@article{27099,
  abstract     = {{In our work, we have engineered low capacitance single quantum dot photodiodes as sensor devices for the optoelectronic sampling of ultrafast electric signals. By the Stark effect, a time-dependent electric signal is converted into a time-dependent shift of the transition energy. This shift is measured accurately by resonant ps laser spectroscopy with photocurrent detection. In our experiments, we sample the laser synchronous output pulse of an ultrafast CMOS circuit with high resolution. With our quantum dot sensor device, we were able to sample transients below 20 ps with a voltage resolution in the mV-range.}},
  author       = {{Widhalm, Alex and Krehs, Sebastian and Siebert, Dustin and Sharma, Nand Lal and Langer, Timo and Jonas, Björn and Reuter, Dirk and Thiede, Andreas and Förstner, Jens and Zrenner, Artur}},
  issn         = {{0003-6951}},
  journal      = {{Applied Physics Letters}},
  keywords     = {{tet_topic_qd}},
  pages        = {{181109}},
  title        = {{{Optoelectronic sampling of ultrafast electric transients with single quantum dots}}},
  doi          = {{10.1063/5.0061358}},
  volume       = {{119}},
  year         = {{2021}},
}

@unpublished{32236,
  abstract     = {{The interaction between quantum light and matter is being intensively studied
for systems that are enclosed in high-$Q$ cavities which strongly enhance the
light-matter coupling. However, for many applications, cavities with lower
$Q$-factors are preferred due to the increased spectral width of the cavity
mode. Here, we investigate the interaction between quantum light and matter
represented by a $\Lambda$-type three-level system in lossy cavities, assuming
that cavity losses are the dominant loss mechanism. We demonstrate that cavity
losses lead to non-trivial steady states of the electronic occupations that can
be controlled by the loss rate and the initial statistics of the quantum
fields. The mechanism of formation of such steady states can be understood on
the basis of the equations of motion. Analytical expressions for steady states
and their numerical simulations are presented and discussed.}},
  author       = {{Rose, H. and Tikhonova, O. V. and Meier, T. and Sharapova, P. }},
  booktitle    = {{arXiv:2109.00842}},
  title        = {{{Steady states of $Λ$-type three-level systems excited by quantum  light in lossy cavities}}},
  year         = {{2021}},
}

@unpublished{29655,
  author       = {{Kirchgässner, Wilhelm and Wallscheid, Oliver and Böcker, Joachim}},
  booktitle    = {{arXiv preprint arXiv:2103.16323}},
  title        = {{{Thermal Neural Networks: Lumped-Parameter Thermal Modeling With State-Space Machine Learning}}},
  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{23477,
  author       = {{Thong, Le Huu and Ngo, Cong and Duc, Huynh Thanh and Song, Xiaohong and Meier, Torsten}},
  issn         = {{2469-9950}},
  journal      = {{Physical Review B}},
  pages        = {{085201}},
  title        = {{{Microscopic analysis of high harmonic generation in semiconductors with degenerate bands}}},
  doi          = {{10.1103/physrevb.103.085201}},
  volume       = {{103}},
  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{22008,
  author       = {{Plaickner, Julian and Speiser, Eugen and Braun, Christian and Schmidt, Wolf Gero and Esser, Norbert and Sanna, Simone}},
  issn         = {{2469-9950}},
  journal      = {{Physical Review B}},
  title        = {{{Surface localized phonon modes at the Si(553)-Au nanowire system}}},
  doi          = {{10.1103/physrevb.103.115441}},
  year         = {{2021}},
}

@article{40244,
  author       = {{Meier, Lukas and Schmidt, Wolf Gero}},
  issn         = {{0370-1972}},
  journal      = {{physica status solidi (b)}},
  keywords     = {{Condensed Matter Physics, Electronic, Optical and Magnetic Materials}},
  number       = {{1}},
  publisher    = {{Wiley}},
  title        = {{{GaInP/AlInP(001) Interfaces from Density Functional Theory}}},
  doi          = {{10.1002/pssb.202100462}},
  volume       = {{259}},
  year         = {{2021}},
}

@article{22009,
  author       = {{Ruiz Alvarado, Isaac Azahel and Karmo, Marsel and Runge, Erich and Schmidt, Wolf Gero}},
  issn         = {{2470-1343}},
  journal      = {{ACS Omega}},
  pages        = {{6297--6304}},
  title        = {{{InP and AlInP(001)(2 × 4) Surface Oxidation from Density Functional Theory}}},
  doi          = {{10.1021/acsomega.0c06019}},
  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{40434,
  author       = {{Klement, Philip and Dehnhardt, Natalie and Dong, Chuan-Ding and Dobener, Florian and Bayliff, Samuel and Winkler, Julius and Hofmann, Detlev M. and Klar, Peter J. and Schumacher, Stefan and Chatterjee, Sangam and Heine, Johanna}},
  issn         = {{0935-9648}},
  journal      = {{Advanced Materials}},
  keywords     = {{Mechanical Engineering, Mechanics of Materials, General Materials Science}},
  number       = {{23}},
  publisher    = {{Wiley}},
  title        = {{{Atomically Thin Sheets of Lead‐Free 1D Hybrid Perovskites Feature Tunable White‐Light Emission from Self‐Trapped Excitons}}},
  doi          = {{10.1002/adma.202100518}},
  volume       = {{33}},
  year         = {{2021}},
}

@article{24975,
  author       = {{Franz, Martin and Chandola, Sandhya and Koy, Maximilian and Zielinski, Robert and Aldahhak, Hazem and Das, Mowpriya and Freitag, Matthias and Gerstmann, Uwe and Liebig, Denise and Hoffmann, Adrian Karl and Rosin, Maximilian and Schmidt, Wolf Gero and Hogan, Conor and Glorius, Frank and Esser, Norbert and Dähne, Mario}},
  issn         = {{1755-4330}},
  journal      = {{Nature Chemistry}},
  pages        = {{828--835}},
  title        = {{{Controlled growth of ordered monolayers of N-heterocyclic carbenes on silicon}}},
  doi          = {{10.1038/s41557-021-00721-2}},
  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}},
}

@inproceedings{23475,
  author       = {{Rose, Hendrik and Paul, Jagannath and Wahlstrand, Jared K. and Bristow, Alan D. and Meier, Torsten}},
  booktitle    = {{Ultrafast Phenomena and Nanophotonics XXV}},
  editor       = {{Betz, Markus and Elezzabi, Abdulhakem Y.}},
  title        = {{{Theoretical analysis and simulations of two-dimensional Fourier transform spectroscopy performed on exciton-polaritons of a quantum-well microcavity system}}},
  doi          = {{10.1117/12.2576696}},
  volume       = {{11684}},
  year         = {{2021}},
}