@article{33965,
  author       = {{Bocchini, Adriana and Gerstmann, Uwe and Bartley, Tim and Steinrück, Hans-Georg and Henkel, Gerald and Schmidt, Wolf Gero}},
  journal      = {{Phys. Rev. Materials}},
  pages        = {{105401}},
  publisher    = {{American Physical Society}},
  title        = {{{Electrochemical performance of KTiOAsO_4 (KTA) in potassium-ion batteries from density-functional theory}}},
  doi          = {{10.1103/PhysRevMaterials.6.105401}},
  volume       = {{6}},
  year         = {{2022}},
}

@article{31254,
  author       = {{Bocchini, Adriana and Gerstmann, Uwe and Schmidt, Wolf Gero}},
  journal      = {{Phys. Rev. B}},
  pages        = {{205118}},
  publisher    = {{American Physical Society}},
  title        = {{{Oxygen vacancies in KTiOPO_4: Optical absorption from hybrid DFT}}},
  doi          = {{10.1103/PhysRevB.105.205118}},
  volume       = {{105}},
  year         = {{2022}},
}

@article{44088,
  abstract     = {{Hole polarons and defect-bound exciton polarons in lithium niobate are investigated by means of density-functional theory, where the localization of the holes is achieved by applying the +U approach to the oxygen 2p orbitals. We find three principal configurations of hole polarons: (i) self-trapped holes localized at displaced regular oxygen atoms and (ii) two other configurations bound to a lithium vacancy either at a threefold coordinated oxygen atom above or at a two-fold coordinated oxygen atom below the defect. The latter is the most stable and is in excellent quantitative agreement with measured g factors from electron paramagnetic resonance. Due to the absence of mid-gap states, none of these hole polarons can explain the broad optical absorption centered between 2.5 and 2.8 eV that is observed in transient absorption spectroscopy, but such states appear if a free electron polaron is trapped at the same lithium vacancy as the bound hole polaron, resulting in an exciton polaron. The dielectric function calculated by solving the Bethe–Salpeter equation indeed yields an optical peak at 2.6 eV in agreement with the two-photon experiments. The coexistence of hole and exciton polarons, which are simultaneously created in optical excitations, thus satisfactorily explains the reported experimental data.}},
  author       = {{Schmidt, Falko and Kozub, Agnieszka L. and Gerstmann, Uwe and Schmidt, Wolf Gero and Schindlmayr, Arno}},
  issn         = {{2073-4352}},
  journal      = {{Crystals}},
  number       = {{11}},
  publisher    = {{MDPI AG}},
  title        = {{{A density-functional theory study of hole and defect-bound exciton polarons in lithium niobate}}},
  doi          = {{10.3390/cryst12111586}},
  volume       = {{12}},
  year         = {{2022}},
}

@article{34094,
  author       = {{Gao, Ying and Li, Yao and Ma, Xuekai and Gao, Meini and Dai, Haitao and Schumacher, Stefan and Gao, Tingge}},
  issn         = {{0003-6951}},
  journal      = {{Applied Physics Letters}},
  keywords     = {{Physics and Astronomy (miscellaneous)}},
  number       = {{20}},
  publisher    = {{AIP Publishing}},
  title        = {{{Tilting nondispersive bands in an empty microcavity}}},
  doi          = {{10.1063/5.0093908}},
  volume       = {{121}},
  year         = {{2022}},
}

@article{31937,
  author       = {{Li, Yao and Ma, Xuekai and Hatzopoulos, Zaharias and Savvidis, Pavlos G. and Schumacher, Stefan and Gao, Tingge}},
  issn         = {{2330-4022}},
  journal      = {{ACS Photonics}},
  number       = {{6}},
  pages        = {{2079--2086}},
  publisher    = {{American Chemical Society (ACS)}},
  title        = {{{Switching Off a Microcavity Polariton Condensate near the Exceptional Point}}},
  doi          = {{10.1021/acsphotonics.2c00288}},
  volume       = {{9}},
  year         = {{2022}},
}

@article{37713,
  author       = {{Murzakhanov, Fadis F. and Mamin, Georgy Vladimirovich and Orlinskii, Sergei Borisovich and Gerstmann, Uwe and Schmidt, Wolf Gero and Biktagirov, Timur and Aharonovich, Igor and Gottscholl, Andreas and Sperlich, Andreas and Dyakonov, Vladimir and Soltamov, Victor A.}},
  issn         = {{1530-6984}},
  journal      = {{Nano Letters}},
  keywords     = {{Mechanical Engineering, Condensed Matter Physics, General Materials Science, General Chemistry, Bioengineering}},
  number       = {{7}},
  pages        = {{2718--2724}},
  publisher    = {{American Chemical Society (ACS)}},
  title        = {{{Electron–Nuclear Coherent Coupling and Nuclear Spin Readout through Optically Polarized V<sub>B</sub><sup>–</sup> Spin States in hBN}}},
  doi          = {{10.1021/acs.nanolett.1c04610}},
  volume       = {{22}},
  year         = {{2022}},
}

@article{33080,
  author       = {{Long, Teng and Ma, Xuekai and Ren, Jiahuan and Li, Feng and Liao, Qing and Schumacher, Stefan and Malpuech, Guillaume and Solnyshkov, Dmitry and Fu, Hongbing}},
  issn         = {{2198-3844}},
  journal      = {{Advanced Science}},
  keywords     = {{General Physics and Astronomy, General Engineering, Biochemistry, Genetics and Molecular Biology (miscellaneous), General Materials Science, General Chemical Engineering, Medicine (miscellaneous)}},
  number       = {{29}},
  publisher    = {{Wiley}},
  title        = {{{Helical Polariton Lasing from Topological Valleys in an Organic Crystalline Microcavity}}},
  doi          = {{10.1002/advs.202203588}},
  volume       = {{9}},
  year         = {{2022}},
}

@article{32310,
  author       = {{Li, Yao and Ma, Xuekai and Zhai, Xiaokun and Gao, Meini and Dai, Haitao and Schumacher, Stefan and Gao, Tingge}},
  issn         = {{2041-1723}},
  journal      = {{Nature Communications}},
  keywords     = {{General Physics and Astronomy, General Biochemistry, Genetics and Molecular Biology, General Chemistry, Multidisciplinary}},
  number       = {{1}},
  publisher    = {{Springer Science and Business Media LLC}},
  title        = {{{Manipulating polariton condensates by Rashba-Dresselhaus coupling at room temperature}}},
  doi          = {{10.1038/s41467-022-31529-4}},
  volume       = {{13}},
  year         = {{2022}},
}

@article{32148,
  author       = {{Gao, Xinghui and Hu, Wei and Schumacher, Stefan and Ma, Xuekai}},
  issn         = {{0146-9592}},
  journal      = {{Optics Letters}},
  keywords     = {{Atomic and Molecular Physics, and Optics}},
  number       = {{13}},
  pages        = {{3235--3238}},
  publisher    = {{Optica Publishing Group}},
  title        = {{{Unidirectional vortex waveguides and multistable vortex pairs in polariton condensates}}},
  doi          = {{10.1364/ol.457724}},
  volume       = {{47}},
  year         = {{2022}},
}

@inbook{30288,
  abstract     = {{Lithium niobate (LiNbO3), a material frequently used in optical applications, hosts different kinds of polarons that significantly affect many of its physical properties. In this study, a variety of electron polarons, namely free, bound, and bipolarons, are analyzed using first-principles calculations. We perform a full structural optimization based on density-functional theory for selected intrinsic defects with special attention to the role of symmetry-breaking distortions that lower the total energy. The cations hosting the various polarons relax to a different degree, with a larger relaxation corresponding to a larger gap between the defect level and the conduction-band edge. The projected density of states reveals that the polaron states are formerly empty Nb 4d states lowered into the band gap. Optical absorption spectra are derived within the independent-particle approximation, corrected by the GW approximation that yields a wider band gap and by including excitonic effects within the Bethe-Salpeter equation. Comparing the calculated spectra with the density of states, we find that the defect peak observed in the optical absorption stems from transitions between the defect level and a continuum of empty Nb 4d states. Signatures of polarons are further analyzed in the reflectivity and other experimentally measurable optical coefficients.}},
  author       = {{Schmidt, Falko and Kozub, Agnieszka L. and Gerstmann, Uwe and Schmidt, Wolf Gero and Schindlmayr, Arno}},
  booktitle    = {{New Trends in Lithium Niobate: From Bulk to Nanocrystals}},
  editor       = {{Corradi, Gábor and Kovács, László}},
  isbn         = {{978-3-0365-3340-7}},
  pages        = {{231--248}},
  publisher    = {{MDPI}},
  title        = {{{Electron polarons in lithium niobate: Charge localization, lattice deformation, and optical response}}},
  doi          = {{10.3390/books978-3-0365-3339-1}},
  year         = {{2022}},
}

@article{40371,
  abstract     = {{<jats:p>Multimode integrated interferometers have great potential for both spectral engineering and metrological applications. However, the material dispersion of integrated platforms constitutes an obstacle that limits the performance and precision of such interferometers. At the same time, two-colour nonlinear interferometers present an important tool for metrological applications, when measurements in a certain frequency range are difficult. In this manuscript, we theoretically developed and investigated an integrated multimode two-colour SU(1,1) interferometer operating in a supersensitive mode. By ensuring the proper design of the integrated platform, we suppressed the dispersion, thereby significantly increasing the visibility of the interference pattern. The use of a continuous wave pump laser provided the symmetry between the spectral shapes of the signal and idler photons concerning half the pump frequency, despite different photon colours. We demonstrate that such an interferometer overcomes the classical phase sensitivity limit for wide parametric gain ranges, when up to 3×104 photons are generated.</jats:p>}},
  author       = {{Ferreri, Alessandro and Sharapova, Polina R.}},
  issn         = {{2073-8994}},
  journal      = {{Symmetry}},
  keywords     = {{Physics and Astronomy (miscellaneous), General Mathematics, Chemistry (miscellaneous), Computer Science (miscellaneous)}},
  number       = {{3}},
  publisher    = {{MDPI AG}},
  title        = {{{Two-Colour Spectrally Multimode Integrated SU(1,1) Interferometer}}},
  doi          = {{10.3390/sym14030552}},
  volume       = {{14}},
  year         = {{2022}},
}

@article{30210,
  abstract     = {{Lithium niobate on insulator (LNOI) has a great potential for photonic integrated circuits, providing substantial versatility in design of various integrated components. To properly use these components in the implementation of different quantum protocols, photons with different properties are required. In this paper, we theoretically demonstrate a flexible source of correlated photons built on the LNOI waveguide of a special geometry. This source is based on the parametric down-conversion (PDC) process, in which the signal and idler photons are generated at the telecom wavelength and have different spatial profiles and polarizations, but the same group velocities. Distinguishability in polarizations and spatial profiles facilitates the routing and manipulating individual photons, while the equality of their group velocities leads to the absence of temporal walk-off between photons. We show how the spectral properties of the generated photons and the number of their frequency modes can be controlled depending on the pump characteristics and the waveguide length. Finally, we discuss special regimes, in which narrowband light with strong frequency correlations and polarization-entangled Bell states are generated at the telecom wavelength.}},
  author       = {{Ebers, Lena and Ferreri, Alessandro and Hammer, Manfred and Albert, Maximilian and Meier, Cedrik and Förstner, Jens and Sharapova, Polina R.}},
  issn         = {{2515-7647}},
  journal      = {{Journal of Physics: Photonics}},
  keywords     = {{tet_topic_waveguide}},
  pages        = {{025001}},
  publisher    = {{IOP Publishing}},
  title        = {{{Flexible source of correlated photons based on LNOI rib waveguides}}},
  doi          = {{10.1088/2515-7647/ac5a5b}},
  volume       = {{4}},
  year         = {{2022}},
}

@article{30921,
  abstract     = {{Quantum walks function as essential means to implement quantum simulators, allowing one to study complex and often directly inaccessible quantum processes in controllable systems. In this contribution, the notion of a driven Gaussian quantum walk is introduced. In contrast to typically considered quantum walks in optical settings, we describe the operation of the walk in terms of a nonlinear map rather than a unitary operation, e.g., by replacing a beam-splitter-type coin with a two-mode squeezer, being a process that is controlled and driven by a pump field. This opens previously unattainable possibilities for quantum walks that include nonlinear elements as core components of their operation, vastly extending their range of applications. A full framework for driven Gaussian quantum walks is developed, including methods to dynamically characterize nonlinear, quantum, and quantum-nonlinear effects. Moreover, driven Gaussian quantum walks are compared with their classically interfering and linear counterparts, which are based on classical coherence of light rather than quantum superpositions. In particular, the generation and boost of highly multimode entanglement, squeezing, and other quantum effects are studied over the duration of the nonlinear walk. Importantly, we prove the quantumness of the evolution itself, regardless of the input state. A scheme for an experimental realization is proposed. Furthermore, nonlinear properties of driven Gaussian quantum walks are explored, such as amplification that leads to an ever increasing number of correlated quantum particles, constituting a source of new walkers during the walk. Therefore, a concept for quantum walks is proposed that leads to—and even produces—directly accessible quantum phenomena, and that renders the quantum simulation of nonlinear processes possible.}},
  author       = {{Held, Philip and Engelkemeier, Melanie and De, Syamsundar and Barkhofen, Sonja and Sperling, Jan and Silberhorn, Christine}},
  issn         = {{2469-9926}},
  journal      = {{Physical Review A}},
  number       = {{4}},
  publisher    = {{American Physical Society (APS)}},
  title        = {{{Driven Gaussian quantum walks}}},
  doi          = {{10.1103/physreva.105.042210}},
  volume       = {{105}},
  year         = {{2022}},
}

@techreport{53290,
  abstract     = {{In this report, we consider a semiconductor nanostructure in an optical cavity that is coupled to quantum light. We describe the semiconductor nanostructure with a parabolic band structure in a 1D k-space, while we assume a single-mode quantum field. The 1D<br> system is chosen for simplicity in both the analytical and the numerical treatment and paves the way for the description of 2D structures in the future. Therefore, instead of using parameters which are realistic for 1D systems, we rather use parameters which qualitatively correspond to 2D GaAs structures.}},
  author       = {{Rose, H. and Vasil'ev, A.N. and Tikhonova, O.V. and Meier, Torsten and Sharapova, Polina R.}},
  publisher    = {{LibreCat University}},
  title        = {{{Excitation of an electronic band structure by a single-photon Fock state}}},
  doi          = {{10.5281/ZENODO.5774985}},
  year         = {{2021}},
}

@misc{54403,
  abstract     = {{Dataset of the publication “Theoretical analysis and simulations of two-dimensional Fourier transform spectroscopy performed on exciton-polaritons of a quantum-well microcavity system“, H. Rose, J. Paul, J. K. Wahlstrand, A. Bristow, and T. Meier, Proceedings of the SPIE 11684, 1168414 (2021) ( https://doi.org/10.1117/12.2576696 ). The zip file includes the data on which the plots shown in figure 2 are based.}},
  author       = {{Rose, Hendrik and Paul, Jagannath and Wahlstrand, Jared K. and Bristow, Alan D. and Meier, Torsten}},
  publisher    = {{LibreCat University}},
  title        = {{{Theoretical analysis and simulations of two-dimensional Fourier transform spectroscopy performed on exciton-polaritons of a quantum-well microcavity system}}},
  doi          = {{10.5281/ZENODO.5153619}},
  year         = {{2021}},
}

@misc{54408,
  abstract     = {{Dataset of the publication “Accurate photon echo timing by optical freezing of exciton dephasing and rephasing in quantum dots“, ( https://doi.org/10.1038/s42005-020-00491-2 ). The zip file includes the data on which the plots shown in figures 2-5 of the main text, and supplementary figures S1-S5 are based.}},
  author       = {{Kosarev, Alexander and Rose, Hendrik and Poltavtsev, Sergey and Reichelt, Matthias and Schneider, Christian and Kamp, Martin and Höfling, Sven and Bayer, Manfred and Meier, Torsten and Akimov, Ilya}},
  publisher    = {{LibreCat University}},
  title        = {{{Accurate photon echo timing by optical freezing of exciton dephasing and rephasing in quantum dots}}},
  doi          = {{10.5281/ZENODO.5226662}},
  year         = {{2021}},
}

@misc{54402,
  abstract     = {{Dataset of the publication “Nondegenerate two-photon absorption in ZnSe: Experiment and theory“, L. Krauss-Kodytek, W.-R. Hannes, T. Meier, C. Ruppert, and M. Betz, Phys. Rev. B 104, 085201 (2021). ( https://doi.org/10.1103/PhysRevB.104.085201 ). The zip file includes the data on which the plots shown in figures 3, 4, and 5 are based.}},
  author       = {{Krauss-Kodytek, Laura and Hannes, Wolf-Rüdiger and Meier, Torsten and Ruppert, Claudia and Betz, Markus}},
  publisher    = {{LibreCat University}},
  title        = {{{Nondegenerate two-photon absorption in ZnSe: Experiment and theory}}},
  doi          = {{10.5281/ZENODO.5195116}},
  year         = {{2021}},
}

@misc{54404,
  abstract     = {{Dataset of the publication “Bright correlated twin-beam generation and radiation shaping in high-gain parametric down-conversion with anisotropy“, M. Riabinin, P. R. Sharapova, and T. Meier, Optics Express 29, 21876 (2021) ( https://doi.org/10.1364/OE.424977 ). The zip file includes the data on which the plots shown in figures 2, 3, 4, 6, 7, and 8 are based.}},
  author       = {{Riabinin, Matvei and Sharapova, Polina and Meier, Torsten}},
  publisher    = {{LibreCat University}},
  title        = {{{Bright correlated twin-beam generation and radiation shaping in high-gain parametric down-conversion with anisotropy}}},
  doi          = {{10.5281/ZENODO.5126748}},
  year         = {{2021}},
}

@misc{54401,
  abstract     = {{Dataset of the publication “Controlling the emission time of photon echoes by optical freezing of exciton dephasing and rephasing in quantum-dot ensembles“, Proc. SPIE 11684,116840X (2021) ( https://doi.org/10.1117/12.2576887 ). The zip file includes the data on which the figures are based, the gnuplot files for the figures, and an explaining readme.txt.}},
  author       = {{Reichelt, Matthias and Rose, Hendrik and Kosarev, Alexander N. and Poltavtsev, Sergey V. and Bayer, Manfred and Akimov, Ilya A. and Schneider, Christian and Kamp, Martin and Höfling, Sven and Meier, Torsten}},
  publisher    = {{LibreCat University}},
  title        = {{{Controlling the emission time of photon echoes by optical freezing of exciton dephasing and rephasing in quantum-dot ensembles}}},
  doi          = {{10.5281/ZENODO.5226911}},
  year         = {{2021}},
}

@misc{55559,
  abstract     = {{In this report, we consider a semiconductor nanostructure in an optical cavity that is coupled to quantum light. We describe the semiconductor nanostructure with a parabolic band structure in a 1D k-space, while we assume a single-mode quantum field. The 1D<br> system is chosen for simplicity in both the analytical and the numerical treatment and paves the way for the description of 2D structures in the future. Therefore, instead of using parameters which are realistic for 1D systems, we rather use parameters which qualitatively correspond to 2D GaAs structures.}},
  author       = {{Rose, Hendrik and Vasil'ev, A.N. and Tikhonova, O.V. and Meier, Torsten and Sharapova, Polina R.}},
  publisher    = {{LibreCat University}},
  title        = {{{Excitation of an electronic band structure by a single-photon Fock state}}},
  doi          = {{10.5281/ZENODO.5774986}},
  year         = {{2021}},
}