@article{6522, abstract = {{An electric field applied to a semiconductor reduces its crystal symmetry and modifies its electronic structure which is expected to result in changes of the linear and nonlinear response to optical excitation. In GaAs, we observe experimentally strong electric field effects on the optical second (SHG) and third (THG) harmonic generation. The SHG signal for the laser-light k vector parallel to the [001] crystal axis is symmetry forbidden in the electric-dipole approximation, but can be induced by an applied electric field in the vicinity of the 1s exciton energy. Surprisingly, the THG signal, which is allowed in this geometry, is considerably reduced by the electric field. We develop a theory which provides good agreement with the experimental data. In particular, it shows that the optical nonlinearities for the 1s exciton resonance are modified in an electric field by the Stark effect, which mixes the 1s and 2p exciton states of opposite parity. This mixing acts in opposite way on the SHG and THG processes, as it leads to the appearance of forbidden SHG in (001)-oriented GaAs and decreases the crystallographic THG.}}, author = {{Brunne, D. and Lafrentz, M. and Pavlov, V. V. and Pisarev, R. V. and Rodina, A. V. and Yakovlev, D. R. and Bayer, M.}}, issn = {{1098-0121}}, journal = {{Physical Review B}}, number = {{8}}, publisher = {{American Physical Society (APS)}}, title = {{{Electric field effect on optical harmonic generation at the exciton resonances in GaAs}}}, doi = {{10.1103/physrevb.92.085202}}, volume = {{92}}, year = {{2015}}, } @article{6524, abstract = {{We use a picosecond acoustics technique to modulate the laser output of electrically pumped GaAs/AlAs micropillar lasers with InGaAs quantum dots. The modulation of the emission wavelength takes place on the frequencies of the nanomechanical extensional and breathing (radial) modes of the micropillars. The amplitude of the modulation for various nanomechanical modes is different for every micropillar which is explained by a various elastic contact between the micropillar walls and polymer environment.}}, author = {{Czerniuk, T. and Tepper, J. and Akimov, A. V. and Unsleber, S. and Schneider, C. and Kamp, M. and Höfling, S. and Yakovlev, D. R. and Bayer, M.}}, issn = {{0003-6951}}, journal = {{Applied Physics Letters}}, number = {{4}}, publisher = {{AIP Publishing}}, title = {{{Impact of nanomechanical resonances on lasing from electrically pumped quantum dot micropillars}}}, doi = {{10.1063/1.4906611}}, volume = {{106}}, year = {{2015}}, } @article{6526, abstract = {{We introduce photon-statistics excitation spectroscopy and exemplarily apply it to a quantum-dot micropillar laser. Both the intensity and the photon number statistics of the emission from the micropillar show a strong dependence on the photon statistics of the light used for excitation of the sample. The results under coherent and pseudothermal excitation reveal that a description of the laser properties in terms of mean input photon numbers is not sufficient. It is demonstrated that the micropillar acts as a superthermal light source when operated close to its threshold. Possible applications for important spectroscopic techniques are discussed.}}, author = {{Kazimierczuk, T. and Schmutzler, J. and Aßmann, M. and Schneider, C. and Kamp, M. and Höfling, S. and Bayer, M.}}, issn = {{0031-9007}}, journal = {{Physical Review Letters}}, number = {{2}}, publisher = {{American Physical Society (APS)}}, title = {{{Photon-Statistics Excitation Spectroscopy of a Quantum-Dot Micropillar Laser}}}, doi = {{10.1103/physrevlett.115.027401}}, volume = {{115}}, year = {{2015}}, } @inproceedings{6529, author = {{Yakovlev, D. R. and Warkentin, W. and Brunne, D. and Mund, J. and Pavlov, V. V. and Rodina, A. V. and Pisarev, R. V. and Bayer, M.}}, booktitle = {{Nonlinear Optics and Applications IX}}, editor = {{Bertolotti, Mario and Haus, Joseph W. and Zheltikov, Alexei M.}}, location = {{Prague, Czech Rep}}, publisher = {{SPIE}}, title = {{{Novel mechanisms of optical harmonic generation on excitons in semiconductors}}}, doi = {{10.1117/12.2185309}}, year = {{2015}}, } @article{1696, author = {{Bader, Christina A. and Zeuner, Franziska and Bader, Manuel H. W. and Zentgraf, Thomas and Meier, Cedrik}}, issn = {{0021-8979}}, journal = {{Journal of Applied Physics}}, number = {{21}}, publisher = {{AIP Publishing}}, title = {{{Nonlinear optical sub-bandgap excitation of ZnO-based photonic resonators}}}, doi = {{10.1063/1.4936768}}, volume = {{118}}, year = {{2015}}, } @article{1698, author = {{Huang, Lingling and Mühlenbernd, Holger and Li, Xiaowei and Song, Xu and Bai, Benfeng and Wang, Yongtian and Zentgraf, Thomas}}, issn = {{0935-9648}}, journal = {{Advanced Materials}}, number = {{41}}, pages = {{6444--6449}}, publisher = {{Wiley-Blackwell}}, title = {{{Broadband Hybrid Holographic Multiplexing with Geometric Metasurfaces}}}, doi = {{10.1002/adma.201502541}}, volume = {{27}}, year = {{2015}}, } @article{1700, author = {{Zheng, Guoxing and Mühlenbernd, Holger and Kenney, Mitchell and Li, Guixin and Zentgraf, Thomas and Zhang, Shuang}}, issn = {{1748-3387}}, journal = {{Nature Nanotechnology}}, number = {{4}}, pages = {{308--312}}, publisher = {{Springer Nature}}, title = {{{Metasurface holograms reaching 80% efficiency}}}, doi = {{10.1038/nnano.2015.2}}, volume = {{10}}, year = {{2015}}, } @article{1461, author = {{Mühlenbernd, Holger and Georgi, Philip and Pholchai, Nitipat and Huang, Lingling and Li, Guixin and Zhang, Shuang and Zentgraf, Thomas}}, issn = {{2330-4022}}, journal = {{ACS Photonics}}, number = {{1}}, pages = {{124--129}}, publisher = {{American Chemical Society (ACS)}}, title = {{{Amplitude- and Phase-Controlled Surface Plasmon Polariton Excitation with Metasurfaces}}}, doi = {{10.1021/acsphotonics.5b00536}}, volume = {{3}}, year = {{2015}}, } @inproceedings{24290, abstract = {{The recent rapid development of silicon photonics technology has spurred the process of on-chip integration of all kinds of opto-electronic components. One of the most common components of such type is the opto-electrical receiver. The monolithic implementation of the receiver could potentially have lower power consumption, higher sensitivity and bandwidth due to very short diode to amplifier connection length, which has very low parasitic capacitance and series resistance. The SiGe photodiode itself is also very compact, thus lowering the junction capacitance and improving its bandwidth. Among the different optical communication systems, coherent transmission lately received a lot of attention due to the rising requirements of the optical link capacity, and it was shown that this particular approach could benefit greatly from the monolithic integration, since the major component required for the demodulation on the receiver side – 90° optical hybrid – could be implemented fully passive and directly on the same chip as the receiver itself, together with digital post-processing circuitry. Despite the initial complexity of the modulation scheme, advanced silicon photonics components like this optical hybrid could make coherent transmission attractive even for short-range optical links. I would like to present the actual designs, implementation and measurement results of 90° fully passive optical hybrids, implemented in the IHP SG25PIC (passive photonics IC) technology. One of the designs is based on 4x4 multimode interferometer (MMI). The other one is based on two separate 2x2 MMIs with additional delay element. The final designs didn’t require any additional tuning after fabrication and have shown sufficient precision and performance for a coherent system design. The results of this work were later used for the design of monolithic coherent receiver.}}, author = {{Gudyriev, Sergiy and Scheytt, Christoph}}, booktitle = {{Kleinheubacher Tagung 2015}}, pages = {{18}}, title = {{{Silicon photonics 90° optical hybrid design for coherent receivers}}}, year = {{2015}}, } @article{4332, abstract = {{LiTaO3 and LiNbO3 crystals are investigated here in a combined experimental and theoretical study that uses Raman spectroscopy in a complete set of scattering geometries and corresponding density-functional theory calculations to provide microscopic information on their vibrational properties. The Raman scattering efficiency is computed from first principles in order to univocally assign the measured Raman peaks to the calculated eigenvectors. Measured and calculated Raman spectra are shown to be in qualitative agreement and confirm the mode assignment by Margueron et al. [J. Appl. Phys. 111, 104105 (2012)], thus finally settling a long debate. While the two crystals show rather similar vibrational properties overall, the E-TO9 mode is markedly different in the two oxides. The deviations are explained by a different anion-cation bond type in LiTaO3 and LiNbO3 crystals.}}, author = {{Sanna, Simone and Neufeld, Sergej and Rüsing, Michael and Berth, Gerhard and Zrenner, Artur and Schmidt, Wolf Gero}}, issn = {{1098-0121}}, journal = {{Physical Review B}}, number = {{22}}, publisher = {{American Physical Society (APS)}}, title = {{{Raman scattering efficiency in LiTaO3 and LiNbO3 crystals}}}, doi = {{10.1103/physrevb.91.224302}}, volume = {{91}}, year = {{2015}}, } @article{39694, author = {{Zimmermann, Natalie and Jünnemann-Held, Gisela and Collings, Peter J. and Kitzerow, Heinz-Siegfried}}, issn = {{1744-683X}}, journal = {{Soft Matter}}, keywords = {{Condensed Matter Physics, General Chemistry}}, number = {{8}}, pages = {{1547--1553}}, publisher = {{Royal Society of Chemistry (RSC)}}, title = {{{Self-organized assemblies of colloidal particles obtained from an aligned chromonic liquid crystal dispersion}}}, doi = {{10.1039/c4sm02579b}}, volume = {{11}}, year = {{2015}}, } @article{39688, author = {{Urbanski, Martin and Mirzaei, Javad and Sharma, Anshul and Hofmann, Daniel and Kitzerow, Heinz-Siegfried and Hegmann, Torsten}}, issn = {{0267-8292}}, journal = {{Liquid Crystals}}, keywords = {{Condensed Matter Physics, General Materials Science, General Chemistry}}, number = {{2}}, pages = {{183--194}}, publisher = {{Informa UK Limited}}, title = {{{Chemically and thermally stable, emissive carbon dots as viable alternatives to semiconductor quantum dots for emissive nematic liquid crystal–nanoparticle mixtures with lower threshold voltage}}}, doi = {{10.1080/02678292.2015.1082651}}, volume = {{43}}, year = {{2015}}, } @article{39689, author = {{Wahle, Markus and Kitzerow, Heinz-Siegfried}}, issn = {{0003-6951}}, journal = {{Applied Physics Letters}}, keywords = {{Physics and Astronomy (miscellaneous)}}, number = {{20}}, publisher = {{AIP Publishing}}, title = {{{Electrically tunable zero dispersion wavelengths in photonic crystal fibers filled with a dual frequency addressable liquid crystal}}}, doi = {{10.1063/1.4936086}}, volume = {{107}}, year = {{2015}}, } @article{38086, author = {{Tiranov, Alexey and Lavoie, Jonathan and Ferrier, Alban and Goldner, Philippe and Verma, Varun B. and Nam, Sae Woo and Mirin, Richard P. and Lita, Adriana E. and Marsili, Francesco and Herrmann, Harald and Silberhorn, Christine and Gisin, Nicolas and Afzelius, Mikael and Bussières, Félix}}, issn = {{2334-2536}}, journal = {{Optica}}, keywords = {{Atomic and Molecular Physics, and Optics, Electronic, Optical and Magnetic Materials}}, number = {{4}}, publisher = {{The Optical Society}}, title = {{{Storage of hyperentanglement in a solid-state quantum memory}}}, doi = {{10.1364/optica.2.000279}}, volume = {{2}}, year = {{2015}}, } @article{13935, abstract = {{Recently, a new class of nonlinear systems was introduced, in which the self-trapping of fundamental and vortical localized modes in space of dimension D is supported by cubic self-repulsion with a strength growing as a function of the distance from the center, r, at any rate faster that rD. These systems support robust 2D and 3D modes which either do not exist or are unstable in other nonlinear systems. Here we demonstrate a possibility to create solitary vortices in this setting by applying a phase-imprinting torque to the ground state. Initially, a strong torque completely destroys the ground state. However, contrary to usual systems, where the destruction is irreversible, the present ones demonstrate a rapid restabilization and the creation of one or several shifted vortices orbiting the center. For the sake of comparison, we show analytically that, in the linear system with a 3D trapping potential, the action of a torque on the ground state is inefficient and creates only even-vorticity states with a small probability.}}, author = {{Driben, Rodislav and Meier, Torsten and Malomed, Boris A.}}, issn = {{2045-2322}}, journal = {{Scientific Reports}}, title = {{{Creation of vortices by torque in multidimensional media with inhomogeneous defocusing nonlinearity}}}, doi = {{10.1038/srep09420}}, volume = {{5}}, year = {{2015}}, } @article{22944, abstract = {{Recently, a new class of nonlinear systems was introduced, in which the self-trapping of fundamental and vortical localized modes in space of dimension D is supported by cubic self-repulsion with a strength growing as a function of the distance from the center, r, at any rate faster that rD. These systems support robust 2D and 3D modes which either do not exist or are unstable in other nonlinear systems. Here we demonstrate a possibility to create solitary vortices in this setting by applying a phase-imprinting torque to the ground state. Initially, a strong torque completely destroys the ground state. However, contrary to usual systems, where the destruction is irreversible, the present ones demonstrate a rapid restabilization and the creation of one or several shifted vortices orbiting the center. For the sake of comparison, we show analytically that, in the linear system with a 3D trapping potential, the action of a torque on the ground state is inefficient and creates only even-vorticity states with a small probability.}}, author = {{Driben, Rodislav and Meier, Torsten and Malomed, Boris A.}}, issn = {{2045-2322}}, journal = {{Scientific Reports}}, title = {{{Creation of vortices by torque in multidimensional media with inhomogeneous defocusing nonlinearity}}}, doi = {{10.1038/srep09420}}, volume = {{5}}, year = {{2015}}, } @article{13926, abstract = {{We predict a variety of composite quiescent and spinning two- and three-dimensional (2D and 3D) self-trapped modes in media with a repulsive nonlinearity whose local strength grows from center to periphery. These are 2D dipoles and quadrupoles, and 3D octupoles, as well as vortex–antivortex pairs and quadruplets. Unlike other multidimensional models, where such complex bound states either do not exist or are subject to strong instabilities, these modes are remarkably robust in the present setting. The results are obtained by means of numerical methods and analytically, using the Thomas–Fermi approximation. The predicted states may be realized in optical and matter-wave media with controllable cubic nonlinearities}}, author = {{Driben, Rodislav and Dror, Nir and Malomed, Boris A and Meier, Torsten}}, issn = {{1367-2630}}, journal = {{New Journal of Physics}}, title = {{{Multipoles and vortex multiplets in multidimensional media with inhomogeneous defocusing nonlinearity}}}, doi = {{10.1088/1367-2630/17/8/083043}}, volume = {{17}}, year = {{2015}}, } @article{13932, abstract = {{We predict a variety of composite quiescent and spinning two- and three-dimensional (2D and 3D) self-trapped modes in media with a repulsive nonlinearity whose local strength grows from center to periphery. These are 2D dipoles and quadrupoles, and 3D octupoles, as well as vortex–antivortex pairs and quadruplets. Unlike other multidimensional models, where such complex bound states either do not exist or are subject to strong instabilities, these modes are remarkably robust in the present setting. The results are obtained by means of numerical methods and analytically, using the Thomas–Fermi approximation. The predicted states may be realized in optical and matter-wave media with controllable cubic nonlinearities}}, author = {{Driben, Rodislav and Dror, Nir and Malomed, Boris A and Meier, Torsten}}, issn = {{1367-2630}}, journal = {{New Journal of Physics}}, title = {{{Multipoles and vortex multiplets in multidimensional media with inhomogeneous defocusing nonlinearity}}}, doi = {{10.1088/1367-2630/17/8/083043}}, volume = {{17}}, year = {{2015}}, } @article{22948, abstract = {{We predict a variety of composite quiescent and spinning two- and three-dimensional (2D and 3D) self-trapped modes in media with a repulsive nonlinearity whose local strength grows from center to periphery. These are 2D dipoles and quadrupoles, and 3D octupoles, as well as vortex–antivortex pairs and quadruplets. Unlike other multidimensional models, where such complex bound states either do not exist or are subject to strong instabilities, these modes are remarkably robust in the present setting. The results are obtained by means of numerical methods and analytically, using the Thomas–Fermi approximation. The predicted states may be realized in optical and matter-wave media with controllable cubic nonlinearities}}, author = {{Driben, Rodislav and Dror, Nir and Malomed, Boris A. and Meier, Torsten}}, issn = {{1367-2630}}, journal = {{New Journal of Physics}}, title = {{{Multipoles and vortex multiplets in multidimensional media with inhomogeneous defocusing nonlinearity}}}, doi = {{10.1088/1367-2630/17/8/083043}}, volume = {{17}}, year = {{2015}}, } @inproceedings{13927, author = {{Lange, C. and Schubert, O. and Hohenleutner, M. and Langer, F. and Baierl, S. and Maag, T. and Urbanek, B. and Edwards, E. R. J. and Woltersdorf, G. and Bougeard, D. and Huttner, U. and Golde, D. and Meier, Torsten and Kira, M. and Koch, S. W. and Huber, R.}}, booktitle = {{Nonlinear Frequency Generation and Conversion: Materials, Devices, and Applications XIV}}, editor = {{Vodopyanov, Konstantin L.}}, publisher = {{SPIE}}, title = {{{Sub-cycle control of multi-THz high-harmonic generation and all-coherent charge transport in bulk semiconductors}}}, doi = {{10.1117/12.2085101}}, volume = {{9347}}, year = {{2015}}, }