--- _id: '62752' abstract: - lang: eng text: In higher education, assessment/examination procedures should be designed to form a coherent learning process that is aligned with the intended learning objectives and planned learning activities. However, in academic teacher education programmes often use assessment formats that are not well aligned with the demands of teachers' actual professional practice. Performance-based assessments can offer an alternative, for example in the form of role-play-based simulations with trained actors representing typical professional activities in environments of reduced complexity. We have developed such a performance-based assessment format for physics teacher education, analogous to the Objective Structured Teaching Examinations (OSTE) approach used in medical education. The OSTE prototype consists of seven short simulative assessments, reflecting four areas of competence (Instruction, Assessment, Pedagogy and Innovation) that form a 90-minute examination course. In order to investigate prospective physics teachers' perceptions of such an assessment format in terms of its suitability as a summative examination procedure, we piloted the OSTE prototype with N = 34 physics student teachers from three German universities using short questionnaires. The results show that participants perceived the OSTE prototype as authentic and relevant, but they also highlight the need for adequate new learning opportunities to prepare for such simulative examinations to be integrated into teacher education programmes. author: - first_name: Christoph full_name: Vogelsang, Christoph id: '4245' last_name: Vogelsang orcid: 0000-0002-5804-1855 - first_name: Lea full_name: Grotegut, Lea id: '34280' last_name: Grotegut - first_name: Philipp full_name: Wotschel, Philipp id: '89529' last_name: Wotschel - first_name: Thomas full_name: Janzen, Thomas id: '89329' last_name: Janzen orcid: 0009-0003-1941-166X citation: ama: 'Vogelsang C, Grotegut L, Wotschel P, Janzen T. Prospective Physics Teachers’  Perceptions of an Objective Structured  Teaching Examination (OSTE). In: ; 2025.' apa: Vogelsang, C., Grotegut, L., Wotschel, P., & Janzen, T. (2025). Prospective Physics Teachers’  Perceptions of an Objective Structured  Teaching Examination (OSTE). ESERA 2025 Conference, Copenhagen. bibtex: '@inproceedings{Vogelsang_Grotegut_Wotschel_Janzen_2025, place={Copenhagen}, title={Prospective Physics Teachers’  Perceptions of an Objective Structured  Teaching Examination (OSTE)}, author={Vogelsang, Christoph and Grotegut, Lea and Wotschel, Philipp and Janzen, Thomas}, year={2025} }' chicago: Vogelsang, Christoph, Lea Grotegut, Philipp Wotschel, and Thomas Janzen. “Prospective Physics Teachers’  Perceptions of an Objective Structured  Teaching Examination (OSTE).” Copenhagen, 2025. ieee: C. Vogelsang, L. Grotegut, P. Wotschel, and T. Janzen, “Prospective Physics Teachers’  Perceptions of an Objective Structured  Teaching Examination (OSTE),” presented at the ESERA 2025 Conference, Copenhagen, 2025. mla: Vogelsang, Christoph, et al. Prospective Physics Teachers’  Perceptions of an Objective Structured  Teaching Examination (OSTE). 2025. short: 'C. Vogelsang, L. Grotegut, P. Wotschel, T. Janzen, in: Copenhagen, 2025.' conference: end_date: 2025-08-30 location: Copenhagen name: ESERA 2025 Conference start_date: 2025-08-25 date_created: 2025-12-03T08:43:26Z date_updated: 2025-12-03T08:56:29Z department: - _id: '33' keyword: - teacher education - physics - assessment - pre-service teachers language: - iso: eng place: Copenhagen quality_controlled: '1' status: public title: Prospective Physics Teachers' Perceptions of an Objective Structured Teaching Examination (OSTE) type: conference user_id: '4245' year: '2025' ... --- _id: '51156' abstract: - lang: eng text: 'Ferroelectric domain wall (DW) conductivity (DWC) can be attributed to two separate mechanisms: (a) the injection/ejection of charge carriers across the Schottky barrier formed at the (metal-)electrode-DW junction and (b) the transport of those charge carriers along the DW. Current-voltage (I-U) characteristics, recorded at variable temperatures from LiNbO3 (LNO) DWs, are clearly able to differentiate between these two contributions. Practically, they allow us to directly quantify the physical parameters relevant to the two mechanisms (a) and (b) mentioned above. These are, for example, the resistance of the DW, the saturation current, the ideality factor, and the Schottky barrier height of the electrode-DW junction. Furthermore, the activation energies needed to initiate the thermally activated electronic transport along the DWs can be extracted. In addition, we show that electronic transport along LNO DWs can be elegantly viewed and interpreted in an adapted semiconductor picture based on a double-diode, double-resistor equivalent-circuit model, the R2D2 model. Finally, our R2D2 model was checked for its universality by successfully fitting the I-U curves of not only z-cut LNO bulk DWs, but equally of z-cut thin-film LNO DWs, and of x-cut thin-film DWs as reported in literature.' article_number: '024007' article_type: original author: - first_name: Manuel full_name: Zahn, Manuel last_name: Zahn - first_name: Elke full_name: Beyreuther, Elke last_name: Beyreuther - first_name: Iuliia full_name: Kiseleva, Iuliia last_name: Kiseleva - first_name: Ahmed Samir full_name: Lotfy, Ahmed Samir last_name: Lotfy - first_name: Conor J. full_name: McCluskey, Conor J. last_name: McCluskey - first_name: Jesi R. full_name: Maguire, Jesi R. last_name: Maguire - first_name: Ahmet full_name: Suna, Ahmet last_name: Suna - first_name: Michael full_name: Rüsing, Michael id: '22501' last_name: Rüsing orcid: 0000-0003-4682-4577 - first_name: J. Marty full_name: Gregg, J. Marty last_name: Gregg - first_name: Lukas M. full_name: Eng, Lukas M. last_name: Eng citation: ama: Zahn M, Beyreuther E, Kiseleva I, et al. Equivalent-circuit model that quantitatively describes domain-wall conductivity in ferroelectric lithium . Physical Review Applied. 2024;21(2). doi:10.1103/physrevapplied.21.024007 apa: Zahn, M., Beyreuther, E., Kiseleva, I., Lotfy, A. S., McCluskey, C. J., Maguire, J. R., Suna, A., Rüsing, M., Gregg, J. M., & Eng, L. M. (2024). Equivalent-circuit model that quantitatively describes domain-wall conductivity in ferroelectric lithium . Physical Review Applied, 21(2), Article 024007. https://doi.org/10.1103/physrevapplied.21.024007 bibtex: '@article{Zahn_Beyreuther_Kiseleva_Lotfy_McCluskey_Maguire_Suna_Rüsing_Gregg_Eng_2024, title={Equivalent-circuit model that quantitatively describes domain-wall conductivity in ferroelectric lithium }, volume={21}, DOI={10.1103/physrevapplied.21.024007}, number={2024007}, journal={Physical Review Applied}, publisher={American Physical Society (APS)}, author={Zahn, Manuel and Beyreuther, Elke and Kiseleva, Iuliia and Lotfy, Ahmed Samir and McCluskey, Conor J. and Maguire, Jesi R. and Suna, Ahmet and Rüsing, Michael and Gregg, J. Marty and Eng, Lukas M.}, year={2024} }' chicago: Zahn, Manuel, Elke Beyreuther, Iuliia Kiseleva, Ahmed Samir Lotfy, Conor J. McCluskey, Jesi R. Maguire, Ahmet Suna, Michael Rüsing, J. Marty Gregg, and Lukas M. Eng. “Equivalent-Circuit Model That Quantitatively Describes Domain-Wall Conductivity in Ferroelectric Lithium .” Physical Review Applied 21, no. 2 (2024). https://doi.org/10.1103/physrevapplied.21.024007. ieee: 'M. Zahn et al., “Equivalent-circuit model that quantitatively describes domain-wall conductivity in ferroelectric lithium ,” Physical Review Applied, vol. 21, no. 2, Art. no. 024007, 2024, doi: 10.1103/physrevapplied.21.024007.' mla: Zahn, Manuel, et al. “Equivalent-Circuit Model That Quantitatively Describes Domain-Wall Conductivity in Ferroelectric Lithium .” Physical Review Applied, vol. 21, no. 2, 024007, American Physical Society (APS), 2024, doi:10.1103/physrevapplied.21.024007. short: M. Zahn, E. Beyreuther, I. Kiseleva, A.S. Lotfy, C.J. McCluskey, J.R. Maguire, A. Suna, M. Rüsing, J.M. Gregg, L.M. Eng, Physical Review Applied 21 (2024). date_created: 2024-02-06T08:02:15Z date_updated: 2024-02-06T08:08:09Z department: - _id: '15' - _id: '169' - _id: '623' - _id: '288' doi: 10.1103/physrevapplied.21.024007 intvolume: ' 21' issue: '2' keyword: - General Physics and Astronomy language: - iso: eng main_file_link: - open_access: '1' url: https://arxiv.org/abs/2307.10322 oa: '1' publication: Physical Review Applied publication_identifier: issn: - 2331-7019 publication_status: published publisher: American Physical Society (APS) quality_controlled: '1' status: public title: 'Equivalent-circuit model that quantitatively describes domain-wall conductivity in ferroelectric lithium ' type: journal_article user_id: '22501' volume: 21 year: '2024' ... --- _id: '51221' abstract: - lang: eng text: Charge transfer mechanism in the deprotonation-induced n-type doping of PCBM. author: - first_name: Chuan-Ding full_name: Dong, Chuan-Ding id: '67188' last_name: Dong - first_name: Fabian full_name: Bauch, Fabian id: '61389' last_name: Bauch orcid: 0009-0008-6279-077X - first_name: Yuanyuan full_name: Hu, Yuanyuan last_name: Hu - first_name: Stefan full_name: Schumacher, Stefan id: '27271' last_name: Schumacher orcid: 0000-0003-4042-4951 citation: ama: Dong C-D, Bauch F, Hu Y, Schumacher S. Charge transfer in superbase n-type doping of PCBM induced by deprotonation. Physical Chemistry Chemical Physics. 2024;26(5):4194-4199. doi:10.1039/d3cp05105f apa: Dong, C.-D., Bauch, F., Hu, Y., & Schumacher, S. (2024). Charge transfer in superbase n-type doping of PCBM induced by deprotonation. Physical Chemistry Chemical Physics, 26(5), 4194–4199. https://doi.org/10.1039/d3cp05105f bibtex: '@article{Dong_Bauch_Hu_Schumacher_2024, title={Charge transfer in superbase n-type doping of PCBM induced by deprotonation}, volume={26}, DOI={10.1039/d3cp05105f}, number={5}, journal={Physical Chemistry Chemical Physics}, publisher={Royal Society of Chemistry (RSC)}, author={Dong, Chuan-Ding and Bauch, Fabian and Hu, Yuanyuan and Schumacher, Stefan}, year={2024}, pages={4194–4199} }' chicago: 'Dong, Chuan-Ding, Fabian Bauch, Yuanyuan Hu, and Stefan Schumacher. “Charge Transfer in Superbase N-Type Doping of PCBM Induced by Deprotonation.” Physical Chemistry Chemical Physics 26, no. 5 (2024): 4194–99. https://doi.org/10.1039/d3cp05105f.' ieee: 'C.-D. Dong, F. Bauch, Y. Hu, and S. Schumacher, “Charge transfer in superbase n-type doping of PCBM induced by deprotonation,” Physical Chemistry Chemical Physics, vol. 26, no. 5, pp. 4194–4199, 2024, doi: 10.1039/d3cp05105f.' mla: Dong, Chuan-Ding, et al. “Charge Transfer in Superbase N-Type Doping of PCBM Induced by Deprotonation.” Physical Chemistry Chemical Physics, vol. 26, no. 5, Royal Society of Chemistry (RSC), 2024, pp. 4194–99, doi:10.1039/d3cp05105f. short: C.-D. Dong, F. Bauch, Y. Hu, S. Schumacher, Physical Chemistry Chemical Physics 26 (2024) 4194–4199. date_created: 2024-02-07T14:15:44Z date_updated: 2024-02-07T14:35:55Z department: - _id: '35' - _id: '15' doi: 10.1039/d3cp05105f intvolume: ' 26' issue: '5' keyword: - Physical and Theoretical Chemistry - General Physics and Astronomy language: - iso: eng page: 4194-4199 publication: Physical Chemistry Chemical Physics publication_identifier: issn: - 1463-9076 - 1463-9084 publication_status: published publisher: Royal Society of Chemistry (RSC) status: public title: Charge transfer in superbase n-type doping of PCBM induced by deprotonation type: journal_article user_id: '61389' volume: 26 year: '2024' ... --- _id: '51339' author: - first_name: Jonas full_name: Babai-Hemati, Jonas last_name: Babai-Hemati - first_name: Felix full_name: vom Bruch, Felix id: '71245' last_name: vom Bruch - 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: Babai-Hemati J, vom Bruch F, Herrmann H, Silberhorn C. Tailored second harmonic generation inTi-diffused PPLN waveguides usingmicro-heaters. Optics Express. Published online 2024. doi:10.1364/oe.510319 apa: Babai-Hemati, J., vom Bruch, F., Herrmann, H., & Silberhorn, C. (2024). Tailored second harmonic generation inTi-diffused PPLN waveguides usingmicro-heaters. Optics Express. https://doi.org/10.1364/oe.510319 bibtex: '@article{Babai-Hemati_vom Bruch_Herrmann_Silberhorn_2024, title={Tailored second harmonic generation inTi-diffused PPLN waveguides usingmicro-heaters}, DOI={10.1364/oe.510319}, journal={Optics Express}, publisher={Optica Publishing Group}, author={Babai-Hemati, Jonas and vom Bruch, Felix and Herrmann, Harald and Silberhorn, Christine}, year={2024} }' chicago: Babai-Hemati, Jonas, Felix vom Bruch, Harald Herrmann, and Christine Silberhorn. “Tailored Second Harmonic Generation InTi-Diffused PPLN Waveguides Usingmicro-Heaters.” Optics Express, 2024. https://doi.org/10.1364/oe.510319. ieee: 'J. Babai-Hemati, F. vom Bruch, H. Herrmann, and C. Silberhorn, “Tailored second harmonic generation inTi-diffused PPLN waveguides usingmicro-heaters,” Optics Express, 2024, doi: 10.1364/oe.510319.' mla: Babai-Hemati, Jonas, et al. “Tailored Second Harmonic Generation InTi-Diffused PPLN Waveguides Usingmicro-Heaters.” Optics Express, Optica Publishing Group, 2024, doi:10.1364/oe.510319. short: J. Babai-Hemati, F. vom Bruch, H. Herrmann, C. Silberhorn, Optics Express (2024). date_created: 2024-02-13T13:03:01Z date_updated: 2024-02-13T13:09:51Z department: - _id: '15' - _id: '623' - _id: '288' doi: 10.1364/oe.510319 keyword: - Atomic and Molecular Physics - and Optics language: - iso: eng project: - _id: '266' grant_number: PROFILNRW-2020-067 name: 'PhoQC: PhoQC: Photonisches Quantencomputing' publication: Optics Express publication_identifier: issn: - 1094-4087 publication_status: published publisher: Optica Publishing Group status: public title: Tailored second harmonic generation inTi-diffused PPLN waveguides usingmicro-heaters type: journal_article user_id: '216' year: '2024' ... --- _id: '51519' author: - first_name: Tie Jun full_name: Cui, Tie Jun last_name: Cui - first_name: Shuang full_name: Zhang, Shuang last_name: Zhang - first_name: Andrea full_name: Alu, Andrea last_name: Alu - first_name: Martin full_name: Wegener, Martin last_name: Wegener - first_name: John full_name: Pendry, John last_name: Pendry - first_name: Jie full_name: Luo, Jie last_name: Luo - first_name: Yun full_name: Lai, Yun last_name: Lai - first_name: Zuojia full_name: Wang, Zuojia last_name: Wang - first_name: Xiao full_name: Lin, Xiao last_name: Lin - first_name: Hongsheng full_name: Chen, Hongsheng last_name: Chen - first_name: Ping full_name: Chen, Ping last_name: Chen - first_name: Rui-Xin full_name: Wu, Rui-Xin last_name: Wu - first_name: Yuhang full_name: Yin, Yuhang last_name: Yin - first_name: Pengfei full_name: Zhao, Pengfei last_name: Zhao - first_name: Huanyang full_name: Chen, Huanyang last_name: Chen - first_name: Yue full_name: Li, Yue last_name: Li - first_name: Ziheng full_name: Zhou, Ziheng last_name: Zhou - first_name: Nader full_name: Engheta, Nader last_name: Engheta - first_name: V. S. full_name: Asadchy, V. S. last_name: Asadchy - first_name: Constantin full_name: Simovski, Constantin last_name: Simovski - first_name: Sergei A full_name: Tretyakov, Sergei A last_name: Tretyakov - first_name: Biao full_name: Yang, Biao last_name: Yang - first_name: Sawyer D. full_name: Campbell, Sawyer D. last_name: Campbell - first_name: Yang full_name: Hao, Yang last_name: Hao - first_name: Douglas H full_name: Werner, Douglas H last_name: Werner - first_name: Shulin full_name: Sun, Shulin last_name: Sun - first_name: Lei full_name: Zhou, Lei last_name: Zhou - first_name: Su full_name: Xu, Su last_name: Xu - first_name: Hong-Bo full_name: Sun, Hong-Bo last_name: Sun - first_name: Zhou full_name: Zhou, Zhou last_name: Zhou - first_name: Zile full_name: Li, Zile last_name: Li - first_name: Guoxing full_name: Zheng, Guoxing last_name: Zheng - first_name: Xianzhong full_name: Chen, Xianzhong last_name: Chen - first_name: Tao full_name: Li, Tao last_name: Li - first_name: Shi-Ning full_name: Zhu, Shi-Ning last_name: Zhu - first_name: Junxiao full_name: Zhou, Junxiao last_name: Zhou - first_name: Junxiang full_name: Zhao, Junxiang last_name: Zhao - first_name: Zhaowei full_name: Liu, Zhaowei last_name: Liu - first_name: Yuchao full_name: Zhang, Yuchao last_name: Zhang - first_name: Qiming full_name: Zhang, Qiming last_name: Zhang - first_name: Min full_name: Gu, Min last_name: Gu - first_name: Shumin full_name: Xiao, Shumin last_name: Xiao - first_name: Yongmin full_name: Liu, Yongmin last_name: Liu - first_name: Xiaoyu full_name: Zhang, Xiaoyu last_name: Zhang - first_name: Yutao full_name: Tang, Yutao last_name: Tang - first_name: Guixin full_name: Li, Guixin last_name: Li - first_name: Thomas full_name: Zentgraf, Thomas id: '30525' last_name: Zentgraf orcid: 0000-0002-8662-1101 - first_name: Kirill full_name: Koshelev, Kirill last_name: Koshelev - first_name: Yuri S. full_name: Kivshar, Yuri S. last_name: Kivshar - first_name: Xin full_name: Li, Xin last_name: Li - first_name: Trevon full_name: Badloe, Trevon last_name: Badloe - first_name: Lingling full_name: Huang, Lingling last_name: Huang - first_name: Junsuk full_name: Rho, Junsuk last_name: Rho - first_name: Shuming full_name: Wang, Shuming last_name: Wang - first_name: Din Ping full_name: Tsai, Din Ping last_name: Tsai - first_name: A. Yu. full_name: Bykov, A. Yu. last_name: Bykov - first_name: Alexey V full_name: Krasavin, Alexey V last_name: Krasavin - first_name: Anatoly V full_name: Zayats, Anatoly V last_name: Zayats - first_name: Cormac full_name: McDonnell, Cormac last_name: McDonnell - first_name: Tal full_name: Ellenbogen, Tal last_name: Ellenbogen - first_name: Xiangang full_name: Luo, Xiangang last_name: Luo - first_name: Mingbo full_name: Pu, Mingbo last_name: Pu - first_name: Francisco J full_name: Garcia-Vidal, Francisco J last_name: Garcia-Vidal - first_name: Liangliang full_name: Liu, Liangliang last_name: Liu - first_name: Zhuo full_name: Li, Zhuo last_name: Li - first_name: Wenxuan full_name: Tang, Wenxuan last_name: Tang - first_name: Hui Feng full_name: Ma, Hui Feng last_name: Ma - first_name: Jingjing full_name: Zhang, Jingjing last_name: Zhang - first_name: Yu full_name: Luo, Yu last_name: Luo - first_name: Xuanru full_name: Zhang, Xuanru last_name: Zhang - first_name: Hao Chi full_name: Zhang, Hao Chi last_name: Zhang - first_name: Pei Hang full_name: He, Pei Hang last_name: He - first_name: Le Peng full_name: Zhang, Le Peng last_name: Zhang - first_name: Xiang full_name: Wan, Xiang last_name: Wan - first_name: Haotian full_name: Wu, Haotian last_name: Wu - first_name: Shuo full_name: Liu, Shuo last_name: Liu - first_name: Wei Xiang full_name: Jiang, Wei Xiang last_name: Jiang - first_name: Xin Ge full_name: Zhang, Xin Ge last_name: Zhang - first_name: Chengwei full_name: Qiu, Chengwei last_name: Qiu - first_name: Qian full_name: Ma, Qian last_name: Ma - first_name: Che full_name: Liu, Che last_name: Liu - first_name: Long full_name: Li, Long last_name: Li - first_name: Jiaqi full_name: Han, Jiaqi last_name: Han - first_name: Lianlin full_name: Li, Lianlin last_name: Li - first_name: Michele full_name: Cotrufo, Michele last_name: Cotrufo - first_name: Christophe full_name: Caloz, Christophe last_name: Caloz - first_name: Z.-L. full_name: Deck-Léger, Z.-L. last_name: Deck-Léger - first_name: A. full_name: Bahrami, A. last_name: Bahrami - first_name: O. full_name: Céspedes, O. last_name: Céspedes - first_name: Emanuele full_name: Galiffi, Emanuele last_name: Galiffi - first_name: P. A. full_name: Huidobro, P. A. last_name: Huidobro - first_name: Qiang full_name: Cheng, Qiang last_name: Cheng - first_name: Jun Yan full_name: Dai, Jun Yan last_name: Dai - first_name: Jun Cheng full_name: Ke, Jun Cheng last_name: Ke - first_name: Lei full_name: Zhang, Lei last_name: Zhang - first_name: Vincenzo full_name: Galdi, Vincenzo last_name: Galdi - first_name: Marco full_name: Di Renzo, Marco last_name: Di Renzo citation: ama: 'Cui TJ, Zhang S, Alu A, et al. Roadmap on electromagnetic metamaterials and metasurfaces. Journal of Physics: Photonics. Published online 2024. doi:10.1088/2515-7647/ad1a3b' apa: 'Cui, T. J., Zhang, S., Alu, A., Wegener, M., Pendry, J., Luo, J., Lai, Y., Wang, Z., Lin, X., Chen, H., Chen, P., Wu, R.-X., Yin, Y., Zhao, P., Chen, H., Li, Y., Zhou, Z., Engheta, N., Asadchy, V. S., … Di Renzo, M. (2024). Roadmap on electromagnetic metamaterials and metasurfaces. Journal of Physics: Photonics. https://doi.org/10.1088/2515-7647/ad1a3b' bibtex: '@article{Cui_Zhang_Alu_Wegener_Pendry_Luo_Lai_Wang_Lin_Chen_et al._2024, title={Roadmap on electromagnetic metamaterials and metasurfaces}, DOI={10.1088/2515-7647/ad1a3b}, journal={Journal of Physics: Photonics}, publisher={IOP Publishing}, author={Cui, Tie Jun and Zhang, Shuang and Alu, Andrea and Wegener, Martin and Pendry, John and Luo, Jie and Lai, Yun and Wang, Zuojia and Lin, Xiao and Chen, Hongsheng and et al.}, year={2024} }' chicago: 'Cui, Tie Jun, Shuang Zhang, Andrea Alu, Martin Wegener, John Pendry, Jie Luo, Yun Lai, et al. “Roadmap on Electromagnetic Metamaterials and Metasurfaces.” Journal of Physics: Photonics, 2024. https://doi.org/10.1088/2515-7647/ad1a3b.' ieee: 'T. J. Cui et al., “Roadmap on electromagnetic metamaterials and metasurfaces,” Journal of Physics: Photonics, 2024, doi: 10.1088/2515-7647/ad1a3b.' mla: 'Cui, Tie Jun, et al. “Roadmap on Electromagnetic Metamaterials and Metasurfaces.” Journal of Physics: Photonics, IOP Publishing, 2024, doi:10.1088/2515-7647/ad1a3b.' short: 'T.J. Cui, S. Zhang, A. Alu, M. Wegener, J. Pendry, J. Luo, Y. Lai, Z. Wang, X. Lin, H. Chen, P. Chen, R.-X. Wu, Y. Yin, P. Zhao, H. Chen, Y. Li, Z. Zhou, N. Engheta, V.S. Asadchy, C. Simovski, S.A. Tretyakov, B. Yang, S.D. Campbell, Y. Hao, D.H. Werner, S. Sun, L. Zhou, S. Xu, H.-B. Sun, Z. Zhou, Z. Li, G. Zheng, X. Chen, T. Li, S.-N. Zhu, J. Zhou, J. Zhao, Z. Liu, Y. Zhang, Q. Zhang, M. Gu, S. Xiao, Y. Liu, X. Zhang, Y. Tang, G. Li, T. Zentgraf, K. Koshelev, Y.S. Kivshar, X. Li, T. Badloe, L. Huang, J. Rho, S. Wang, D.P. Tsai, A.Yu. Bykov, A.V. Krasavin, A.V. Zayats, C. McDonnell, T. Ellenbogen, X. Luo, M. Pu, F.J. Garcia-Vidal, L. Liu, Z. Li, W. Tang, H.F. Ma, J. Zhang, Y. Luo, X. Zhang, H.C. Zhang, P.H. He, L.P. Zhang, X. Wan, H. Wu, S. Liu, W.X. Jiang, X.G. Zhang, C. Qiu, Q. Ma, C. Liu, L. Li, J. Han, L. Li, M. Cotrufo, C. Caloz, Z.-L. Deck-Léger, A. Bahrami, O. Céspedes, E. Galiffi, P.A. Huidobro, Q. Cheng, J.Y. Dai, J.C. Ke, L. Zhang, V. Galdi, M. Di Renzo, Journal of Physics: Photonics (2024).' date_created: 2024-02-20T06:58:48Z date_updated: 2024-02-20T07:03:00Z department: - _id: '15' - _id: '230' - _id: '289' - _id: '623' doi: 10.1088/2515-7647/ad1a3b keyword: - Electrical and Electronic Engineering - Atomic and Molecular Physics - and Optics - Electronic - Optical and Magnetic Materials language: - iso: eng main_file_link: - open_access: '1' url: https://iopscience.iop.org/article/10.1088/2515-7647/ad1a3b oa: '1' publication: 'Journal of Physics: Photonics' publication_identifier: issn: - 2515-7647 publication_status: published publisher: IOP Publishing status: public title: Roadmap on electromagnetic metamaterials and metasurfaces type: journal_article user_id: '30525' year: '2024' ... --- _id: '52217' abstract: - lang: eng text: AbstractPolycarbonate (PC) is an amorphous polymer that is an extremely robust material with a high tenacity, and thus suitable for a lightweight construction with glass‐like transparency. Due to these advantageous properties, PC is often used in industry for example in medical devices, automotive headlamps, sporting equipment, electronics, and a variety of other products. PC is often subjected to uniaxial and biaxial loading conditions. Therefore, reliable material models have to take into account the various resulting experimental effects. For those reasons, we investigate PC specimens under uniaxial and biaxial loading by using different stretch rates and loading scenarios. In addition to that, we propose methods for optical measurement of local stretches to obtain the approximated local true stress. In future work, the displacement fields and the resulting reaction forces will be used for parameter identification of constitutive equations. author: - first_name: Ayoub full_name: Hamdoun, Ayoub last_name: Hamdoun - first_name: Rolf full_name: Mahnken, Rolf id: '335' last_name: Mahnken citation: ama: Hamdoun A, Mahnken R. Experimental investigations of uniaxial and biaxial cold stretching within PC‐films and bars using optical measurements. PAMM. Published online 2024. doi:10.1002/pamm.202300114 apa: Hamdoun, A., & Mahnken, R. (2024). Experimental investigations of uniaxial and biaxial cold stretching within PC‐films and bars using optical measurements. PAMM. https://doi.org/10.1002/pamm.202300114 bibtex: '@article{Hamdoun_Mahnken_2024, title={Experimental investigations of uniaxial and biaxial cold stretching within PC‐films and bars using optical measurements}, DOI={10.1002/pamm.202300114}, journal={PAMM}, publisher={Wiley}, author={Hamdoun, Ayoub and Mahnken, Rolf}, year={2024} }' chicago: Hamdoun, Ayoub, and Rolf Mahnken. “Experimental Investigations of Uniaxial and Biaxial Cold Stretching within PC‐films and Bars Using Optical Measurements.” PAMM, 2024. https://doi.org/10.1002/pamm.202300114. ieee: 'A. Hamdoun and R. Mahnken, “Experimental investigations of uniaxial and biaxial cold stretching within PC‐films and bars using optical measurements,” PAMM, 2024, doi: 10.1002/pamm.202300114.' mla: Hamdoun, Ayoub, and Rolf Mahnken. “Experimental Investigations of Uniaxial and Biaxial Cold Stretching within PC‐films and Bars Using Optical Measurements.” PAMM, Wiley, 2024, doi:10.1002/pamm.202300114. short: A. Hamdoun, R. Mahnken, PAMM (2024). date_created: 2024-02-29T13:53:13Z date_updated: 2024-02-29T13:58:38Z department: - _id: '9' - _id: '154' - _id: '321' doi: 10.1002/pamm.202300114 keyword: - Electrical and Electronic Engineering - Atomic and Molecular Physics - and Optics language: - iso: eng publication: PAMM publication_identifier: issn: - 1617-7061 - 1617-7061 publication_status: published publisher: Wiley quality_controlled: '1' status: public title: Experimental investigations of uniaxial and biaxial cold stretching within PC‐films and bars using optical measurements type: journal_article user_id: '335' year: '2024' ... --- _id: '52218' article_number: '112642' author: - first_name: Peter full_name: Lenz, Peter last_name: Lenz - first_name: Rolf full_name: Mahnken, Rolf id: '335' last_name: Mahnken citation: ama: Lenz P, Mahnken R. Multiscale simulation of polymer curing of composites combined mean-field homogenisation methods at large strains. International Journal of Solids and Structures. 2024;290. doi:10.1016/j.ijsolstr.2023.112642 apa: Lenz, P., & Mahnken, R. (2024). Multiscale simulation of polymer curing of composites combined mean-field homogenisation methods at large strains. International Journal of Solids and Structures, 290, Article 112642. https://doi.org/10.1016/j.ijsolstr.2023.112642 bibtex: '@article{Lenz_Mahnken_2024, title={Multiscale simulation of polymer curing of composites combined mean-field homogenisation methods at large strains}, volume={290}, DOI={10.1016/j.ijsolstr.2023.112642}, number={112642}, journal={International Journal of Solids and Structures}, publisher={Elsevier BV}, author={Lenz, Peter and Mahnken, Rolf}, year={2024} }' chicago: Lenz, Peter, and Rolf Mahnken. “Multiscale Simulation of Polymer Curing of Composites Combined Mean-Field Homogenisation Methods at Large Strains.” International Journal of Solids and Structures 290 (2024). https://doi.org/10.1016/j.ijsolstr.2023.112642. ieee: 'P. Lenz and R. Mahnken, “Multiscale simulation of polymer curing of composites combined mean-field homogenisation methods at large strains,” International Journal of Solids and Structures, vol. 290, Art. no. 112642, 2024, doi: 10.1016/j.ijsolstr.2023.112642.' mla: Lenz, Peter, and Rolf Mahnken. “Multiscale Simulation of Polymer Curing of Composites Combined Mean-Field Homogenisation Methods at Large Strains.” International Journal of Solids and Structures, vol. 290, 112642, Elsevier BV, 2024, doi:10.1016/j.ijsolstr.2023.112642. short: P. Lenz, R. Mahnken, International Journal of Solids and Structures 290 (2024). date_created: 2024-02-29T13:57:56Z date_updated: 2024-02-29T13:58:14Z department: - _id: '9' - _id: '154' - _id: '321' doi: 10.1016/j.ijsolstr.2023.112642 intvolume: ' 290' keyword: - Applied Mathematics - Mechanical Engineering - Mechanics of Materials - Condensed Matter Physics - General Materials Science - Modeling and Simulation language: - iso: eng publication: International Journal of Solids and Structures publication_identifier: issn: - 0020-7683 publication_status: published publisher: Elsevier BV quality_controlled: '1' status: public title: Multiscale simulation of polymer curing of composites combined mean-field homogenisation methods at large strains type: journal_article user_id: '335' volume: 290 year: '2024' ... --- _id: '50726' abstract: - lang: eng text: Resistance spot‐welded joints containing press‐hardened steels are seen to exhibit a fracture mode called total dome failure, where the weld nugget completely separates from one steel sheet along the weld nugget edge. The effect of weld nugget shape and material property gradients is studied based on damage mechanics modeling and experimental validation to shed light on the underlying influencing factors. For a three‐steel‐sheet spot‐welded joint combining DP600 (1.5 mm)–CR1900T (1.0 mm)–CR1900T (1.0 mm), experiments under shear loading reveal that fracture occurs in the DP600 sheet along the weld nugget edge. In subsequent numerical simulation studies with damage mechanics models whose parameters are independently calibrated for every involved material configuration, three variations of the geometrical joint configuration are considered—an approximation of the real joint, one variation with a steeper weld nugget shape, and one variation with a less pronounced gradient between weld nugget material and heat‐affected zone material properties. The results of the finite‐element simulations show that a shallower weld nugget and a more pronounced material gradient lead to a faster increase of plastic strain at the edge of the weld nugget and promote the occurrence of total dome failure. author: - first_name: Lilia full_name: Schuster, Lilia last_name: Schuster - first_name: Viktoria full_name: Olfert, Viktoria id: '5974' last_name: Olfert - first_name: Oleksii full_name: Sherepenko, Oleksii last_name: Sherepenko - first_name: Clemens full_name: Fehrenbach, Clemens last_name: Fehrenbach - first_name: Shiyuan full_name: Song, Shiyuan last_name: Song - first_name: David full_name: Hein, David id: '7728' last_name: Hein - first_name: Gerson full_name: Meschut, Gerson id: '32056' last_name: Meschut orcid: 0000-0002-2763-1246 - first_name: Elliot full_name: Biro, Elliot last_name: Biro - first_name: Sebastian full_name: Münstermann, Sebastian last_name: Münstermann citation: ama: Schuster L, Olfert V, Sherepenko O, et al. Influences of Weld Nugget Shape and Material Gradient on the Shear Strength of Resistance Spot‐Welded Joints. steel research international. Published online 2024. doi:10.1002/srin.202300530 apa: Schuster, L., Olfert, V., Sherepenko, O., Fehrenbach, C., Song, S., Hein, D., Meschut, G., Biro, E., & Münstermann, S. (2024). Influences of Weld Nugget Shape and Material Gradient on the Shear Strength of Resistance Spot‐Welded Joints. Steel Research International. https://doi.org/10.1002/srin.202300530 bibtex: '@article{Schuster_Olfert_Sherepenko_Fehrenbach_Song_Hein_Meschut_Biro_Münstermann_2024, title={Influences of Weld Nugget Shape and Material Gradient on the Shear Strength of Resistance Spot‐Welded Joints}, DOI={10.1002/srin.202300530}, journal={steel research international}, publisher={Wiley}, author={Schuster, Lilia and Olfert, Viktoria and Sherepenko, Oleksii and Fehrenbach, Clemens and Song, Shiyuan and Hein, David and Meschut, Gerson and Biro, Elliot and Münstermann, Sebastian}, year={2024} }' chicago: Schuster, Lilia, Viktoria Olfert, Oleksii Sherepenko, Clemens Fehrenbach, Shiyuan Song, David Hein, Gerson Meschut, Elliot Biro, and Sebastian Münstermann. “Influences of Weld Nugget Shape and Material Gradient on the Shear Strength of Resistance Spot‐Welded Joints.” Steel Research International, 2024. https://doi.org/10.1002/srin.202300530. ieee: 'L. Schuster et al., “Influences of Weld Nugget Shape and Material Gradient on the Shear Strength of Resistance Spot‐Welded Joints,” steel research international, 2024, doi: 10.1002/srin.202300530.' mla: Schuster, Lilia, et al. “Influences of Weld Nugget Shape and Material Gradient on the Shear Strength of Resistance Spot‐Welded Joints.” Steel Research International, Wiley, 2024, doi:10.1002/srin.202300530. short: L. Schuster, V. Olfert, O. Sherepenko, C. Fehrenbach, S. Song, D. Hein, G. Meschut, E. Biro, S. Münstermann, Steel Research International (2024). date_created: 2024-01-22T09:17:07Z date_updated: 2024-03-18T12:49:31Z department: - _id: '157' doi: 10.1002/srin.202300530 keyword: - Materials Chemistry - Metals and Alloys - Physical and Theoretical Chemistry - Condensed Matter Physics language: - iso: eng publication: steel research international publication_identifier: issn: - 1611-3683 - 1869-344X publication_status: published publisher: Wiley quality_controlled: '1' status: public title: Influences of Weld Nugget Shape and Material Gradient on the Shear Strength of Resistance Spot‐Welded Joints type: journal_article user_id: '5974' year: '2024' ... --- _id: '52738' abstract: - lang: eng text: Through tailoring the geometry and design of biomaterials, additive manufacturing is revolutionizing the production of metallic patient-specific implants, e.g., the Ti-6Al-7Nb alloy. Unfortunately, studies investigating this alloy showed that additively produced samples exhibit anisotropic microstructures. This anisotropy compromises the mechanical properties and complicates the loading state in the implant. Moreover, the minimum requirements as specified per designated standards such as ISO 5832-11 are not met. The remedy to this problem is performing a conventional heat treatment. As this route requires energy, infrastructure, labor, and expertise, which in turn mean time and money, many of the additive manufacturing benefits are negated. Thus, the goal of this work was to achieve better isotropy by applying only adapted additive manufacturing process parameters, specifically focusing on the build orientations. In this work, samples orientated in 90°, 45°, and 0° directions relative to the building platform were manufactured and tested. These tests included mechanical (tensile and fatigue tests) as well as microstructural analyses (SEM and EBSD). Subsequently, the results of these tests such as fractography were correlated with the acquired mechanical properties. These showed that 90°-aligned samples performed best under fatigue load and that all requirements specified by the standard regarding monotonic load were met. article_number: '117' author: - first_name: Dennis full_name: Milaege, Dennis id: '35461' last_name: Milaege - first_name: Niklas full_name: Eschemann, Niklas last_name: Eschemann - first_name: Kay-Peter full_name: Hoyer, Kay-Peter id: '48411' last_name: Hoyer - first_name: Mirko full_name: Schaper, Mirko id: '43720' last_name: Schaper citation: ama: Milaege D, Eschemann N, Hoyer K-P, Schaper M. Anisotropic Mechanical and Microstructural Properties of a Ti-6Al-7Nb Alloy for Biomedical Applications Manufactured via Laser Powder Bed Fusion. Crystals. 2024;14(2). doi:10.3390/cryst14020117 apa: Milaege, D., Eschemann, N., Hoyer, K.-P., & Schaper, M. (2024). Anisotropic Mechanical and Microstructural Properties of a Ti-6Al-7Nb Alloy for Biomedical Applications Manufactured via Laser Powder Bed Fusion. Crystals, 14(2), Article 117. https://doi.org/10.3390/cryst14020117 bibtex: '@article{Milaege_Eschemann_Hoyer_Schaper_2024, title={Anisotropic Mechanical and Microstructural Properties of a Ti-6Al-7Nb Alloy for Biomedical Applications Manufactured via Laser Powder Bed Fusion}, volume={14}, DOI={10.3390/cryst14020117}, number={2117}, journal={Crystals}, publisher={MDPI AG}, author={Milaege, Dennis and Eschemann, Niklas and Hoyer, Kay-Peter and Schaper, Mirko}, year={2024} }' chicago: Milaege, Dennis, Niklas Eschemann, Kay-Peter Hoyer, and Mirko Schaper. “Anisotropic Mechanical and Microstructural Properties of a Ti-6Al-7Nb Alloy for Biomedical Applications Manufactured via Laser Powder Bed Fusion.” Crystals 14, no. 2 (2024). https://doi.org/10.3390/cryst14020117. ieee: 'D. Milaege, N. Eschemann, K.-P. Hoyer, and M. Schaper, “Anisotropic Mechanical and Microstructural Properties of a Ti-6Al-7Nb Alloy for Biomedical Applications Manufactured via Laser Powder Bed Fusion,” Crystals, vol. 14, no. 2, Art. no. 117, 2024, doi: 10.3390/cryst14020117.' mla: Milaege, Dennis, et al. “Anisotropic Mechanical and Microstructural Properties of a Ti-6Al-7Nb Alloy for Biomedical Applications Manufactured via Laser Powder Bed Fusion.” Crystals, vol. 14, no. 2, 117, MDPI AG, 2024, doi:10.3390/cryst14020117. short: D. Milaege, N. Eschemann, K.-P. Hoyer, M. Schaper, Crystals 14 (2024). date_created: 2024-03-22T13:46:37Z date_updated: 2024-03-22T14:22:36Z department: - _id: '158' - _id: '321' doi: 10.3390/cryst14020117 intvolume: ' 14' issue: '2' keyword: - Inorganic Chemistry - Condensed Matter Physics - General Materials Science - General Chemical Engineering language: - iso: eng publication: Crystals publication_identifier: issn: - 2073-4352 publication_status: published publisher: MDPI AG quality_controlled: '1' status: public title: Anisotropic Mechanical and Microstructural Properties of a Ti-6Al-7Nb Alloy for Biomedical Applications Manufactured via Laser Powder Bed Fusion type: journal_article user_id: '35461' volume: 14 year: '2024' ... --- _id: '52372' abstract: - lang: eng text: Due to the hydrolytic instability of LiPF6 in carbonate-based solvents, HF is a typical impurity in Li-ion battery electrolytes. HF significantly influences the performance of Li-ion batteries, for example by impacting the formation of the solid electrolyte interphase at the anode and by affecting transition metal dissolution at the cathode. Additionally, HF complicates studying fundamental interfacial electrochemistry of Li-ion battery electrolytes, such as direct anion reduction, because it is electrocatalytically relatively unstable, resulting in LiF passivation layers. Methods to selectively remove ppm levels of HF from LiPF6-containing carbonate-based electrolytes are limited. We introduce and benchmark a simple yet efficient electrochemical in situ method to selectively remove ppm amounts of HF from LiPF6-containing carbonate-based electrolytes. The basic idea is the application of a suitable potential to a high surface-area metallic electrode upon which only HF reacts (electrocatalytically) while all other electrolyte components are unaffected under the respective conditions. article_type: original author: - first_name: Xiaokun full_name: Ge, Xiaokun last_name: Ge - first_name: Marten full_name: Huck, Marten last_name: Huck - first_name: Andreas full_name: Kuhlmann, Andreas last_name: Kuhlmann - first_name: Michael full_name: Tiemann, Michael id: '23547' last_name: Tiemann orcid: 0000-0003-1711-2722 - first_name: Christian full_name: Weinberger, Christian id: '11848' last_name: Weinberger - first_name: Xiaodan full_name: Xu, Xiaodan last_name: Xu - first_name: Zhenyu full_name: Zhao, Zhenyu last_name: Zhao - first_name: Hans-Georg full_name: Steinrueck, Hans-Georg last_name: Steinrueck citation: ama: Ge X, Huck M, Kuhlmann A, et al. Electrochemical Removal of HF from Carbonate-based LiPF6-containing Li-ion Battery Electrolytes. Journal of The Electrochemical Society. 2024;171:030552. doi:10.1149/1945-7111/ad30d3 apa: Ge, X., Huck, M., Kuhlmann, A., Tiemann, M., Weinberger, C., Xu, X., Zhao, Z., & Steinrueck, H.-G. (2024). Electrochemical Removal of HF from Carbonate-based LiPF6-containing Li-ion Battery Electrolytes. Journal of The Electrochemical Society, 171, 030552. https://doi.org/10.1149/1945-7111/ad30d3 bibtex: '@article{Ge_Huck_Kuhlmann_Tiemann_Weinberger_Xu_Zhao_Steinrueck_2024, title={Electrochemical Removal of HF from Carbonate-based LiPF6-containing Li-ion Battery Electrolytes}, volume={171}, DOI={10.1149/1945-7111/ad30d3}, journal={Journal of The Electrochemical Society}, publisher={The Electrochemical Society}, author={Ge, Xiaokun and Huck, Marten and Kuhlmann, Andreas and Tiemann, Michael and Weinberger, Christian and Xu, Xiaodan and Zhao, Zhenyu and Steinrueck, Hans-Georg}, year={2024}, pages={030552} }' chicago: 'Ge, Xiaokun, Marten Huck, Andreas Kuhlmann, Michael Tiemann, Christian Weinberger, Xiaodan Xu, Zhenyu Zhao, and Hans-Georg Steinrueck. “Electrochemical Removal of HF from Carbonate-Based LiPF6-Containing Li-Ion Battery Electrolytes.” Journal of The Electrochemical Society 171 (2024): 030552. https://doi.org/10.1149/1945-7111/ad30d3.' ieee: 'X. Ge et al., “Electrochemical Removal of HF from Carbonate-based LiPF6-containing Li-ion Battery Electrolytes,” Journal of The Electrochemical Society, vol. 171, p. 030552, 2024, doi: 10.1149/1945-7111/ad30d3.' mla: Ge, Xiaokun, et al. “Electrochemical Removal of HF from Carbonate-Based LiPF6-Containing Li-Ion Battery Electrolytes.” Journal of The Electrochemical Society, vol. 171, The Electrochemical Society, 2024, p. 030552, doi:10.1149/1945-7111/ad30d3. short: X. Ge, M. Huck, A. Kuhlmann, M. Tiemann, C. Weinberger, X. Xu, Z. Zhao, H.-G. Steinrueck, Journal of The Electrochemical Society 171 (2024) 030552. date_created: 2024-03-08T06:27:10Z date_updated: 2024-03-25T17:01:09Z department: - _id: '35' - _id: '2' - _id: '307' doi: 10.1149/1945-7111/ad30d3 intvolume: ' 171' keyword: - Materials Chemistry - Electrochemistry - Surfaces - Coatings and Films - Condensed Matter Physics - Renewable Energy - Sustainability and the Environment - Electronic - Optical and Magnetic Materials language: - iso: eng main_file_link: - open_access: '1' url: https://dx.doi.org/10.1149/1945-7111/ad30d3 oa: '1' page: '030552' publication: Journal of The Electrochemical Society publication_identifier: issn: - 0013-4651 - 1945-7111 publication_status: published publisher: The Electrochemical Society quality_controlled: '1' status: public title: Electrochemical Removal of HF from Carbonate-based LiPF6-containing Li-ion Battery Electrolytes type: journal_article user_id: '23547' volume: 171 year: '2024' ... --- _id: '55159' abstract: - lang: eng text: "We introduce a method based on Gaussian process regression to identify discrete variational principles from observed solutions of a field theory. The method is based on the data-based identification of a discrete Lagrangian density. It is a geometric machine learning technique in the sense that the variational structure of the true field theory is reflected in the data-driven model by design. We provide a rigorous convergence statement of the method. The proof circumvents challenges posed by the ambiguity of discrete Lagrangian densities in the inverse problem of variational calculus.\r\nMoreover, our method can be used to quantify model uncertainty in the equations of motions and any linear observable of the discrete field theory. This is illustrated on the example of the discrete wave equation and Schrödinger equation.\r\nThe article constitutes an extension of our previous article arXiv:2404.19626 for the data-driven identification of (discrete) Lagrangians for variational dynamics from an ode setting to the setting of discrete pdes." author: - first_name: Christian full_name: Offen, Christian id: '85279' last_name: Offen orcid: 0000-0002-5940-8057 citation: ama: Offen C. Machine learning of discrete field theories with guaranteed convergence and uncertainty quantification. apa: Offen, C. (n.d.). Machine learning of discrete field theories with guaranteed convergence and uncertainty quantification. bibtex: '@article{Offen, title={Machine learning of discrete field theories with guaranteed convergence and uncertainty quantification}, author={Offen, Christian} }' chicago: Offen, Christian. “Machine Learning of Discrete Field Theories with Guaranteed Convergence and Uncertainty Quantification,” n.d. ieee: C. Offen, “Machine learning of discrete field theories with guaranteed convergence and uncertainty quantification.” . mla: Offen, Christian. Machine Learning of Discrete Field Theories with Guaranteed Convergence and Uncertainty Quantification. short: C. Offen, (n.d.). date_created: 2024-07-10T13:43:50Z date_updated: 2024-08-12T13:43:32Z ddc: - '510' department: - _id: '636' external_id: arxiv: - '2407.07642' file: - access_level: open_access content_type: application/pdf creator: coffen date_created: 2024-07-10T13:39:32Z date_updated: 2024-07-10T13:39:32Z description: |- We introduce a method based on Gaussian process regression to identify discrete variational principles from observed solutions of a field theory. The method is based on the data-based identification of a discrete Lagrangian density. It is a geometric machine learning technique in the sense that the variational structure of the true field theory is reflected in the data-driven model by design. We provide a rigorous convergence statement of the method. The proof circumvents challenges posed by the ambiguity of discrete Lagrangian densities in the inverse problem of variational calculus. Moreover, our method can be used to quantify model uncertainty in the equations of motions and any linear observable of the discrete field theory. This is illustrated on the example of the discrete wave equation and Schrödinger equation. The article constitutes an extension of our previous article for the data-driven identification of (discrete) Lagrangians for variational dynamics from an ode setting to the setting of discrete pdes. file_id: '55160' file_name: L_Collocation.pdf file_size: 4569314 relation: main_file title: Machine learning of discrete field theories with guaranteed convergence and uncertainty quantification file_date_updated: 2024-07-10T13:39:32Z has_accepted_license: '1' keyword: - System identification - inverse problem of variational calculus - Gaussian process - Lagrangian learning - physics informed machine learning - geometry aware learning language: - iso: eng oa: '1' page: '28' project: - _id: '52' name: 'PC2: Computing Resources Provided by the Paderborn Center for Parallel Computing' publication_status: submitted related_material: link: - description: GitHub relation: software url: https://github.com/Christian-Offen/Lagrangian_GP_PDE status: public title: Machine learning of discrete field theories with guaranteed convergence and uncertainty quantification type: preprint user_id: '85279' year: '2024' ... --- _id: '49652' abstract: - lang: eng text: Broadband coherent anti-Stokes Raman scattering (BCARS) is a powerful spectroscopy method combining high signal intensity with spectral sensitivity, enabling rapid imaging of heterogeneous samples in biomedical research and, more recently, in crystalline materials. However, BCARS encounters spectral distortion due to a setup-dependent non-resonant background (NRB). This study assesses BCARS reproducibility through a round robin experiment using two distinct BCARS setups and crystalline materials with varying structural complexity, including diamond, 6H-SiC, KDP, and KTP. The analysis compares setup-specific NRB correction procedures, detected and NRB-removed spectra, and mode assignment. We determine the influence of BCARS setup parameters like pump wavelength, pulse width, and detection geometry and provide a practical guide for optimizing BCARS setups for solid-state applications. article_number: '112' article_type: original author: - first_name: Franz full_name: Hempel, Franz last_name: Hempel - first_name: Federico full_name: Vernuccio, Federico last_name: Vernuccio - first_name: Lukas full_name: König, Lukas last_name: König - first_name: Robin full_name: Buschbeck, Robin last_name: Buschbeck - first_name: Michael full_name: Rüsing, Michael id: '22501' last_name: Rüsing orcid: 0000-0003-4682-4577 - first_name: Giulio full_name: Cerullo, Giulio last_name: Cerullo - first_name: Dario full_name: Polli, Dario last_name: Polli - first_name: Lukas M. full_name: Eng, Lukas M. last_name: Eng citation: ama: 'Hempel F, Vernuccio F, König L, et al. Comparing transmission- and epi-BCARS: a round robin on solid-state materials. Applied Optics. 2024;63(1). doi:10.1364/ao.505374' apa: 'Hempel, F., Vernuccio, F., König, L., Buschbeck, R., Rüsing, M., Cerullo, G., Polli, D., & Eng, L. M. (2024). Comparing transmission- and epi-BCARS: a round robin on solid-state materials. Applied Optics, 63(1), Article 112. https://doi.org/10.1364/ao.505374' bibtex: '@article{Hempel_Vernuccio_König_Buschbeck_Rüsing_Cerullo_Polli_Eng_2024, title={Comparing transmission- and epi-BCARS: a round robin on solid-state materials}, volume={63}, DOI={10.1364/ao.505374}, number={1112}, journal={Applied Optics}, publisher={Optica Publishing Group}, author={Hempel, Franz and Vernuccio, Federico and König, Lukas and Buschbeck, Robin and Rüsing, Michael and Cerullo, Giulio and Polli, Dario and Eng, Lukas M.}, year={2024} }' chicago: 'Hempel, Franz, Federico Vernuccio, Lukas König, Robin Buschbeck, Michael Rüsing, Giulio Cerullo, Dario Polli, and Lukas M. Eng. “Comparing Transmission- and Epi-BCARS: A Round Robin on Solid-State Materials.” Applied Optics 63, no. 1 (2024). https://doi.org/10.1364/ao.505374.' ieee: 'F. Hempel et al., “Comparing transmission- and epi-BCARS: a round robin on solid-state materials,” Applied Optics, vol. 63, no. 1, Art. no. 112, 2024, doi: 10.1364/ao.505374.' mla: 'Hempel, Franz, et al. “Comparing Transmission- and Epi-BCARS: A Round Robin on Solid-State Materials.” Applied Optics, vol. 63, no. 1, 112, Optica Publishing Group, 2024, doi:10.1364/ao.505374.' short: F. Hempel, F. Vernuccio, L. König, R. Buschbeck, M. Rüsing, G. Cerullo, D. Polli, L.M. Eng, Applied Optics 63 (2024). date_created: 2023-12-15T07:32:38Z date_updated: 2025-04-03T12:36:01Z department: - _id: '15' - _id: '288' - _id: '623' doi: 10.1364/ao.505374 intvolume: ' 63' issue: '1' keyword: - Atomic and Molecular Physics - and Optics - Engineering (miscellaneous) - Electrical and Electronic Engineering language: - iso: eng main_file_link: - open_access: '1' url: https://arxiv.org/pdf/2306.09701.pdf oa: '1' publication: Applied Optics publication_identifier: issn: - 1559-128X - 2155-3165 publication_status: published publisher: Optica Publishing Group quality_controlled: '1' related_material: link: - relation: confirmation url: https://arxiv.org/abs/2306.09701 status: public title: 'Comparing transmission- and epi-BCARS: a round robin on solid-state materials' type: journal_article user_id: '22501' volume: 63 year: '2024' ... --- _id: '52876' article_number: L012043 author: - first_name: Christian full_name: Arends, Christian id: '43994' last_name: Arends - first_name: Lasse Lennart full_name: Wolf, Lasse Lennart id: '45027' last_name: Wolf orcid: 0000-0001-8893-2045 - first_name: Jasmin full_name: Meinecke, Jasmin last_name: Meinecke - first_name: Sonja full_name: Barkhofen, Sonja id: '48188' last_name: Barkhofen - first_name: Tobias full_name: Weich, Tobias id: '49178' last_name: Weich orcid: 0000-0002-9648-6919 - first_name: Tim full_name: Bartley, Tim id: '49683' last_name: Bartley citation: ama: Arends C, Wolf LL, Meinecke J, Barkhofen S, Weich T, Bartley T. Decomposing large unitaries into multimode devices of arbitrary size. Physical Review Research. 2024;6(1). doi:10.1103/physrevresearch.6.l012043 apa: Arends, C., Wolf, L. L., Meinecke, J., Barkhofen, S., Weich, T., & Bartley, T. (2024). Decomposing large unitaries into multimode devices of arbitrary size. Physical Review Research, 6(1), Article L012043. https://doi.org/10.1103/physrevresearch.6.l012043 bibtex: '@article{Arends_Wolf_Meinecke_Barkhofen_Weich_Bartley_2024, title={Decomposing large unitaries into multimode devices of arbitrary size}, volume={6}, DOI={10.1103/physrevresearch.6.l012043}, number={1L012043}, journal={Physical Review Research}, publisher={American Physical Society (APS)}, author={Arends, Christian and Wolf, Lasse Lennart and Meinecke, Jasmin and Barkhofen, Sonja and Weich, Tobias and Bartley, Tim}, year={2024} }' chicago: Arends, Christian, Lasse Lennart Wolf, Jasmin Meinecke, Sonja Barkhofen, Tobias Weich, and Tim Bartley. “Decomposing Large Unitaries into Multimode Devices of Arbitrary Size.” Physical Review Research 6, no. 1 (2024). https://doi.org/10.1103/physrevresearch.6.l012043. ieee: 'C. Arends, L. L. Wolf, J. Meinecke, S. Barkhofen, T. Weich, and T. Bartley, “Decomposing large unitaries into multimode devices of arbitrary size,” Physical Review Research, vol. 6, no. 1, Art. no. L012043, 2024, doi: 10.1103/physrevresearch.6.l012043.' mla: Arends, Christian, et al. “Decomposing Large Unitaries into Multimode Devices of Arbitrary Size.” Physical Review Research, vol. 6, no. 1, L012043, American Physical Society (APS), 2024, doi:10.1103/physrevresearch.6.l012043. short: C. Arends, L.L. Wolf, J. Meinecke, S. Barkhofen, T. Weich, T. Bartley, Physical Review Research 6 (2024). date_created: 2024-03-26T08:52:05Z date_updated: 2025-12-04T13:38:49Z department: - _id: '623' - _id: '15' doi: 10.1103/physrevresearch.6.l012043 intvolume: ' 6' issue: '1' keyword: - General Physics and Astronomy language: - iso: eng publication: Physical Review Research publication_identifier: issn: - 2643-1564 publication_status: published publisher: American Physical Society (APS) status: public title: Decomposing large unitaries into multimode devices of arbitrary size type: journal_article user_id: '48188' volume: 6 year: '2024' ... --- _id: '47992' abstract: - lang: eng text: Ferroelectric domain boundaries are quasi-two-dimensional functional interfaces with high prospects for nanoelectronic applications. Despite their reduced dimensionality, they can exhibit complex non-Ising polarization configurations and unexpected physical properties. Here, the impact of the three-dimensional (3D) curvature on the polarization profile of nominally uncharged 180° domain walls in LiNbO3 is studied using second-harmonic generation microscopy and 3D polarimetry analysis. Correlations between the domain-wall curvature and the variation of its internal polarization unfold in the form of modulations of the Néel-like character, which we attribute to the flexoelectric effect. While the Néel-like character originates mainly from the tilting of the domain wall, the internal polarization adjusts its orientation due to the synergetic upshot of dipolar and monopolar bound charges and their variation with the 3D curvature. Our results show that curved interfaces in solid crystals may offer a rich playground for tailoring nanoscale polar states. article_type: original author: - first_name: Ulises full_name: Acevedo-Salas, Ulises last_name: Acevedo-Salas - first_name: Boris full_name: Croes, Boris last_name: Croes - first_name: Yide full_name: Zhang, Yide last_name: Zhang - first_name: Olivier full_name: Cregut, Olivier last_name: Cregut - first_name: Kokou Dodzi full_name: Dorkenoo, Kokou Dodzi last_name: Dorkenoo - first_name: Benjamin full_name: Kirbus, Benjamin last_name: Kirbus - first_name: Ekta full_name: Singh, Ekta last_name: Singh - first_name: Henrik full_name: Beccard, Henrik last_name: Beccard - first_name: Michael full_name: Rüsing, Michael id: '22501' last_name: Rüsing orcid: 0000-0003-4682-4577 - first_name: Lukas M. full_name: Eng, Lukas M. last_name: Eng - first_name: Riccardo full_name: Hertel, Riccardo last_name: Hertel - first_name: Eugene A. full_name: Eliseev, Eugene A. last_name: Eliseev - first_name: Anna N. full_name: Morozovska, Anna N. last_name: Morozovska - first_name: Salia full_name: Cherifi-Hertel, Salia last_name: Cherifi-Hertel citation: ama: Acevedo-Salas U, Croes B, Zhang Y, et al. Impact of 3D Curvature on the Polarization Orientation in Non-Ising Domain Walls. Nano Letters. 2023;23(3):795-803. doi:10.1021/acs.nanolett.2c03579 apa: Acevedo-Salas, U., Croes, B., Zhang, Y., Cregut, O., Dorkenoo, K. D., Kirbus, B., Singh, E., Beccard, H., Rüsing, M., Eng, L. M., Hertel, R., Eliseev, E. A., Morozovska, A. N., & Cherifi-Hertel, S. (2023). Impact of 3D Curvature on the Polarization Orientation in Non-Ising Domain Walls. Nano Letters, 23(3), 795–803. https://doi.org/10.1021/acs.nanolett.2c03579 bibtex: '@article{Acevedo-Salas_Croes_Zhang_Cregut_Dorkenoo_Kirbus_Singh_Beccard_Rüsing_Eng_et al._2023, title={Impact of 3D Curvature on the Polarization Orientation in Non-Ising Domain Walls}, volume={23}, DOI={10.1021/acs.nanolett.2c03579}, number={3}, journal={Nano Letters}, publisher={American Chemical Society (ACS)}, author={Acevedo-Salas, Ulises and Croes, Boris and Zhang, Yide and Cregut, Olivier and Dorkenoo, Kokou Dodzi and Kirbus, Benjamin and Singh, Ekta and Beccard, Henrik and Rüsing, Michael and Eng, Lukas M. and et al.}, year={2023}, pages={795–803} }' chicago: 'Acevedo-Salas, Ulises, Boris Croes, Yide Zhang, Olivier Cregut, Kokou Dodzi Dorkenoo, Benjamin Kirbus, Ekta Singh, et al. “Impact of 3D Curvature on the Polarization Orientation in Non-Ising Domain Walls.” Nano Letters 23, no. 3 (2023): 795–803. https://doi.org/10.1021/acs.nanolett.2c03579.' ieee: 'U. Acevedo-Salas et al., “Impact of 3D Curvature on the Polarization Orientation in Non-Ising Domain Walls,” Nano Letters, vol. 23, no. 3, pp. 795–803, 2023, doi: 10.1021/acs.nanolett.2c03579.' mla: Acevedo-Salas, Ulises, et al. “Impact of 3D Curvature on the Polarization Orientation in Non-Ising Domain Walls.” Nano Letters, vol. 23, no. 3, American Chemical Society (ACS), 2023, pp. 795–803, doi:10.1021/acs.nanolett.2c03579. short: U. Acevedo-Salas, B. Croes, Y. Zhang, O. Cregut, K.D. Dorkenoo, B. Kirbus, E. Singh, H. Beccard, M. Rüsing, L.M. Eng, R. Hertel, E.A. Eliseev, A.N. Morozovska, S. Cherifi-Hertel, Nano Letters 23 (2023) 795–803. date_created: 2023-10-11T09:06:05Z date_updated: 2023-10-11T09:06:31Z doi: 10.1021/acs.nanolett.2c03579 extern: '1' intvolume: ' 23' issue: '3' keyword: - Mechanical Engineering - Condensed Matter Physics - General Materials Science - General Chemistry - Bioengineering language: - iso: eng page: 795-803 publication: Nano Letters publication_identifier: issn: - 1530-6984 - 1530-6992 publication_status: published publisher: American Chemical Society (ACS) quality_controlled: '1' status: public title: Impact of 3D Curvature on the Polarization Orientation in Non-Ising Domain Walls type: journal_article user_id: '22501' volume: 23 year: '2023' ... --- _id: '47993' abstract: - lang: eng text: Structural strain severely impacts material properties, such as the linear and nonlinear optical response. Moreover, strain plays a key role, e.g., in the physics of ferroelectrics and, in particular, of their domain walls. μ-Raman spectroscopy is a well-suited technique for the investigation of such strain effects as it allows to measure the lattice dynamics locally. However, quantifying and reconstructing strain fields from Raman maps requires knowledge on the strain dependence of phonon frequencies. In this paper, we have analyzed both theoretically and experimentally the phonon frequencies in the widely used ferroelectrics lithium niobate and lithium tantalate as a function of uniaxial strain via density functional theory and μ-Raman spectroscopy. Overall, we find a good agreement between our ab initio models and the experimental data performed with a stress cell. The majority of phonons show an increase in frequency under compressive strain, whereas the opposite is observed for tensile strains. Moreover, for E-type phonons, we observe the lifting of degeneracy already at moderate strain fields (i.e., at ±0.2%) along the x and y directions. This paper, hence, allows for the systematic analysis of three-dimensional strains in modern-type bulk and thin-film devices assembled from lithium niobate and tantalate. article_number: '024420' article_type: original author: - first_name: Ekta full_name: Singh, Ekta last_name: Singh - first_name: Mike N. full_name: Pionteck, Mike N. last_name: Pionteck - first_name: Sven full_name: Reitzig, Sven last_name: Reitzig - first_name: Michael full_name: Lange, Michael last_name: Lange - first_name: Michael full_name: Rüsing, Michael id: '22501' last_name: Rüsing orcid: 0000-0003-4682-4577 - first_name: Lukas M. full_name: Eng, Lukas M. last_name: Eng - first_name: Simone full_name: Sanna, Simone last_name: Sanna citation: ama: Singh E, Pionteck MN, Reitzig S, et al. Vibrational properties of LiNbO3 and LiTaO3 under uniaxial stress. Physical Review Materials. 2023;7(2). doi:10.1103/physrevmaterials.7.024420 apa: Singh, E., Pionteck, M. N., Reitzig, S., Lange, M., Rüsing, M., Eng, L. M., & Sanna, S. (2023). Vibrational properties of LiNbO3 and LiTaO3 under uniaxial stress. Physical Review Materials, 7(2), Article 024420. https://doi.org/10.1103/physrevmaterials.7.024420 bibtex: '@article{Singh_Pionteck_Reitzig_Lange_Rüsing_Eng_Sanna_2023, title={Vibrational properties of LiNbO3 and LiTaO3 under uniaxial stress}, volume={7}, DOI={10.1103/physrevmaterials.7.024420}, number={2024420}, journal={Physical Review Materials}, publisher={American Physical Society (APS)}, author={Singh, Ekta and Pionteck, Mike N. and Reitzig, Sven and Lange, Michael and Rüsing, Michael and Eng, Lukas M. and Sanna, Simone}, year={2023} }' chicago: Singh, Ekta, Mike N. Pionteck, Sven Reitzig, Michael Lange, Michael Rüsing, Lukas M. Eng, and Simone Sanna. “Vibrational Properties of LiNbO3 and LiTaO3 under Uniaxial Stress.” Physical Review Materials 7, no. 2 (2023). https://doi.org/10.1103/physrevmaterials.7.024420. ieee: 'E. Singh et al., “Vibrational properties of LiNbO3 and LiTaO3 under uniaxial stress,” Physical Review Materials, vol. 7, no. 2, Art. no. 024420, 2023, doi: 10.1103/physrevmaterials.7.024420.' mla: Singh, Ekta, et al. “Vibrational Properties of LiNbO3 and LiTaO3 under Uniaxial Stress.” Physical Review Materials, vol. 7, no. 2, 024420, American Physical Society (APS), 2023, doi:10.1103/physrevmaterials.7.024420. short: E. Singh, M.N. Pionteck, S. Reitzig, M. Lange, M. Rüsing, L.M. Eng, S. Sanna, Physical Review Materials 7 (2023). date_created: 2023-10-11T09:06:56Z date_updated: 2023-10-11T09:08:16Z doi: 10.1103/physrevmaterials.7.024420 extern: '1' intvolume: ' 7' issue: '2' keyword: - Physics and Astronomy (miscellaneous) - General Materials Science language: - iso: eng publication: Physical Review Materials publication_identifier: issn: - 2475-9953 publication_status: published publisher: American Physical Society (APS) quality_controlled: '1' status: public title: Vibrational properties of LiNbO3 and LiTaO3 under uniaxial stress type: journal_article user_id: '22501' volume: 7 year: '2023' ... --- _id: '47994' abstract: - lang: eng text: Coherent nonlinear optical μ-spectroscopy is a frequently used tool in modern material science as it is sensitive to many different local observables, which comprise, among others, crystal symmetry and vibrational properties. The richness in information, however, may come with challenges in data interpretation, as one has to disentangle the many different effects like multiple reflections, phase jumps at interfaces, or the influence of the Guoy-phase. In order to facilitate interpretation, the work presented here proposes an easy-to-use semi-analytical modeling Ansatz, which bases upon known analytical solutions using Gaussian beams. Specifically, we apply this Ansatz to compute nonlinear optical responses of (thin film) optical materials. We try to conserve the meaning of intuitive parameters like the Gouy-phase and the nonlinear coherent interaction length. In particular, the concept of coherence length is extended, which is a must when using focal beams. The model is subsequently applied to exemplary cases of second- and third-harmonic generation. We observe a very good agreement with experimental data, and furthermore, despite the constraints and limits of the analytical Ansatz, our model performs similarly well as when using more rigorous simulations. However, it outperforms the latter in terms of computational power, requiring more than three orders less computational time and less performant computer systems. article_number: '123105' article_type: original author: - first_name: Kai J. full_name: Spychala, Kai J. last_name: Spychala - first_name: Zeeshan H. full_name: Amber, Zeeshan H. last_name: Amber - first_name: Lukas M. full_name: Eng, Lukas M. last_name: Eng - first_name: Michael full_name: Rüsing, Michael id: '22501' last_name: Rüsing orcid: 0000-0003-4682-4577 citation: ama: 'Spychala KJ, Amber ZH, Eng LM, Rüsing M. Modeling nonlinear optical interactions of focused beams in bulk crystals and thin films: A phenomenological approach. Journal of Applied Physics. 2023;133(12). doi:10.1063/5.0136252' apa: 'Spychala, K. J., Amber, Z. H., Eng, L. M., & Rüsing, M. (2023). Modeling nonlinear optical interactions of focused beams in bulk crystals and thin films: A phenomenological approach. Journal of Applied Physics, 133(12), Article 123105. https://doi.org/10.1063/5.0136252' bibtex: '@article{Spychala_Amber_Eng_Rüsing_2023, title={Modeling nonlinear optical interactions of focused beams in bulk crystals and thin films: A phenomenological approach}, volume={133}, DOI={10.1063/5.0136252}, number={12123105}, journal={Journal of Applied Physics}, publisher={AIP Publishing}, author={Spychala, Kai J. and Amber, Zeeshan H. and Eng, Lukas M. and Rüsing, Michael}, year={2023} }' chicago: 'Spychala, Kai J., Zeeshan H. Amber, Lukas M. Eng, and Michael Rüsing. “Modeling Nonlinear Optical Interactions of Focused Beams in Bulk Crystals and Thin Films: A Phenomenological Approach.” Journal of Applied Physics 133, no. 12 (2023). https://doi.org/10.1063/5.0136252.' ieee: 'K. J. Spychala, Z. H. Amber, L. M. Eng, and M. Rüsing, “Modeling nonlinear optical interactions of focused beams in bulk crystals and thin films: A phenomenological approach,” Journal of Applied Physics, vol. 133, no. 12, Art. no. 123105, 2023, doi: 10.1063/5.0136252.' mla: 'Spychala, Kai J., et al. “Modeling Nonlinear Optical Interactions of Focused Beams in Bulk Crystals and Thin Films: A Phenomenological Approach.” Journal of Applied Physics, vol. 133, no. 12, 123105, AIP Publishing, 2023, doi:10.1063/5.0136252.' short: K.J. Spychala, Z.H. Amber, L.M. Eng, M. Rüsing, Journal of Applied Physics 133 (2023). date_created: 2023-10-11T09:09:00Z date_updated: 2023-10-11T16:10:54Z doi: 10.1063/5.0136252 extern: '1' intvolume: ' 133' issue: '12' keyword: - General Physics and Astronomy language: - iso: eng main_file_link: - open_access: '1' url: ' https://doi.org/10.1063/5.0136252' oa: '1' publication: Journal of Applied Physics publication_identifier: issn: - 0021-8979 - 1089-7550 publication_status: published publisher: AIP Publishing quality_controlled: '1' status: public title: 'Modeling nonlinear optical interactions of focused beams in bulk crystals and thin films: A phenomenological approach' type: journal_article user_id: '22501' volume: 133 year: '2023' ... --- _id: '46573' abstract: - lang: eng text: 'An ultra-fast change of the absorption onset for zincblende gallium-nitride (zb-GaN) (fundamental bandgap: 3.23 eV) is observed by investigating the imaginary part of the dielectric function using time-dependent femtosecond pump–probe spectroscopic ellipsometry between 2.9 and 3.7 eV. The 266 nm (4.66 eV) pump pulses induce a large electron–hole pair concentration up to 4×1020cm−3, which shift the transition energy between conduction and valence bands due to many-body effects up to ≈500 meV. Here, the absorption onset increases due to band filling while the bandgap renormalization at the same time decreases the bandgap. Additionally, the absorption of the pump-beam creates a free-carrier profile within the 605 nm zb-GaN layer with high free-carrier concentrations at the surface, and low concentrations at the interface to the substrate. This leads to varying optical properties from the sample surface (high transition energy) to substrate (low transition energy), which are taken into account by grading analysis for an accurate description of the experimental data. For this, a model describing the time- and position-dependent free-carrier concentration is formulated by considering the relaxation, recombination, and diffusion of those carriers. We provide a quantitative analysis of optical experimental data (ellipsometric angles Ψ and Δ) as well as a plot for the time-dependent change of the imaginary part of the dielectric function.' author: - first_name: Elias full_name: Baron, Elias last_name: Baron - first_name: Rüdiger full_name: Goldhahn, Rüdiger last_name: Goldhahn - first_name: Shirly full_name: Espinoza, Shirly last_name: Espinoza - first_name: Martin full_name: Zahradník, Martin last_name: Zahradník - first_name: Mateusz full_name: Rebarz, Mateusz last_name: Rebarz - first_name: Jakob full_name: Andreasson, Jakob last_name: Andreasson - first_name: Michael full_name: Deppe, Michael last_name: Deppe - first_name: Donat Josef full_name: As, Donat Josef id: '14' last_name: As orcid: 0000-0003-1121-3565 - first_name: Martin full_name: Feneberg, Martin last_name: Feneberg citation: ama: Baron E, Goldhahn R, Espinoza S, et al. Time-resolved pump–probe spectroscopic ellipsometry of cubic GaN. I. Determination of the dielectric function. Journal of Applied Physics. 2023;134(7). doi:10.1063/5.0153091 apa: Baron, E., Goldhahn, R., Espinoza, S., Zahradník, M., Rebarz, M., Andreasson, J., Deppe, M., As, D. J., & Feneberg, M. (2023). Time-resolved pump–probe spectroscopic ellipsometry of cubic GaN. I. Determination of the dielectric function. Journal of Applied Physics, 134(7). https://doi.org/10.1063/5.0153091 bibtex: '@article{Baron_Goldhahn_Espinoza_Zahradník_Rebarz_Andreasson_Deppe_As_Feneberg_2023, title={Time-resolved pump–probe spectroscopic ellipsometry of cubic GaN. I. Determination of the dielectric function}, volume={134}, DOI={10.1063/5.0153091}, number={7}, journal={Journal of Applied Physics}, publisher={AIP Publishing}, author={Baron, Elias and Goldhahn, Rüdiger and Espinoza, Shirly and Zahradník, Martin and Rebarz, Mateusz and Andreasson, Jakob and Deppe, Michael and As, Donat Josef and Feneberg, Martin}, year={2023} }' chicago: Baron, Elias, Rüdiger Goldhahn, Shirly Espinoza, Martin Zahradník, Mateusz Rebarz, Jakob Andreasson, Michael Deppe, Donat Josef As, and Martin Feneberg. “Time-Resolved Pump–Probe Spectroscopic Ellipsometry of Cubic GaN. I. Determination of the Dielectric Function.” Journal of Applied Physics 134, no. 7 (2023). https://doi.org/10.1063/5.0153091. ieee: 'E. Baron et al., “Time-resolved pump–probe spectroscopic ellipsometry of cubic GaN. I. Determination of the dielectric function,” Journal of Applied Physics, vol. 134, no. 7, 2023, doi: 10.1063/5.0153091.' mla: Baron, Elias, et al. “Time-Resolved Pump–Probe Spectroscopic Ellipsometry of Cubic GaN. I. Determination of the Dielectric Function.” Journal of Applied Physics, vol. 134, no. 7, AIP Publishing, 2023, doi:10.1063/5.0153091. short: E. Baron, R. Goldhahn, S. Espinoza, M. Zahradník, M. Rebarz, J. Andreasson, M. Deppe, D.J. As, M. Feneberg, Journal of Applied Physics 134 (2023). date_created: 2023-08-18T08:17:41Z date_updated: 2023-10-09T09:17:15Z department: - _id: '15' - _id: '230' doi: 10.1063/5.0153091 intvolume: ' 134' issue: '7' keyword: - General Physics and Astronomy language: - iso: eng publication: Journal of Applied Physics publication_identifier: issn: - 0021-8979 - 1089-7550 publication_status: published publisher: AIP Publishing status: public title: Time-resolved pump–probe spectroscopic ellipsometry of cubic GaN. I. Determination of the dielectric function type: journal_article user_id: '14931' volume: 134 year: '2023' ... --- _id: '47997' abstract: - lang: eng text: The crystal family of potassium titanyl phosphate (KTiOPO4) is a promising material group for applications in quantum and nonlinear optics. The fabrication of low-loss optical waveguides, as well as high-grade periodically poled ferroelectric domain structures, requires a profound understanding of the material properties and crystal structure. In this regard, Raman spectroscopy offers the possibility to study and visualize domain structures, strain, defects, and the local stoichiometry, which are all factors impacting device performance. However, the accurate interpretation of Raman spectra and their changes with respect to extrinsic and intrinsic defects requires a thorough assignment of the Raman modes to their respective crystal features, which to date is only partly conducted based on phenomenological modelling. To address this issue, we calculated the phonon spectra of potassium titanyl phosphate and the related compounds rubidium titanyl phosphate (RbTiOPO4) and potassium titanyl arsenate (KTiOAsO4) based on density functional theory and compared them with experimental data. Overall, this allows us to assign various spectral features to eigenmodes of lattice substructures with improved detail compared to previous assignments. Nevertheless, the analysis also shows that not all features of the spectra can unambigiously be explained yet. A possible explanation might be that defects or long range fields not included in the modeling play a crucial rule for the resulting Raman spectrum. In conclusion, this work provides an improved foundation into the vibrational properties in the KTiOPO4 material family. article_number: '1423' author: - first_name: Sergej full_name: Neufeld, Sergej last_name: Neufeld - first_name: Uwe full_name: Gerstmann, Uwe id: '171' last_name: Gerstmann orcid: 0000-0002-4476-223X - 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: Gerhard full_name: Berth, Gerhard id: '53' last_name: Berth - first_name: Christine full_name: Silberhorn, Christine id: '26263' last_name: Silberhorn - first_name: Lukas M. full_name: Eng, Lukas M. last_name: Eng - first_name: Wolf Gero full_name: Schmidt, Wolf Gero id: '468' last_name: Schmidt orcid: 0000-0002-2717-5076 - first_name: Michael full_name: Rüsing, Michael id: '22501' last_name: Rüsing orcid: 0000-0003-4682-4577 citation: ama: Neufeld S, Gerstmann U, Padberg L, et al. Vibrational Properties of the Potassium Titanyl Phosphate Crystal Family. Crystals. 2023;13(10). doi:10.3390/cryst13101423 apa: Neufeld, S., Gerstmann, U., Padberg, L., Eigner, C., Berth, G., Silberhorn, C., Eng, L. M., Schmidt, W. G., & Rüsing, M. (2023). Vibrational Properties of the Potassium Titanyl Phosphate Crystal Family. Crystals, 13(10), Article 1423. https://doi.org/10.3390/cryst13101423 bibtex: '@article{Neufeld_Gerstmann_Padberg_Eigner_Berth_Silberhorn_Eng_Schmidt_Rüsing_2023, title={Vibrational Properties of the Potassium Titanyl Phosphate Crystal Family}, volume={13}, DOI={10.3390/cryst13101423}, number={101423}, journal={Crystals}, publisher={MDPI AG}, author={Neufeld, Sergej and Gerstmann, Uwe and Padberg, Laura and Eigner, Christof and Berth, Gerhard and Silberhorn, Christine and Eng, Lukas M. and Schmidt, Wolf Gero and Rüsing, Michael}, year={2023} }' chicago: Neufeld, Sergej, Uwe Gerstmann, Laura Padberg, Christof Eigner, Gerhard Berth, Christine Silberhorn, Lukas M. Eng, Wolf Gero Schmidt, and Michael Rüsing. “Vibrational Properties of the Potassium Titanyl Phosphate Crystal Family.” Crystals 13, no. 10 (2023). https://doi.org/10.3390/cryst13101423. ieee: 'S. Neufeld et al., “Vibrational Properties of the Potassium Titanyl Phosphate Crystal Family,” Crystals, vol. 13, no. 10, Art. no. 1423, 2023, doi: 10.3390/cryst13101423.' mla: Neufeld, Sergej, et al. “Vibrational Properties of the Potassium Titanyl Phosphate Crystal Family.” Crystals, vol. 13, no. 10, 1423, MDPI AG, 2023, doi:10.3390/cryst13101423. short: S. Neufeld, U. Gerstmann, L. Padberg, C. Eigner, G. Berth, C. Silberhorn, L.M. Eng, W.G. Schmidt, M. Rüsing, Crystals 13 (2023). date_created: 2023-10-11T09:10:53Z date_updated: 2023-10-11T09:15:58Z department: - _id: '169' doi: 10.3390/cryst13101423 funded_apc: '1' intvolume: ' 13' issue: '10' keyword: - Inorganic Chemistry - Condensed Matter Physics - General Materials Science - General Chemical Engineering language: - iso: eng main_file_link: - open_access: '1' url: https://doi.org/10.3390/cryst13101423 oa: '1' project: - _id: '168' grant_number: '231447078' name: 'TRR 142 - B07: TRR 142 - Polaronen-Einfluss auf die optischen Eigenschaften von Lithiumniobat (B07*)' - _id: '55' name: 'TRR 142 - B: TRR 142 - Project Area B' - _id: '266' grant_number: PROFILNRW-2020-067 name: 'PhoQC: PhoQC: Photonisches Quantencomputing' publication: Crystals publication_identifier: issn: - 2073-4352 publication_status: published publisher: MDPI AG quality_controlled: '1' status: public title: Vibrational Properties of the Potassium Titanyl Phosphate Crystal Family type: journal_article user_id: '22501' volume: 13 year: '2023' ... --- _id: '47996' abstract: - lang: eng text: Specific heat capacity measurements by differential scanning calorimetry (DSC) of single crystals of solid solutions of LiNbO3 and LiTaO3 are reported and compared with corresponding ab initio calculations, with the aim to investigate the variation of the ferroelectric Curie temperature as a function of composition. For this purpose, single crystals of these solid solutions were grown with Czochralski pulling along the c-axis. Elemental composition of Nb and Ta was investigated using XRF analysis, and small samples with homogeneous and well known composition were used for the DSC measurements. We observed that the ferroelectric Curie temperature decreases linearly with increasing Ta concentration in the LiNb1−x Tax O3 solid solution crystals. Furthermore, the ferroelectric transition width of a mixed crystal appears to be smaller, as compared to pure LiTaO3. article_type: original author: - first_name: Umar full_name: Bashir, Umar last_name: Bashir - first_name: Klaus full_name: Böttcher, Klaus last_name: Böttcher - first_name: Detlef full_name: Klimm, Detlef last_name: Klimm - first_name: Steffen full_name: Ganschow, Steffen last_name: Ganschow - first_name: Felix full_name: Bernhardt, Felix last_name: Bernhardt - first_name: Simone full_name: Sanna, Simone last_name: Sanna - first_name: Michael full_name: Rüsing, Michael id: '22501' last_name: Rüsing orcid: 0000-0003-4682-4577 - first_name: Lukas M. full_name: Eng, Lukas M. last_name: Eng - first_name: Matthias full_name: Bickermann, Matthias last_name: Bickermann citation: ama: 'Bashir U, Böttcher K, Klimm D, et al. Solid solutions of lithium niobate and lithium tantalate: crystal growth and the ferroelectric transition. Ferroelectrics. 2023;613(1):250-262. doi:10.1080/00150193.2023.2189842' apa: 'Bashir, U., Böttcher, K., Klimm, D., Ganschow, S., Bernhardt, F., Sanna, S., Rüsing, M., Eng, L. M., & Bickermann, M. (2023). Solid solutions of lithium niobate and lithium tantalate: crystal growth and the ferroelectric transition. Ferroelectrics, 613(1), 250–262. https://doi.org/10.1080/00150193.2023.2189842' bibtex: '@article{Bashir_Böttcher_Klimm_Ganschow_Bernhardt_Sanna_Rüsing_Eng_Bickermann_2023, title={Solid solutions of lithium niobate and lithium tantalate: crystal growth and the ferroelectric transition}, volume={613}, DOI={10.1080/00150193.2023.2189842}, number={1}, journal={Ferroelectrics}, publisher={Informa UK Limited}, author={Bashir, Umar and Böttcher, Klaus and Klimm, Detlef and Ganschow, Steffen and Bernhardt, Felix and Sanna, Simone and Rüsing, Michael and Eng, Lukas M. and Bickermann, Matthias}, year={2023}, pages={250–262} }' chicago: 'Bashir, Umar, Klaus Böttcher, Detlef Klimm, Steffen Ganschow, Felix Bernhardt, Simone Sanna, Michael Rüsing, Lukas M. Eng, and Matthias Bickermann. “Solid Solutions of Lithium Niobate and Lithium Tantalate: Crystal Growth and the Ferroelectric Transition.” Ferroelectrics 613, no. 1 (2023): 250–62. https://doi.org/10.1080/00150193.2023.2189842.' ieee: 'U. Bashir et al., “Solid solutions of lithium niobate and lithium tantalate: crystal growth and the ferroelectric transition,” Ferroelectrics, vol. 613, no. 1, pp. 250–262, 2023, doi: 10.1080/00150193.2023.2189842.' mla: 'Bashir, Umar, et al. “Solid Solutions of Lithium Niobate and Lithium Tantalate: Crystal Growth and the Ferroelectric Transition.” Ferroelectrics, vol. 613, no. 1, Informa UK Limited, 2023, pp. 250–62, doi:10.1080/00150193.2023.2189842.' short: U. Bashir, K. Böttcher, D. Klimm, S. Ganschow, F. Bernhardt, S. Sanna, M. Rüsing, L.M. Eng, M. Bickermann, Ferroelectrics 613 (2023) 250–262. date_created: 2023-10-11T09:10:08Z date_updated: 2023-10-11T09:10:36Z doi: 10.1080/00150193.2023.2189842 extern: '1' intvolume: ' 613' issue: '1' keyword: - Condensed Matter Physics - Electronic - Optical and Magnetic Materials language: - iso: eng page: 250-262 publication: Ferroelectrics publication_identifier: issn: - 0015-0193 - 1563-5112 publication_status: published publisher: Informa UK Limited quality_controlled: '1' status: public title: 'Solid solutions of lithium niobate and lithium tantalate: crystal growth and the ferroelectric transition' type: journal_article user_id: '22501' volume: 613 year: '2023' ... --- _id: '48349' abstract: - lang: eng text: We report a titanium indiffused waveguide resonator featuring an integrated electro-optic modulator for cavity length stabilisation that produces close to 5 dB of squeezed light at 1550 nm (2.4 dB directly measured). The resonator is locked on resonance for tens of minutes with 70 mW of SH light incident on the cavity, demonstrating that photorefraction can be mitigated. Squeezed light production concurrent with cavity length stabilisation utilising the integrated EOM is demonstrated. The device demonstrates the suitability of this platform for squeezed light generation in network applications, where stabilisation to the reference field is typically necessary. article_number: '34903' author: - first_name: M. full_name: Stefszky, M. last_name: Stefszky - first_name: F. full_name: vom Bruch, F. last_name: vom Bruch - first_name: M. full_name: Santandrea, M. last_name: Santandrea - first_name: R. full_name: Ricken, R. last_name: Ricken - first_name: V. full_name: Quiring, V. last_name: Quiring - first_name: C. full_name: Eigner, C. last_name: Eigner - first_name: H full_name: Herrmann, H last_name: Herrmann - first_name: C full_name: Silberhorn, C last_name: Silberhorn citation: ama: Stefszky M, vom Bruch F, Santandrea M, et al. Lithium niobate waveguide squeezer with integrated cavity length stabilisation for network applications. Optics Express. 2023;31(21). doi:10.1364/oe.498423 apa: Stefszky, M., vom Bruch, F., Santandrea, M., Ricken, R., Quiring, V., Eigner, C., Herrmann, H., & Silberhorn, C. (2023). Lithium niobate waveguide squeezer with integrated cavity length stabilisation for network applications. Optics Express, 31(21), Article 34903. https://doi.org/10.1364/oe.498423 bibtex: '@article{Stefszky_vom Bruch_Santandrea_Ricken_Quiring_Eigner_Herrmann_Silberhorn_2023, title={Lithium niobate waveguide squeezer with integrated cavity length stabilisation for network applications}, volume={31}, DOI={10.1364/oe.498423}, number={2134903}, journal={Optics Express}, publisher={Optica Publishing Group}, author={Stefszky, M. and vom Bruch, F. and Santandrea, M. and Ricken, R. and Quiring, V. and Eigner, C. and Herrmann, H and Silberhorn, C}, year={2023} }' chicago: Stefszky, M., F. vom Bruch, M. Santandrea, R. Ricken, V. Quiring, C. Eigner, H Herrmann, and C Silberhorn. “Lithium Niobate Waveguide Squeezer with Integrated Cavity Length Stabilisation for Network Applications.” Optics Express 31, no. 21 (2023). https://doi.org/10.1364/oe.498423. ieee: 'M. Stefszky et al., “Lithium niobate waveguide squeezer with integrated cavity length stabilisation for network applications,” Optics Express, vol. 31, no. 21, Art. no. 34903, 2023, doi: 10.1364/oe.498423.' mla: Stefszky, M., et al. “Lithium Niobate Waveguide Squeezer with Integrated Cavity Length Stabilisation for Network Applications.” Optics Express, vol. 31, no. 21, 34903, Optica Publishing Group, 2023, doi:10.1364/oe.498423. short: M. Stefszky, F. vom Bruch, M. Santandrea, R. Ricken, V. Quiring, C. Eigner, H. Herrmann, C. Silberhorn, Optics Express 31 (2023). date_created: 2023-10-19T14:22:59Z date_updated: 2023-11-02T09:26:42Z department: - _id: '288' - _id: '623' doi: 10.1364/oe.498423 intvolume: ' 31' issue: '21' keyword: - Atomic and Molecular Physics - and Optics language: - iso: eng publication: Optics Express publication_identifier: issn: - 1094-4087 publication_status: published publisher: Optica Publishing Group status: public title: Lithium niobate waveguide squeezer with integrated cavity length stabilisation for network applications type: journal_article user_id: '42777' volume: 31 year: '2023' ...