijóo, E. Zubizarreta Casalengua, K. Müller, K. Jöns, Physical Review Research 7 (2025).","ieee":"S. Bermúdez-Feijóo, E. Zubizarreta Casalengua, K. Müller, and K. Jöns, “Spectral correlations of dynamical resonance fluorescence,” Physical Review Research, vol. 7, no. 3, Art. no. 033296, 2025, doi: 10.1103/jmy9-bd3l."},"status":"public","publication_identifier":{"issn":["2643-1564"]},"year":"2025","language":[{"iso":"eng"}],"publisher":"American Physical Society (APS)","date_created":"2025-12-04T12:19:04Z","date_updated":"2025-12-11T12:52:24Z","_id":"62859","abstract":[{"text":"Frequency-filtered photon correlations have been proven to be extremely useful in grasping how the detection process alters photon statistics. Harnessing the spectral correlations also permits refinement of the emission and unraveling of previously hidden strong correlations in a plethora of quantum-optical systems under continuous-wave excitation. In this work, we investigate such correlations for time-dependent excitation and develop a methodology to compute efficiently time-integrated correlations, which are at the heart of the photon-counting theory, and subsequently apply it to analyze the photon emission of pulsed systems. By combining this formalism with the —which facilitates frequency-resolved correlations—we demonstrate how spectral filtering enhances single-photon purity and suppresses multiphoton noise in time-bin-encoded quantum states. Specifically, filtering the central spectral peak of a dynamically driven two-level system boosts temporal coherence and improves the fidelity of time-bin entanglement preparation, even under conditions favoring multiphoton emission. These results establish spectral filtering as a critical tool for tailoring photon statistics in pulsed quantum light sources.","lang":"eng"}],"doi":"10.1103/jmy9-bd3l","title":"Spectral correlations of dynamical resonance fluorescence","user_id":"48188","type":"journal_article","publication":"Physical Review Research","issue":"3","article_number":"033296","volume":7}]