@inproceedings{62752,
  abstract     = {{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       = {{Vogelsang, Christoph and Grotegut, Lea and Wotschel, Philipp and Janzen, Thomas}},
  keywords     = {{teacher education, physics, assessment, pre-service teachers}},
  location     = {{Copenhagen}},
  title        = {{{Prospective Physics Teachers'  Perceptions of an Objective Structured  Teaching Examination (OSTE)}}},
  year         = {{2025}},
}

@article{51156,
  abstract     = {{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.}},
  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.}},
  issn         = {{2331-7019}},
  journal      = {{Physical Review Applied}},
  keywords     = {{General Physics and Astronomy}},
  number       = {{2}},
  publisher    = {{American Physical Society (APS)}},
  title        = {{{Equivalent-circuit model that quantitatively describes domain-wall conductivity in ferroelectric lithium }}},
  doi          = {{10.1103/physrevapplied.21.024007}},
  volume       = {{21}},
  year         = {{2024}},
}

@article{51221,
  abstract     = {{<jats:p>Charge transfer mechanism in the deprotonation-induced n-type doping of PCBM.</jats:p>}},
  author       = {{Dong, Chuan-Ding and Bauch, Fabian and Hu, Yuanyuan and Schumacher, Stefan}},
  issn         = {{1463-9076}},
  journal      = {{Physical Chemistry Chemical Physics}},
  keywords     = {{Physical and Theoretical Chemistry, General Physics and Astronomy}},
  number       = {{5}},
  pages        = {{4194--4199}},
  publisher    = {{Royal Society of Chemistry (RSC)}},
  title        = {{{Charge transfer in superbase n-type doping of PCBM induced by deprotonation}}},
  doi          = {{10.1039/d3cp05105f}},
  volume       = {{26}},
  year         = {{2024}},
}

@article{51339,
  author       = {{Babai-Hemati, Jonas and vom Bruch, Felix and Herrmann, Harald and Silberhorn, Christine}},
  issn         = {{1094-4087}},
  journal      = {{Optics Express}},
  keywords     = {{Atomic and Molecular Physics, and Optics}},
  publisher    = {{Optica Publishing Group}},
  title        = {{{Tailored second harmonic generation inTi-diffused PPLN waveguides usingmicro-heaters}}},
  doi          = {{10.1364/oe.510319}},
  year         = {{2024}},
}

@article{51519,
  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 Chen, Ping and Wu, Rui-Xin and Yin, Yuhang and Zhao, Pengfei and Chen, Huanyang and Li, Yue and Zhou, Ziheng and Engheta, Nader and Asadchy, V. S. and Simovski, Constantin and Tretyakov, Sergei A and Yang, Biao and Campbell, Sawyer D. and Hao, Yang and Werner, Douglas H and Sun, Shulin and Zhou, Lei and Xu, Su and Sun, Hong-Bo and Zhou, Zhou and Li, Zile and Zheng, Guoxing and Chen, Xianzhong and Li, Tao and Zhu, Shi-Ning and Zhou, Junxiao and Zhao, Junxiang and Liu, Zhaowei and Zhang, Yuchao and Zhang, Qiming and Gu, Min and Xiao, Shumin and Liu, Yongmin and Zhang, Xiaoyu and Tang, Yutao and Li, Guixin and Zentgraf, Thomas and Koshelev, Kirill and Kivshar, Yuri S. and Li, Xin and Badloe, Trevon and Huang, Lingling and Rho, Junsuk and Wang, Shuming and Tsai, Din Ping and Bykov, A. Yu. and Krasavin, Alexey V and Zayats, Anatoly V and McDonnell, Cormac and Ellenbogen, Tal and Luo, Xiangang and Pu, Mingbo and Garcia-Vidal, Francisco J and Liu, Liangliang and Li, Zhuo and Tang, Wenxuan and Ma, Hui Feng and Zhang, Jingjing and Luo, Yu and Zhang, Xuanru and Zhang, Hao Chi and He, Pei Hang and Zhang, Le Peng and Wan, Xiang and Wu, Haotian and Liu, Shuo and Jiang, Wei Xiang and Zhang, Xin Ge and Qiu, Chengwei and Ma, Qian and Liu, Che and Li, Long and Han, Jiaqi and Li, Lianlin and Cotrufo, Michele and Caloz, Christophe and Deck-Léger, Z.-L. and Bahrami, A. and Céspedes, O. and Galiffi, Emanuele and Huidobro, P. A. and Cheng, Qiang and Dai, Jun Yan and Ke, Jun Cheng and Zhang, Lei and Galdi, Vincenzo and Di Renzo, Marco}},
  issn         = {{2515-7647}},
  journal      = {{Journal of Physics: Photonics}},
  keywords     = {{Electrical and Electronic Engineering, Atomic and Molecular Physics, and Optics, Electronic, Optical and Magnetic Materials}},
  publisher    = {{IOP Publishing}},
  title        = {{{Roadmap on electromagnetic metamaterials and metasurfaces}}},
  doi          = {{10.1088/2515-7647/ad1a3b}},
  year         = {{2024}},
}

@article{52217,
  abstract     = {{<jats:title>Abstract</jats:title><jats:p>Polycarbonate (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.</jats:p>}},
  author       = {{Hamdoun, Ayoub and Mahnken, Rolf}},
  issn         = {{1617-7061}},
  journal      = {{PAMM}},
  keywords     = {{Electrical and Electronic Engineering, Atomic and Molecular Physics, and Optics}},
  publisher    = {{Wiley}},
  title        = {{{Experimental investigations of uniaxial and biaxial cold stretching within PC‐films and bars using optical measurements}}},
  doi          = {{10.1002/pamm.202300114}},
  year         = {{2024}},
}

@article{52218,
  author       = {{Lenz, Peter and Mahnken, Rolf}},
  issn         = {{0020-7683}},
  journal      = {{International Journal of Solids and Structures}},
  keywords     = {{Applied Mathematics, Mechanical Engineering, Mechanics of Materials, Condensed Matter Physics, General Materials Science, Modeling and Simulation}},
  publisher    = {{Elsevier BV}},
  title        = {{{Multiscale simulation of polymer curing of composites combined mean-field homogenisation methods at large strains}}},
  doi          = {{10.1016/j.ijsolstr.2023.112642}},
  volume       = {{290}},
  year         = {{2024}},
}

@article{50726,
  abstract     = {{<jats:p>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.</jats:p>}},
  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}},
  issn         = {{1611-3683}},
  journal      = {{steel research international}},
  keywords     = {{Materials Chemistry, Metals and Alloys, Physical and Theoretical Chemistry, Condensed Matter Physics}},
  publisher    = {{Wiley}},
  title        = {{{Influences of Weld Nugget Shape and Material Gradient on the Shear Strength of Resistance Spot‐Welded Joints}}},
  doi          = {{10.1002/srin.202300530}},
  year         = {{2024}},
}

@article{52738,
  abstract     = {{<jats:p>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.</jats:p>}},
  author       = {{Milaege, Dennis and Eschemann, Niklas and Hoyer, Kay-Peter and Schaper, Mirko}},
  issn         = {{2073-4352}},
  journal      = {{Crystals}},
  keywords     = {{Inorganic Chemistry, Condensed Matter Physics, General Materials Science, General Chemical Engineering}},
  number       = {{2}},
  publisher    = {{MDPI AG}},
  title        = {{{Anisotropic Mechanical and Microstructural Properties of a Ti-6Al-7Nb Alloy for Biomedical Applications Manufactured via Laser Powder Bed Fusion}}},
  doi          = {{10.3390/cryst14020117}},
  volume       = {{14}},
  year         = {{2024}},
}

@article{52372,
  abstract     = {{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.}},
  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}},
  issn         = {{0013-4651}},
  journal      = {{Journal of The Electrochemical Society}},
  keywords     = {{Materials Chemistry, Electrochemistry, Surfaces, Coatings and Films, Condensed Matter Physics, Renewable Energy, Sustainability and the Environment, Electronic, Optical and Magnetic Materials}},
  pages        = {{030552}},
  publisher    = {{The Electrochemical Society}},
  title        = {{{Electrochemical Removal of HF from Carbonate-based LiPF6-containing Li-ion Battery Electrolytes}}},
  doi          = {{10.1149/1945-7111/ad30d3}},
  volume       = {{171}},
  year         = {{2024}},
}

@unpublished{55159,
  abstract     = {{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  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       = {{Offen, Christian}},
  keywords     = {{System identification, inverse problem of variational calculus, Gaussian process, Lagrangian learning, physics informed machine learning, geometry aware learning}},
  pages        = {{28}},
  title        = {{{Machine learning of discrete field theories with guaranteed convergence and uncertainty quantification}}},
  year         = {{2024}},
}

@article{49652,
  abstract     = {{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.}},
  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.}},
  issn         = {{1559-128X}},
  journal      = {{Applied Optics}},
  keywords     = {{Atomic and Molecular Physics, and Optics, Engineering (miscellaneous), Electrical and Electronic Engineering}},
  number       = {{1}},
  publisher    = {{Optica Publishing Group}},
  title        = {{{Comparing transmission- and epi-BCARS: a round robin on solid-state materials}}},
  doi          = {{10.1364/ao.505374}},
  volume       = {{63}},
  year         = {{2024}},
}

@article{52876,
  author       = {{Arends, Christian and Wolf, Lasse Lennart and Meinecke, Jasmin and Barkhofen, Sonja and Weich, Tobias and Bartley, Tim}},
  issn         = {{2643-1564}},
  journal      = {{Physical Review Research}},
  keywords     = {{General Physics and Astronomy}},
  number       = {{1}},
  publisher    = {{American Physical Society (APS)}},
  title        = {{{Decomposing large unitaries into multimode devices of arbitrary size}}},
  doi          = {{10.1103/physrevresearch.6.l012043}},
  volume       = {{6}},
  year         = {{2024}},
}

@article{47992,
  abstract     = {{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.}},
  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 Hertel, Riccardo and Eliseev, Eugene A. and Morozovska, Anna N. and Cherifi-Hertel, Salia}},
  issn         = {{1530-6984}},
  journal      = {{Nano Letters}},
  keywords     = {{Mechanical Engineering, Condensed Matter Physics, General Materials Science, General Chemistry, Bioengineering}},
  number       = {{3}},
  pages        = {{795--803}},
  publisher    = {{American Chemical Society (ACS)}},
  title        = {{{Impact of 3D Curvature on the Polarization Orientation in Non-Ising Domain Walls}}},
  doi          = {{10.1021/acs.nanolett.2c03579}},
  volume       = {{23}},
  year         = {{2023}},
}

@article{47993,
  abstract     = {{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.}},
  author       = {{Singh, Ekta and Pionteck, Mike N. and Reitzig, Sven and Lange, Michael and Rüsing, Michael and Eng, Lukas M. and Sanna, Simone}},
  issn         = {{2475-9953}},
  journal      = {{Physical Review Materials}},
  keywords     = {{Physics and Astronomy (miscellaneous), General Materials Science}},
  number       = {{2}},
  publisher    = {{American Physical Society (APS)}},
  title        = {{{Vibrational properties of LiNbO3 and LiTaO3 under uniaxial stress}}},
  doi          = {{10.1103/physrevmaterials.7.024420}},
  volume       = {{7}},
  year         = {{2023}},
}

@article{47994,
  abstract     = {{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.}},
  author       = {{Spychala, Kai J. and Amber, Zeeshan H. and Eng, Lukas M. and Rüsing, Michael}},
  issn         = {{0021-8979}},
  journal      = {{Journal of Applied Physics}},
  keywords     = {{General Physics and Astronomy}},
  number       = {{12}},
  publisher    = {{AIP Publishing}},
  title        = {{{Modeling nonlinear optical interactions of focused beams in bulk crystals and thin films: A phenomenological approach}}},
  doi          = {{10.1063/5.0136252}},
  volume       = {{133}},
  year         = {{2023}},
}

@article{46573,
  abstract     = {{<jats:p>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.</jats:p>}},
  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}},
  issn         = {{0021-8979}},
  journal      = {{Journal of Applied Physics}},
  keywords     = {{General Physics and Astronomy}},
  number       = {{7}},
  publisher    = {{AIP Publishing}},
  title        = {{{Time-resolved pump–probe spectroscopic ellipsometry of cubic GaN. I. Determination of the dielectric function}}},
  doi          = {{10.1063/5.0153091}},
  volume       = {{134}},
  year         = {{2023}},
}

@article{47997,
  abstract     = {{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.}},
  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}},
  issn         = {{2073-4352}},
  journal      = {{Crystals}},
  keywords     = {{Inorganic Chemistry, Condensed Matter Physics, General Materials Science, General Chemical Engineering}},
  number       = {{10}},
  publisher    = {{MDPI AG}},
  title        = {{{Vibrational Properties of the Potassium Titanyl Phosphate Crystal Family}}},
  doi          = {{10.3390/cryst13101423}},
  volume       = {{13}},
  year         = {{2023}},
}

@article{47996,
  abstract     = {{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.}},
  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}},
  issn         = {{0015-0193}},
  journal      = {{Ferroelectrics}},
  keywords     = {{Condensed Matter Physics, Electronic, Optical and Magnetic Materials}},
  number       = {{1}},
  pages        = {{250--262}},
  publisher    = {{Informa UK Limited}},
  title        = {{{Solid solutions of lithium niobate and lithium tantalate: crystal growth and the ferroelectric transition}}},
  doi          = {{10.1080/00150193.2023.2189842}},
  volume       = {{613}},
  year         = {{2023}},
}

@article{48349,
  abstract     = {{<jats:p>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.</jats:p>}},
  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}},
  issn         = {{1094-4087}},
  journal      = {{Optics Express}},
  keywords     = {{Atomic and Molecular Physics, and Optics}},
  number       = {{21}},
  publisher    = {{Optica Publishing Group}},
  title        = {{{Lithium niobate waveguide squeezer with integrated cavity length stabilisation for network applications}}},
  doi          = {{10.1364/oe.498423}},
  volume       = {{31}},
  year         = {{2023}},
}