@article{23843,
  author       = {{Meier, F. and Protte, M. and Baron, E. and Feneberg, M. and Goldhahn, R. and Reuter, Dirk and As, Donat Josef}},
  issn         = {{2158-3226}},
  journal      = {{AIP Advances}},
  title        = {{{Selective area growth of cubic gallium nitride on silicon (001) and 3C-silicon carbide (001)}}},
  doi          = {{10.1063/5.0053865}},
  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{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}},
}

@article{21821,
  abstract     = {{We present a combined experimental and numerical study of the far-field emission properties of optical travelling wave antennas made from low-loss dielectric materials. The antennas considered here are composed of two simple building blocks, a director and a reflector, deposited on a glass substrate. Colloidal quantum dots placed in the feed gap between the two elements serve as internal light source. The emission profile of the antenna is mainly formed by the director while the reflector suppresses backward emission. Systematic studies of the director dimensions as well as variation of antenna material show that the effective refractive index of the director primarily governs the far-field emission pattern. Below cut off, i.e., if the director’s effective refractive index is smaller than the refractive index of the substrate, the main lobe results from leaky wave emission along the director. In contrast, if the director supports a guided mode, the emission predominately originates from the end facet of the director.}},
  author       = {{Leuteritz, T. and Farheen, Henna and Qiao, S. and Spreyer, F. and Schlickriede, Christian and Zentgraf, Thomas and Myroshnychenko, Viktor and Förstner, Jens and Linden, S.}},
  issn         = {{1094-4087}},
  journal      = {{Optics Express}},
  keywords     = {{tet_topic_opticalantenna}},
  number       = {{10}},
  title        = {{{Dielectric travelling wave antennas for directional light emission}}},
  doi          = {{10.1364/oe.422984}},
  volume       = {{29}},
  year         = {{2021}},
}

@article{26889,
  author       = {{Luo, Kai Hong and Santandrea, Matteo and Stefszky, Michael and Sperling, Jan and Massaro, Marcello and Ferreri, Alessandro and Sharapova, Polina and Herrmann, Harald and Silberhorn, Christine}},
  issn         = {{2469-9926}},
  journal      = {{Physical Review A}},
  title        = {{{Quantum optical coherence: From linear to nonlinear interferometers}}},
  doi          = {{10.1103/physreva.104.043707}},
  year         = {{2021}},
}

@article{26283,
  author       = {{Lüders, Carolin and Pukrop, Matthias and Rozas, Elena and Schneider, Christian and Höfling, Sven and Sperling, Jan and Schumacher, Stefan and Aßmann, Marc}},
  issn         = {{2691-3399}},
  journal      = {{PRX Quantum}},
  title        = {{{Quantifying Quantum Coherence in Polariton Condensates}}},
  doi          = {{10.1103/prxquantum.2.030320}},
  year         = {{2021}},
}

@article{29748,
  author       = {{Slawig, Diana and Gruschwitz, Markus and Gerstmann, Uwe and Rauls, Eva and Tegenkamp, Christoph}},
  issn         = {{1932-7447}},
  journal      = {{The Journal of Physical Chemistry C}},
  keywords     = {{Surfaces, Coatings and Films, Physical and Theoretical Chemistry, General Energy, Electronic, Optical and Magnetic Materials}},
  number       = {{36}},
  pages        = {{20087--20093}},
  publisher    = {{American Chemical Society (ACS)}},
  title        = {{{Adsorption and Reaction of PbPc on Hydrogenated Epitaxial Graphene}}},
  doi          = {{10.1021/acs.jpcc.1c06320}},
  volume       = {{125}},
  year         = {{2021}},
}

@article{37331,
  abstract     = {{<jats:p>High harmonic generation (HHG) from solids shows great application prospects in compact short-wavelength light sources and as a tool for imaging the dynamics in crystals with subnanometer spatial and attosecond temporal resolution. However, the underlying collision dynamics behind solid HHG is still intensively debated and no direct mapping relationship between the collision dynamics with band structure has been built. Here, we show that the electron and its associated hole can be elastically scattered by neighboring atoms when their wavelength approaches the atomic size. We reveal that the elastic scattering of electron/hole from neighboring atoms can dramatically influence the electron recombination with its left-behind hole, which turns out to be the fundamental reason for the anisotropic interband HHG observed recently in bulk crystals. Our findings link the electron/hole backward scattering with Van Hove singularities and forward scattering with critical lines in the band structure and thus build a clear mapping between the band structure and the harmonic spectrum. Our work provides a unifying picture for several seemingly unrelated experimental observations and theoretical predictions, including the anisotropic harmonic emission in MgO, the atomic-like recollision mechanism of solid HHG, and the delocalization of HHG in ZnO. This strongly improved understanding will pave the way for controlling the solid-state HHG and visualizing the structure-dependent electron dynamics in solids.</jats:p>}},
  author       = {{Zuo, Ruixin and Trautmann, Alexander and Wang, Guifang and Hannes, Wolf-Rüdiger and Yang, Shidong and Song, Xiaohong and Meier, Torsten and Ciappina, Marcelo and Duc, Huynh Thanh and Yang, Weifeng}},
  issn         = {{2765-8791}},
  journal      = {{Ultrafast Science}},
  publisher    = {{American Association for the Advancement of Science (AAAS)}},
  title        = {{{Neighboring Atom Collisions in Solid-State High Harmonic Generation}}},
  doi          = {{10.34133/2021/9861923}},
  volume       = {{2021}},
  year         = {{2021}},
}

@article{37338,
  abstract     = {{<jats:title>Abstract</jats:title><jats:p>Methylammonium lead iodide perovskite (MAPbI<jats:sub>3</jats:sub>) is renowned for an impressive power conversion efficiency rise and cost-effective fabrication for photovoltaics. In this work, we demonstrate that polycrystalline MAPbI<jats:sub>3</jats:sub>s undergo drastic changes in optical properties at moderate field strengths with an ultrafast response time, via transient Wannier Stark localization. The distinct band structure of this material - the large lattice periodicity, the narrow electronic energy bandwidths, and the coincidence of these two along the same high-symmetry direction – enables relatively weak fields to bring this material into the Wannier Stark regime. Its polycrystalline nature is not detrimental to the optical switching performance of the material, since the least dispersive direction of the band structure dominates the contribution to the optical response, which favors low-cost fabrication. Together with the outstanding photophysical properties of MAPbI<jats:sub>3</jats:sub>, this finding highlights the great potential of this material in ultrafast light modulation and novel photonic applications.</jats:p>}},
  author       = {{Berghoff, Daniel and Bühler, Johannes and Bonn, Mischa and Leitenstorfer, Alfred and Meier, Torsten and Kim, Heejae}},
  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        = {{{Low-field onset of Wannier-Stark localization in a polycrystalline hybrid organic inorganic perovskite}}},
  doi          = {{10.1038/s41467-021-26021-4}},
  volume       = {{12}},
  year         = {{2021}},
}

@article{21946,
  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}},
  issn         = {{2073-4352}},
  journal      = {{Crystals}},
  pages        = {{542}},
  publisher    = {{MDPI}},
  title        = {{{Electron polarons in lithium niobate: Charge localization, lattice deformation, and optical response}}},
  doi          = {{10.3390/cryst11050542}},
  volume       = {{11}},
  year         = {{2021}},
}

@inproceedings{23474,
  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}},
  booktitle    = {{Ultrafast Phenomena and Nanophotonics XXV}},
  editor       = {{Betz, Markus and Elezzabi, Abdulhakem Y.}},
  title        = {{{Controlling the emission time of photon echoes by optical freezing of exciton dephasing and rephasing in quantum-dot ensembles}}},
  doi          = {{10.1117/12.2576887}},
  volume       = {{11684}},
  year         = {{2021}},
}

@article{22881,
  author       = {{Nguyen, T. T. Nhung and Sollfrank, T. and Tegenkamp, C. and Rauls, E. and Gerstmann, Uwe}},
  issn         = {{2469-9950}},
  journal      = {{Physical Review B}},
  pages        = {{L201408}},
  title        = {{{Impact of screening and relaxation on weakly coupled two-dimensional heterostructures}}},
  doi          = {{10.1103/physrevb.103.l201408}},
  volume       = {{103}},
  year         = {{2021}},
}

@article{22310,
  author       = {{Neufeld, Sergej and Bocchini, Adriana and Schmidt, Wolf Gero}},
  issn         = {{2475-9953}},
  journal      = {{Physical Review Materials}},
  title        = {{{Potassium titanyl phosphate Z- and Y-cut surfaces from density-functional theory}}},
  doi          = {{10.1103/physrevmaterials.5.064407}},
  year         = {{2021}},
}

@article{22960,
  abstract     = {{We perform a theoretical analysis of the structural and electronic properties of sodium potassium niobate K1-xNaxNbO3 in the orthorhombic room-temperature phase, based on density-functional theory in combination with the supercell approach. Our results for x=0 and x=0.5 are in very good agreement with experimental measurements and establish that the lattice parameters decrease linearly with increasing Na contents, disproving earlier theoretical studies based on the virtual-crystal approximation that claimed a highly nonlinear behavior with a significant structural distortion and volume reduction in K0.5Na0.5NbO3 compared to both end members of the solid solution. Furthermore, we find that the electronic band gap varies very little between x=0 and x=0.5, reflecting the small changes in the lattice parameters.}},
  author       = {{Bidaraguppe Ramesh, Nithin and Schmidt, Falko and Schindlmayr, Arno}},
  issn         = {{1434-6036}},
  journal      = {{The European Physical Journal B}},
  number       = {{8}},
  publisher    = {{EDP Sciences, Società Italiana di Fisica and Springer}},
  title        = {{{Lattice parameters and electronic band gap of orthorhombic potassium sodium niobate K0.5Na0.5NbO3 from density-functional theory}}},
  doi          = {{10.1140/epjb/s10051-021-00179-8}},
  volume       = {{94}},
  year         = {{2021}},
}

@article{37334,
  abstract     = {{<jats:p>Uniaxial anisotropy in nonlinear birefringent crystals limits the efficiency of nonlinear optical interactions and breaks the spatial symmetry of light generated in the parametric down-conversion (PDC) process. Therefore, this effect is usually undesirable and must be compensated for. However, high gain may be used to overcome the destructive role of anisotropy in order to generate bright two-mode correlated twin-beams. In this work, we provide a rigorous theoretical description of the spatial properties of bright squeezed light in the presence of strong anisotropy. We investigate a single crystal and a system of two crystals with an air gap (corresponding to a nonlinear SU(1,1) interferometer) and demonstrate the generation of bright correlated twin-beams in such configurations at high gain due to anisotropy. We explore the mode structure of the generated light and show how anisotropy, together with crystal spacing, can be used for radiation shaping.</jats:p>}},
  author       = {{Riabinin, M. and Sharapova, Polina and Meier, Torsten}},
  issn         = {{1094-4087}},
  journal      = {{Optics Express}},
  keywords     = {{Atomic and Molecular Physics, and Optics}},
  number       = {{14}},
  pages        = {{21876--21890}},
  publisher    = {{Optica Publishing Group}},
  title        = {{{Bright correlated twin-beam generation and radiation shaping in high-gain parametric down-conversion with anisotropy}}},
  doi          = {{10.1364/oe.424977}},
  volume       = {{29}},
  year         = {{2021}},
}

@article{23816,
  abstract     = {{Employing the ultrafast control of electronic states of a semiconductor quantum dot in a cavity, we introduce an approach to achieve on-demand emission of single photons with almost perfect indistinguishability and photon pairs with near ideal entanglement. Our scheme is based on optical excitation off resonant to a cavity mode followed by ultrafast control of the electronic states using the time-dependent quantum-confined Stark effect, which then allows for cavity-resonant emission. Our theoretical analysis considers cavity-loss mechanisms, the Stark effect, and phonon-induced dephasing, allowing realistic predictions for finite temperatures.}},
  author       = {{Bauch, David and Heinze, Dirk Florian and Förstner, Jens and Jöns, Klaus and Schumacher, Stefan}},
  issn         = {{2469-9950}},
  journal      = {{Physical Review B}},
  keywords     = {{tet_topic_qd}},
  pages        = {{085308}},
  title        = {{{Ultrafast electric control of cavity mediated single-photon and photon-pair generation with semiconductor quantum dots}}},
  doi          = {{10.1103/physrevb.104.085308}},
  volume       = {{104}},
  year         = {{2021}},
}

@article{23418,
  abstract     = {{Density-functional theory within a Berry-phase formulation of the dynamical polarization is used to determine the second-order susceptibility χ(2) of lithium niobate (LiNbO3). Defect trapped polarons and bipolarons are found to strongly enhance the nonlinear susceptibility of the material, in particular if localized at NbV–VLi defect pairs. This is essentially a consequence of the polaronic excitation resulting in relaxation-induced gap states. The occupation of these levels leads to strongly enhanced χ(2) coefficients and allows for the spatial and transient modification of the second-harmonic generation of macroscopic samples.}},
  author       = {{Kozub, Agnieszka L. and Schindlmayr, Arno and Gerstmann, Uwe and Schmidt, Wolf Gero}},
  issn         = {{2469-9969}},
  journal      = {{Physical Review B}},
  pages        = {{174110}},
  publisher    = {{American Physical Society}},
  title        = {{{Polaronic enhancement of second-harmonic generation in lithium niobate}}},
  doi          = {{10.1103/PhysRevB.104.174110}},
  volume       = {{104}},
  year         = {{2021}},
}

@article{37333,
  author       = {{Krauss-Kodytek, L. and Hannes, W.-R. and Meier, Torsten and Ruppert, C. and Betz, M.}},
  issn         = {{2469-9950}},
  journal      = {{Physical Review B}},
  number       = {{8}},
  publisher    = {{American Physical Society (APS)}},
  title        = {{{Nondegenerate two-photon absorption in ZnSe: Experiment and theory}}},
  doi          = {{10.1103/physrevb.104.085201}},
  volume       = {{104}},
  year         = {{2021}},
}

@article{21547,
  author       = {{Riabinin, Matvei and Sharapova, Polina and Bartley, Tim and Meier, Torsten}},
  issn         = {{2399-6528}},
  journal      = {{Journal of Physics Communications}},
  number       = {{4}},
  title        = {{{Generating two-mode squeezing with multimode measurement-induced nonlinearity}}},
  doi          = {{10.1088/2399-6528/abeec2}},
  volume       = {{5}},
  year         = {{2021}},
}

@article{23472,
  author       = {{Krauss-Kodytek, L. and Hannes, Wolf-Rüdiger and Meier, Torsten and Ruppert, C. and Betz, M.}},
  issn         = {{2469-9950}},
  journal      = {{Physical Review B}},
  number       = {{8}},
  title        = {{{Nondegenerate two-photon absorption in ZnSe: Experiment and theory}}},
  doi          = {{10.1103/physrevb.104.085201}},
  volume       = {{104}},
  year         = {{2021}},
}