@inproceedings{3967, abstract = {{We simulate the linear and nonlinear optical response from split-ring resonator (SRR) arrays to study collective effects between the constituent SRRs that determine spectral properties of the second harmonic generation (SHG). We apply the Discontinuous Galerkin Time Domain (DGTD) method and the hydrodynamic Maxwell-Vlasov model to calculate the SHG emission. Our model is able to qualitatively reproduce and explain the non-monotonic dependence of the spectral SHG transmission measured experimentally for SRR arrays with different lattice constants}}, author = {{Grynko, Yevgen and Meier, Torsten and Linden, Stefan and Niesler, Fabian B. P. and Wegener, Martin and Förstner, Jens}}, keywords = {{tet_topic_meta, tet_topic_shg}}, location = {{Bad Honnef}}, number = {{1}}, pages = {{128--130}}, publisher = {{AIP Conference Proceedings}}, title = {{{Near-field coupling and second-harmonic generation in split-ring resonator arrays}}}, doi = {{10.1063/1.4750118}}, volume = {{1475}}, year = {{2012}}, } @article{3970, abstract = {{Optical experiments on second-harmonic generation from split-ring-resonator square arrays show a nonmonotonic dependence of the conversion efficiency on the lattice constant. This finding is interpreted in terms of a competition between dilution effects and linewidth or near-field changes due to interactions among the individual elements in the array.}}, author = {{Linden, S. and Niesler, F. B. P. and Förstner, Jens and Grynko, Yevgen and Meier, Torsten and Wegener, M.}}, issn = {{0031-9007}}, journal = {{Physical Review Letters}}, keywords = {{tet_topic_shg, tet_topic_meta}}, number = {{1}}, publisher = {{American Physical Society (APS)}}, title = {{{Collective Effects in Second-Harmonic Generation from Split-Ring-Resonator Arrays}}}, doi = {{10.1103/physrevlett.109.015502}}, volume = {{109}}, year = {{2012}}, } @misc{4171, abstract = {{The method involves exciting a quantum system with photons in a polarization state. Two states of the quantum system are excited with linear horizontal and vertical polarizations that are orthogonal to each other, where the states exhibit an energetic gap smaller than energetic bandwidth of photons. The states are assigned based on the polarizations, where the quantum system is arranged in a superposition state. The quantum system is formed by a quantum bit that is formed as a two-level system.}}, author = {{Förstner, Jens and Mantei, D. and de Vasconcellos, S. Michaelis and Zrenner, Artur}}, keywords = {{tet_topic_qd}}, title = {{{Method for transmission of information about polarization state of photons to stationary system}}}, year = {{2011}}, } @inproceedings{4312, abstract = {{The intensity dependence of optically-induced injection currents in semiconductor quantum wells is investigated numerically. Oscillatory behavior of the electron charge current transients as function of intensity and time is predicted and explained.}}, author = {{Pochwala, Michal and Duc, Huynh Thanh and Förstner, Jens and Meier, Torsten}}, booktitle = {{CLEO:2011 - Laser Applications to Photonic Applications}}, isbn = {{9781557529107}}, issn = {{2160-8989 }}, keywords = {{tet_topic_qw}}, location = {{Baltimore, Maryland (USA)}}, publisher = {{Optical Society of America}}, title = {{{Intensity dependence of optically-induced injection currents in semiconductor quantum wells}}}, doi = {{10.1364/qels.2011.qmk4}}, year = {{2011}}, } @inproceedings{4043, abstract = {{We present numerical results of the mutual coupling between photonic crystal cavities and semiconductor quantum dots. Normal mode splitting between a single cavity mode and a single quantum dot is shown under weak excitation, while under strong excitation Q‐factor dependent side bands appear, according to the AC‐Stark effect. Coupled photonic crystals, aligned parallel but displaced under a 30°‐angle for efficient coupling, show line splittings of all eigenmodes, if a single eigenmode is resonantly coupled to a single quantum dot. The mutual coupling of N resonant quantum dots to a single cavity mode results in a N−−√ scaling of the splitting, known from quantum optics, but corrected by the field amplitude fraction for not collocated quantum dots.}}, author = {{Declair, S. and Song, X. and Meier, Torsten and Förstner, Jens}}, booktitle = {{THE FOURTH INTERNATIONAL WORKSHOP 2011}}, keywords = {{tet_topic_phc, tet_topic_qd}}, location = {{Bad Honnef}}, number = {{123}}, pages = {{123--125}}, publisher = {{AIP}}, title = {{{Simulation of Mutual Coupling of Photonic Crystal Cavity Modes and Semiconductor Quantum Dots}}}, doi = {{10.1063/1.3644232}}, volume = {{1398}}, year = {{2011}}, } @inproceedings{4048, abstract = {{We present an ab-initio method for calculating nonlinear and nonlocal optical effects in metallic slabs with sub-wavelength thickness. We find a strong localization of the second-harmonic current at the metal-vacuum interface.}}, author = {{Wand, Mathias and Schindlmayr, Arno and Meier, Torsten and Förstner, Jens}}, booktitle = {{CLEO:2011 - Laser Applications to Photonic Applications }}, isbn = {{978-1-4577-1223-4}}, issn = {{2160-8989}}, keywords = {{tet_topic_shg}}, location = {{Baltimore, Maryland, United States}}, publisher = {{Optical Society of America}}, title = {{{Theoretical approach to the ultrafast nonlinear optical response of metal slabs}}}, doi = {{10.1364/CLEO_AT.2011.JTuI59}}, year = {{2011}}, } @inproceedings{2194, author = {{Meyer, Björn and Plessl, Christian and Förstner, Jens}}, booktitle = {{Symp. on Application Accelerators in High Performance Computing (SAAHPC)}}, keywords = {{tet_topic_hpc}}, pages = {{60--63}}, publisher = {{IEEE Computer Society}}, title = {{{Transformation of scientific algorithms to parallel computing code: subdomain support in a MPI-multi-GPU backend}}}, doi = {{10.1109/SAAHPC.2011.12}}, year = {{2011}}, } @inproceedings{4042, abstract = {{A simulation environment for metallic nanostructures based on the Discontinuous Galerkin Time Domain method is presented. It is used to model optical transmission by silver bi‐chiral plasmonic crystals. The results of simulations qualitatively and quantitavely agree with experimental measurements of transmitted circular polarization.}}, author = {{Grynko, Yevgen and Förstner, Jens and Meier, Torsten and Radke, André and Gissibl, Timo and Braun, Paul V. and Giessen, Harald}}, editor = {{Chigrin, Dmitry N.}}, keywords = {{tet_topic_meta}}, number = {{1}}, pages = {{76--78}}, publisher = {{AIP}}, title = {{{Application of the Discontinuous Galerkin Time Domain Method to the Optics of Bi-Chiral Plasmonic Crystals}}}, doi = {{10.1063/1.3644217}}, volume = {{1398}}, year = {{2011}}, } @article{4089, abstract = {{We study the influence of the phonon environment on the electron dynamics in a doped quantum dot molecule. A non-perturbative quantumkinetic theory based on correlation expansion is used in order to describe both diagonal and off-diagonal electron-phonon couplings representing real and virtual processes with relevant acoustic phonons. We show that the relaxation is dominated by phononassisted electron tunneling between constituent quantum dots and occurs on a picosecond time scale. The dependence of the time evolution of the quantum dot occupation probabilities on the energy mismatch between the quantum dots is studied in detail.}}, author = {{Grodecka-Grad, Anna and Förstner, Jens}}, issn = {{1862-6351}}, journal = {{physica status solidi (c)}}, keywords = {{tet_topic_qd}}, number = {{4}}, pages = {{1125--1128}}, publisher = {{Wiley}}, title = {{{Phonon-assisted decoherence and tunneling in quantum dot molecules}}}, doi = {{10.1002/pssc.201000824}}, volume = {{8}}, year = {{2011}}, } @article{4120, abstract = {{The intensity dependence of optically-induced injection currents in unbiased GaAs semiconductor quantum wells grown in [110] direction is investigated theoretically for a number of well widths. Our microscopic analysis is based on a 14 x 14 band k . p method in combination with the multisubband semiconductor Bloch equations. An oscillatory dependence of the injection current transients as function of intensity and time is predicted and explained. It is demonstrated that optical excitations involving different subbands and Rabi flopping are responsible for this complex dynamics.}}, author = {{Pochwała, Michał and Duc, Huynh Thanh and Förstner, Jens and Meier, Torsten}}, issn = {{1862-6254}}, journal = {{physica status solidi (RRL) - Rapid Research Letters}}, keywords = {{tet_topic_qw}}, number = {{3}}, pages = {{119--121}}, publisher = {{Wiley}}, title = {{{Intensity-dependent ultrafast dynamics of injection currents in unbiased GaAs quantum wells}}}, doi = {{10.1002/pssr.201004529}}, volume = {{5}}, year = {{2011}}, } @article{4049, abstract = {{The injection of photocurrents by femtosecond laser pulses in (110)-orientedGaAs/AlGaAs quantum wells is investigated theoretically and experimentally. The roomtemperature measurements show an oscillatory dependence of the injection current amplitude and direction on the excitation photon energy. Microscopic calculations using the semiconductor Bloch equations that are set up on the basis of k.p band structure calculations provide a detailed understanding of the experimental findings.}}, author = {{Thanh Duc, Huynh and Förstner, Jens and Meier, Torsten and Priyadarshi, Shekhar and Racu, Ana Maria and Pierz, Klaus and Siegner, Uwe and Bieler, Mark}}, issn = {{1862-6351}}, journal = {{physica status solidi (c)}}, keywords = {{tet_topic_qw}}, number = {{4}}, pages = {{1137--1140}}, publisher = {{Wiley}}, title = {{{Oscillatory excitation energy dependence of injection currents in GaAs/AlGaAs quantum wells}}}, doi = {{10.1002/pssc.201000831}}, volume = {{8}}, year = {{2011}}, } @article{4118, abstract = {{We numerically investigate the coupling between circular resonators and study strong light‐matter coupling of single as well as multiple circular resonators to quantum‐mechanical resonators in two dimensional model simulations. For all cases, the computed resonances of the coupled system as function of the detuning show anti‐crossings. The obtained mode splittings of coupled optical resonators are strongly depending on distance and cluster in almost degenerate eigenstates for large distances, as is known from coupled resonator optical waveguides. Vacuum Rabi splitting is observed for a quantum dot strongly coupled to eigenmodes of single perfectly cylindrical resonators. }}, author = {{Declair, S. and Meier, Torsten and Förstner, Jens}}, issn = {{1862-6351}}, journal = {{physica status solidi (c)}}, keywords = {{tet_topic_phc, tet_topic_microdisk}}, number = {{4}}, pages = {{1254--1257}}, publisher = {{Wiley}}, title = {{{Numerical investigation of the coupling between microdisk modes and quantum dots}}}, doi = {{10.1002/pssc.201000869}}, volume = {{8}}, year = {{2011}}, } @article{4040, abstract = {{We numerically investigate the interaction dynamics of coupled cavities in planar photonic crystal slabs in different configurations. The single cavity is optimized for a long lifetime of the fundamental mode, reaching a Q-factor of ≈43, 000 using the method of gentle confinement. For pairs of cavities we consider several configurations and present a setup with strongest coupling observable as a line splitting of about 30 nm. Based on this configuration, setups with three cavities are investigated.}}, author = {{Declair, S. and Meier, Torsten and Zrenner, Artur and Förstner, Jens}}, issn = {{1569-4410}}, journal = {{Photonics and Nanostructures - Fundamentals and Applications}}, keywords = {{tet_topic_phc}}, number = {{4}}, pages = {{345--350}}, publisher = {{Elsevier BV}}, title = {{{Numerical analysis of coupled photonic crystal cavities}}}, doi = {{10.1016/j.photonics.2011.04.012}}, volume = {{9}}, year = {{2011}}, } @article{4044, abstract = {{A simulation environment for metallic nanostructures based on the Discontinuous Galerkin Time Domain method is presented. The model is used to compute the linear and nonlinear optical response of split ring resonators and to study physical mechanisms that contribute to second harmonic generation.}}, author = {{Grynko, Yevgen and Förstner, Jens and Meier, Torsten}}, issn = {{1825-1242}}, journal = {{AAPP | Atti della Accademia Peloritana dei Pericolanti}}, keywords = {{tet_topic_numerics, tet_topic_shg, tet_topic_meta}}, number = {{1}}, title = {{{Application of the discontinous Galerkin time domain method to the optics of metallic nanostructures}}}, doi = {{10.1478/C1V89S1P041}}, volume = {{89}}, year = {{2011}}, } @article{4091, abstract = {{We present a nonequilibrium ab initio method for calculating nonlinear and nonlocal optical effects in metallic slabs with a thickness of several nanometers. The numerical analysis is based on the full solution of the time‐dependent Kohn–Sham equations for a jellium system and allows to study the optical response of metal electrons subject to arbitrarily shaped intense light pulses. We find a strong localization of the generated second‐harmonic current in the surface regions of the slabs. }}, author = {{Wand, Mathias and Schindlmayr, Arno and Meier, Torsten and Förstner, Jens}}, issn = {{1521-3951}}, journal = {{Physica Status Solidi B}}, keywords = {{tet_topic_shg}}, number = {{4}}, pages = {{887--891}}, publisher = {{Wiley-VCH}}, title = {{{Simulation of the ultrafast nonlinear optical response of metal slabs}}}, doi = {{10.1002/pssb.201001219}}, volume = {{248}}, year = {{2011}}, } @inproceedings{4122, abstract = {{We experimentally and theoretically investigate injection currents generated by femtosecond single-color circularly-polarized laser pulses in (110)-oriented GaAs quantum wells. The current measurements are performed by detecting the emitted Terahertz radiation at room temperature. The microscopic theory is based on a 14 x 14 k • p band-structure calculation in combination with the multi-subband semiconductor Bloch equations. For symmetric GaAs quantum wells grown in (110) direction, an oscillatory dependence of the injection currents on the exciting photon energy is obtained. The results of the microscopic theory are in good agreement with the measurements. }}, author = {{Duc, H. T. and Pochwala, M. and Förstner, Jens and Meier, Torsten and Priyadarshi, S. and Racu, A. M. and Pierz, K. and Siegner, U. and Bieler, M.}}, booktitle = {{Ultrafast Phenomena in Semiconductors and Nanostructure Materials XV}}, editor = {{Tsen, Kong-Thon and Song, Jin-Joo and Betz, Markus and Elezzabi, Abdulhakem Y.}}, keywords = {{tet_topic_qw}}, publisher = {{SPIE}}, title = {{{Injection currents in (110)-oriented GaAs/AlGaAs quantum wells: recent progress in theory and experiment}}}, doi = {{10.1117/12.876972}}, volume = {{7937}}, year = {{2011}}, } @article{4046, abstract = {{We demonstrate by spin quantum beat spectroscopy that in undoped symmetric (110)-oriented GaAs/AlGaAs single quantum wells, even a symmetric spatial envelope wave function gives rise to an asymmetric in-plane electron Land´e g-factor. The anisotropy is neither a direct consequence of the asymmetric in-plane Dresselhaus splitting nor a direct consequence of the asymmetric Zeeman splitting of the hole bands, but rather it is a pure higher-order effect that exists as well for diamond-type lattices. The measurements for various well widths are very well described within 14 × 14 band k·p theory and illustrate that the electron spin is an excellent meter variable for mapping out the internal—otherwise hidden—symmetries in two-dimensional systems. Fourth-order perturbation theory yields an analytical expression for the strength of the g-factor anisotropy, providing a qualitative understanding of the observed effects.}}, author = {{Hübner, J. and Kunz, S. and Oertel, S. and Schuh, D. and Pochwała, M. and Duc, H. T. and Förstner, Jens and Meier, Torsten and Oestreich, M.}}, issn = {{1098-0121}}, journal = {{Physical Review B}}, keywords = {{tet_topic_qw}}, number = {{4}}, pages = {{041301(R)}}, publisher = {{American Physical Society (APS)}}, title = {{{Electron g-factor anisotropy in symmetric (110)-oriented GaAs quantum wells}}}, doi = {{10.1103/physrevb.84.041301}}, volume = {{84}}, year = {{2011}}, } @article{4129, abstract = {{We study a single quantum dot molecule doped with one electron in the presence of electron-phonon coupling. Both diagonal and off-diagonal interactions representing real and virtual processes with acoustic phonons via deformation potential and piezoelectric coupling are taken into account. We employ a non-perturbative quantum kinetic theory and show that the phonon-mediated relaxation is dominated by an electron tunneling on a picosecond time scale.A dependence of the relaxation on the temperature and the strength of the tunneling coupling is analyzed.}}, author = {{Grodecka-Grad, Anna and Förstner, Jens}}, issn = {{1742-6596}}, journal = {{Journal of Physics: Conference Series}}, keywords = {{tet_topic_qd}}, publisher = {{IOP Publishing}}, title = {{{Phonon-mediated relaxation in doped quantum dot molecules}}}, doi = {{10.1088/1742-6596/245/1/012035}}, volume = {{245}}, year = {{2010}}, } @article{4174, abstract = {{A quantum dot molecule doped with a single electron in the presence of diagonal and off-diagonal carrierphonon couplings is studied by means of a nonperturbative quantum kinetic theory. The interaction with acoustic phonons by deformation potential and piezoelectric coupling is taken into account. We show that the phonon-mediated relaxation is fast on a picosecond time scale and is dominated by the usually neglected off-diagonal coupling to the lattice degrees of freedom leading to phonon-assisted electron tunneling. We show that in the parameter regime of current electrical and optical experiments, the microscopic non-Markovian theory has to be employed.}}, author = {{Grodecka-Grad, A. and Förstner, Jens}}, issn = {{1098-0121}}, journal = {{Physical Review B}}, keywords = {{tet_topic_qd}}, number = {{11}}, publisher = {{American Physical Society (APS)}}, title = {{{Theory of phonon-mediated relaxation in doped quantum dot molecules}}}, doi = {{10.1103/physrevb.81.115305}}, volume = {{81}}, year = {{2010}}, } @article{4127, abstract = {{The dynamics of charge and spin injection currents excited by circularly polarized, one-color laser beams in semiconductor quantum wells is analyzed. Our microscopic approach is based on a 14x14 k · p band-structure theory in combination with multisubband semiconductor Bloch equations which allows a detailed analysis of the photogenerated carrier distributions and coherences in k space. Charge and spin injection currents are numerically calculated for [110]- and [001]-grown GaAs quantum wells including dc population contributions and ac contributions that arise from intersubband coherences. The dependencies of the injection currents on the excitation conditions, in particular, the photon energy are computed and discussed.}}, author = {{Duc, Huynh Thanh and Förstner, Jens and Meier, Torsten}}, issn = {{1098-0121}}, journal = {{Physical Review B}}, keywords = {{tet_topic_qw}}, number = {{11}}, publisher = {{American Physical Society (APS)}}, title = {{{Microscopic analysis of charge and spin photocurrents injected by circularly polarized one-color laser pulses in GaAs quantum wells}}}, doi = {{10.1103/physrevb.82.115316}}, volume = {{82}}, year = {{2010}}, }