@article{28413,
  abstract     = {{Optical traveling wave antennas offer unique opportunities to control and selectively guide light into a specific direction, which renders them excellent candidates for optical communication and sensing. These applications require state-of-the-art engineering to reach optimized functionalities such as high directivity and radiation efficiency, low sidelobe levels, broadband and tunable capabilities, and compact design. In this work, we report on the numerical optimization of the directivity of optical traveling wave antennas made from low-loss dielectric materials using full-wave numerical simulations in conjunction with the particle swarm optimization algorithm. The antennas are composed of a reflector and a director deposited on a glass substrate, and an emitter placed in the feed gap between them serves as an internal source of excitation. In particular, we analyze antennas with rectangular- and horn-shaped directors made of either hafnium dioxide or silicon. The optimized antennas produce highly directional emissions due to the presence of two dominant guided TE modes in the director in addition to leaky modes. These guided modes dominate the far-field emission pattern and govern the direction of the main lobe emission, which predominately originates from the end facet of the director. Our work also provides a comprehensive analysis of the modes, radiation patterns, parametric influences, and bandwidths of the antennas, which highlights their robust nature.}},
  author       = {{Farheen, Henna and Leuteritz, Till and Linden, Stefan and Myroshnychenko, Viktor and Förstner, Jens}},
  issn         = {{0740-3224}},
  journal      = {{Journal of the Optical Society of America B}},
  keywords     = {{tet_topic_opticalantenna}},
  number       = {{1}},
  pages        = {{83}},
  title        = {{{Optimization of optical waveguide antennas for directive emission of light}}},
  doi          = {{10.1364/josab.438514}},
  volume       = {{39}},
  year         = {{2022}},
}

@article{29075,
  abstract     = {{We study a double-scattering coherent mechanism of negative polarization (NP) near opposition that is observed for powder-like surfaces. The problem is solved numerically for absorbing structures with irregular constituents, cubes, spheres, and ellipsoids larger than the wavelength of incident light. Our simulations show that double scattering between two random irregular particles shows weak NP. Adding one more particle significantly increases the relative contribution of double scattering which enhances NP. Simulations with regular shapes and controlled geometric parameters show that the interference mechanism is sensitive to the geometry of the scattering system and can also result in no polarization or even strong enhancement of positive polarization at backscattering.}},
  author       = {{Alhaddad, Samer and Grynko, Yevgen and Farheen, Henna and Förstner, Jens}},
  issn         = {{0146-9592}},
  journal      = {{Optics Letters}},
  keywords     = {{tet_topic_scattering}},
  number       = {{1}},
  pages        = {{58}},
  title        = {{{Numerical analysis of the coherent mechanism producing negative polarization at backscattering from systems of absorbing particles}}},
  doi          = {{10.1364/ol.444953}},
  volume       = {{47}},
  year         = {{2022}},
}

@article{31329,
  abstract     = {{Highly directive antennas with the ability of shaping radiation patterns in desired directions are essential for efficient on-chip optical communication with reduced cross talk. In this paper, we design and optimize three distinct broadband traveling-wave tantalum pentoxide antennas exhibiting highly directional characteristics. Our antennas contain a director and reflector deposited on a glass substrate, which are excited by a dipole emitter placed in the feed gap between the two elements. Full-wave simulations in conjunction with global optimization provide structures with an enhanced linear directivity as high as 119 radiating in the substrate. The high directivity is a result of the interplay between two dominant TE modes and the leaky modes present in the antenna director. Furthermore, these low-loss dielectric antennas exhibit a near-unity radiation efficiency at the operational wavelength of 780 nm and maintain a broad bandwidth. Our numerical results are in good agreement with experimental measurements from the optimized antennas fabricated using a two-step electron-beam lithography, revealing the highly directive nature of our structures. We envision that our antenna designs can be conveniently adapted to other dielectric materials and prove instrumental for inter-chip optical communications and other on-chip applications.}},
  author       = {{Farheen, Henna and Yan, Lok-Yee and Quiring, Viktor and Eigner, Christof and Zentgraf, Thomas and Linden, Stefan and Förstner, Jens and Myroshnychenko, Viktor}},
  issn         = {{1094-4087}},
  journal      = {{Optics Express}},
  keywords     = {{tet_topic_opticalantenna}},
  number       = {{11}},
  pages        = {{19288}},
  publisher    = {{Optica Publishing Group}},
  title        = {{{Broadband optical Ta2O5 antennas for directional emission of light}}},
  doi          = {{10.1364/oe.455815}},
  volume       = {{30}},
  year         = {{2022}},
}

@article{36804,
  author       = {{Henksmeier, Tobias and Schulz, Johann Friedemann and Kluth, Elias and Feneberg, Martin and Goldhahn, Rüdiger and Sanchez, Ana M. and Voigt, Markus and Grundmeier, Guido and Reuter, Dirk}},
  journal      = {{Journal of Crystal Growth}},
  publisher    = {{Elsevier}},
  title        = {{{Remote epitaxy of In(x)Ga(1-x)As(001) on graphene covered GaAs(001) substrates}}},
  doi          = {{10.1016/j.jcrysgro.2022.126756}},
  volume       = {{593}},
  year         = {{2022}},
}

@article{34237,
  author       = {{Kruse, Stephan and Gudyriev, Sergiy and Kneuper, Pascal and Schwabe, Tobias and Meinecke, Marc-Michael and Kurz, Heiko G. and Scheytt, J. Christoph}},
  issn         = {{1531-1309}},
  journal      = {{IEEE Microwave and Wireless Components Letters}},
  number       = {{12}},
  pages        = {{1447--1450}},
  publisher    = {{Institute of Electrical and Electronics Engineers (IEEE)}},
  title        = {{{Silicon Photonic Radar Receiver IC for mm-Wave Large Aperture MIMO Radar Using Optical Clock Distribution}}},
  doi          = {{10.1109/lmwc.2022.3186432}},
  volume       = {{32}},
  year         = {{2022}},
}

@article{40273,
  author       = {{Meyer-Scott, Evan and Prasannan, Nidhin and Dhand, Ish and Eigner, Christof and Quiring, Viktor and Barkhofen, Sonja and Brecht, Benjamin and Plenio, Martin B. and Silberhorn, Christine}},
  issn         = {{0031-9007}},
  journal      = {{Physical Review Letters}},
  keywords     = {{General Physics and Astronomy}},
  number       = {{15}},
  publisher    = {{American Physical Society (APS)}},
  title        = {{{Scalable Generation of Multiphoton Entangled States by Active Feed-Forward and Multiplexing}}},
  doi          = {{10.1103/physrevlett.129.150501}},
  volume       = {{129}},
  year         = {{2022}},
}

@article{28254,
  abstract     = {{With the rapid advances of functional dielectric metasurfaces and their integration on on-chip nanophotonic devices, the necessity of metasurfaces working in different environments, especially in biological applications, arose. However, the metasurfaces’ performance is tied to the unit cell’s efficiency and ultimately the surrounding environment it was designed for, thus reducing its applicability if exposed to altering refractive index media. Here, we report a method to increase a metasurface’s versatility by covering the high-index metasurface with a low index porous SiO2 film, protecting the metasurface from environmental changes while keeping the working efficiency unchanged. We show, that a covered metasurface retains its functionality even when exposed to fluidic environments.}},
  author       = {{Geromel, René and Weinberger, Christian and Brormann, Katja and Tiemann, Michael and Zentgraf, Thomas}},
  issn         = {{2159-3930}},
  journal      = {{Optical Materials Express}},
  number       = {{1}},
  pages        = {{13--21}},
  publisher    = {{Optica}},
  title        = {{{Porous SiO2 coated dielectric metasurface with consistent performance independent of environmental conditions}}},
  doi          = {{10.1364/ome.444264}},
  volume       = {{12}},
  year         = {{2022}},
}

@article{37318,
  abstract     = {{<jats:title>Abstract</jats:title>
               <jats:p>The interaction between quantum light and matter is being intensively studied for systems that are enclosed in high-<jats:italic>Q</jats:italic> cavities which strongly enhance the light–matter coupling. Cavities with low <jats:italic>Q</jats:italic>-factors are generally given less attention due to their high losses that quickly destroy quantum systems. However, bad cavities can be utilized for several applications, where lower <jats:italic>Q</jats:italic>-factors are required, e.g., to increase the spectral width of the cavity mode. In this work, we demonstrate that low-<jats:italic>Q</jats:italic> cavities can be beneficial for preparing specific electronic steady states when certain quantum states of light are applied. We investigate the interaction between quantum light with various statistics and matter represented by a Λ-type three-level system in lossy cavities, assuming that cavity losses are the dominant loss mechanism. We show that cavity losses lead to non-trivial electronic steady states that can be controlled by the loss rate and the initial statistics of the quantum fields. We discuss the mechanism of the formation of such steady states on the basis of the equations of motion and present both analytical expressions and numerical simulations for such steady states.</jats:p>}},
  author       = {{Rose, Hendrik and Tikhonova, O V and Meier, Torsten and Sharapova, Polina}},
  issn         = {{1367-2630}},
  journal      = {{New Journal of Physics}},
  keywords     = {{General Physics and Astronomy}},
  number       = {{6}},
  publisher    = {{IOP Publishing}},
  title        = {{{Steady states of Λ-type three-level systems excited by quantum light with various photon statistics in lossy cavities}}},
  doi          = {{10.1088/1367-2630/ac74d8}},
  volume       = {{24}},
  year         = {{2022}},
}

@article{37319,
  author       = {{Grisard, S. and Rose, Hendrik and Trifonov, A. V. and Reichhardt, R. and Reiter, D. E. and Reichelt, Matthias and Schneider, C. and Kamp, M. and Höfling, S. and Bayer, M. and Meier, Torsten and Akimov, I. A.}},
  issn         = {{2469-9950}},
  journal      = {{Physical Review B}},
  number       = {{20}},
  publisher    = {{American Physical Society (APS)}},
  title        = {{{Multiple Rabi rotations of trions in InGaAs quantum dots observed by photon echo spectroscopy with spatially shaped laser pulses}}},
  doi          = {{10.1103/physrevb.106.205408}},
  volume       = {{106}},
  year         = {{2022}},
}

@inproceedings{37329,
  author       = {{Trautmann, Alexander and Zuo, Ruixin and Wang, Guifang and Hannes, Wolf-Rüdiger and Yang, Shidong and Thong, Le Huu and Ngo, Cong and Steiner, Johannes and Ciappina, Marcelo and Reichelt, Matthias and Duc, Huynh Thanh and Song, Xiaohong and Yang, Weifeng and Meier, Torsten}},
  booktitle    = {{Ultrafast Phenomena and Nanophotonics XXVI}},
  editor       = {{Betz, Markus and Elezzabi, Abdulhakem Y.}},
  title        = {{{Microscopic simulations of high harmonic generation from semiconductors}}},
  doi          = {{10.1117/12.2607447}},
  volume       = {{11999}},
  year         = {{2022}},
}

@inproceedings{37327,
  author       = {{Rose, Hendrik and Tikhonova, Olga V. and Meier, Torsten and Sharapova, Polina}},
  booktitle    = {{Ultrafast Phenomena and Nanophotonics XXVI}},
  editor       = {{Betz, Markus and Elezzabi, Abdulhakem Y.}},
  title        = {{{Theoretical analysis of correlations between two quantum fields exciting a three-level system using the cluster-expansion approach}}},
  doi          = {{10.1117/12.2608528}},
  volume       = {{11999}},
  year         = {{2022}},
}

@article{37323,
  author       = {{Paul, J. and Rose, Hendrik and Swagel, E. and Meier, Torsten and Wahlstrand, J. K. and Bristow, A. D.}},
  issn         = {{2469-9950}},
  journal      = {{Physical Review B}},
  number       = {{11}},
  publisher    = {{American Physical Society (APS)}},
  title        = {{{Coherent contributions to population dynamics in a semiconductor microcavity}}},
  doi          = {{10.1103/physrevb.105.115307}},
  volume       = {{105}},
  year         = {{2022}},
}

@unpublished{37325,
  author       = {{Meier, Torsten and Ali, Usman}},
  booktitle    = {{Condensed Matter}},
  title        = {{{Super-Bloch oscillations with parametric modulation of a parabolic trap}}},
  year         = {{2022}},
}

@article{40523,
  abstract     = {{<jats:title>Abstract</jats:title><jats:p>Tailored nanoscale quantum light sources, matching the specific needs of use cases, are crucial building blocks for photonic quantum technologies. Several different approaches to realize solid-state quantum emitters with high performance have been pursued and different concepts for energy tuning have been established. However, the properties of the emitted photons are always defined by the individual quantum emitter and can therefore not be controlled with full flexibility. Here we introduce an all-optical nonlinear method to tailor and control the single photon emission. We demonstrate a laser-controlled down-conversion process from an excited state of a semiconductor quantum three-level system. Based on this concept, we realize energy tuning and polarization control of the single photon emission with a control-laser field. Our results mark an important step towards tailored single photon emission from a photonic quantum system based on quantum optical principles.</jats:p>}},
  author       = {{Jonas, B. and Heinze, Dirk Florian and Schöll, E. and Kallert, P. and Langer, T. and Krehs, S. and Widhalm, A. and Jöns, Klaus and Reuter, Dirk and Schumacher, Stefan and Zrenner, Artur}},
  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        = {{{Nonlinear down-conversion in a single quantum dot}}},
  doi          = {{10.1038/s41467-022-28993-3}},
  volume       = {{13}},
  year         = {{2022}},
}

@article{40431,
  author       = {{Praschan, Tom and Heinze, Dirk and Breddermann, Dominik and Zrenner, Artur and Walther, Andrea and Schumacher, Stefan}},
  issn         = {{2469-9950}},
  journal      = {{Physical Review B}},
  number       = {{4}},
  publisher    = {{American Physical Society (APS)}},
  title        = {{{Pulse shaping for on-demand emission of single Raman photons from a quantum-dot biexciton}}},
  doi          = {{10.1103/physrevb.105.045302}},
  volume       = {{105}},
  year         = {{2022}},
}

@misc{40428,
  author       = {{Jonas, Björn and Heinze, Dirk Florian and Schöll, Eva and Kallert, Patricia and Langer, Timo and Krehs, Sebastian and Widhalm, Alex and Jöns, Klaus and Reuter, Dirk and Zrenner, Artur}},
  publisher    = {{LibreCat University}},
  title        = {{{Nonlinear down-conversion in a single quantum dot}}},
  doi          = {{10.5281/ZENODO.6024228}},
  year         = {{2022}},
}

@article{37711,
  abstract     = {{<jats:title>Abstract</jats:title><jats:p>Polarons influence decisively the performance of lithium niobate for optical applications. In this work, the formation of (defect) bound polarons in lithium niobate is studied by ab initio molecular dynamics. The calculations show a broad scatter of polaron formation times. Rising temperature increases the share of trajectories with long formation times, which leads to an overall increase of the average formation time with temperature. However, even at elevated temperatures, the average formation time does not exceed the value of 100 femtoseconds, i.e., a value close to the time measured for free, i.e., self-trapped polarons. Analyzing individual trajectories, it is found that the time required for the structural relaxation of the polarons depends sensitively on the excitation of the lithium niobate high-frequency phonon modes and their phase relation.</jats:p>}},
  author       = {{Krenz, Marvin and Gerstmann, Uwe and Schmidt, Wolf Gero}},
  issn         = {{0947-8396}},
  journal      = {{Applied Physics A}},
  keywords     = {{General Materials Science, General Chemistry}},
  pages        = {{480}},
  publisher    = {{Springer Science and Business Media LLC}},
  title        = {{{Bound polaron formation in lithium niobate from ab initio molecular dynamics}}},
  doi          = {{10.1007/s00339-022-05577-y}},
  volume       = {{128}},
  year         = {{2022}},
}

@inproceedings{43744,
  abstract     = {{We demonstrate theoretically and experimentally complex correlations in the photon numbers of two-mode quantum states using measurement-induced nonlinearity. For this, we combine the interference of coherent states and single photons with photon sub-traction.}},
  author       = {{Meier, Torsten and Hoepker, Jan Philipp and Protte, Maximilian and Eigner, Christof and Silberhorn, Christine and Sharapova, Polina R. and Sperling, Jan and Bartley, Tim}},
  booktitle    = {{Conference on Lasers and Electro-Optics: Applications and Technology}},
  isbn         = {{978-1-957171-05-0}},
  location     = {{San Jose, California United States}},
  pages        = {{JTu3A. 17}},
  publisher    = {{Optica Publishing Group}},
  title        = {{{Two-Mode Photon-Number Correlations Created by Measurement-Induced Nonlinearity}}},
  doi          = {{10.1364/CLEO_AT.2022.JTu3A.17}},
  year         = {{2022}},
}

@article{33484,
  abstract     = {{We study the DC conductivity in potassium titanyl phosphate (KTiOPO4, KTP) and its isomorphs KTiOAsO4 (KTA) and Rb1%K99%TiOPO4 (RKTP) and introduce a method by which to reduce the overall ionic conductivity in KTP by a potassium nitrate treatment. Furthermore, we create so-called gray tracking in KTP and investigate the ionic conductivity in theses areas. A local unintended reduction of the ionic conductivity is observed in the gray-tracked regions, which also induce additional optical absorption in the material. We show that a thermal treatment in an oxygen-rich atmosphere removes the gray tracking and brings the ionic conductivity as well as the optical transmission back to the original level. These studies can help to choose the best material and treatment for specific applications.}},
  author       = {{Padberg, Laura and Quiring, Viktor and Bocchini, Adriana and Santandrea, Matteo and Gerstmann, Uwe and Schmidt, Wolf Gero and Silberhorn, Christine and Eigner, Christof}},
  issn         = {{2073-4352}},
  journal      = {{Crystals}},
  pages        = {{1359}},
  title        = {{{DC Ionic Conductivity in KTP and Its Isomorphs: Properties, Methods for Suppression, and Its Connection to Gray Tracking}}},
  doi          = {{10.3390/cryst12101359}},
  volume       = {{12}},
  year         = {{2022}},
}

@inproceedings{30389,
  abstract     = {{Online solvers for a series of standard 1-D or 2-D problems in integrated optics will be discussed. Implemented on the basis of HTML/JavaScript/SVG with core routines compiled from well tested C++-sources, the quasi-analytical algorithms require a computational load that can be handled easily even by current mobile devices. So far the series covers the 1-D guided modes of dielectric multilayer slab waveguides and the oblique plane wave reflection from these, the modes of rectangular channel waveguides (in an approximation of effective indices), bend modes of curved multilayer slabs, whispering-gallery resonances (“Quasi-Normal-Modes”) supported by circular dielectric cavities, the hybrid modes of circular multi-step-index optical fibers, bound and leaky modes of 1-D complex multilayers, including plasmonic surface modes, and, with restrictions, quite general rectangular scattering problems in 2-D.}},
  author       = {{Hammer, Manfred}},
  booktitle    = {{Integrated Optics: Devices, Materials, and Technologies XXVI}},
  editor       = {{García-Blanco, Sonia M. and Cheben, Pavel}},
  keywords     = {{tet_topic_waveguide}},
  pages        = {{1200414}},
  publisher    = {{SPIE}},
  title        = {{{Small-scale online simulations in guided-wave photonics}}},
  doi          = {{10.1117/12.2612208}},
  year         = {{2022}},
}