@inproceedings{43265, abstract = {{The dynamics of charge and spin currents generated by two-color femtosecond laser pulses is investigated. Non-Markovian memory effects lead to oscillations in the coherent transients. Consequences arising from the heavy-hole light-hole coupling are predicted.}}, author = {{Meier, Torsten and Vu, Q.T. and Duc, H.T. and Pasenow, B. and Haug, H. and Koch, S.W.}}, booktitle = {{International Conference on Ultrafast Phenomena XV}}, isbn = {{1-55752-810-1}}, location = {{Pacific Grove, California United States}}, publisher = {{Optical Society of America}}, title = {{{Microscopic Many-Body Analysis of Ultrafast Photocurrents in Semiconductor Nanostructures}}}, doi = {{10.1364/UP.2006.TuD8}}, volume = {{88}}, year = {{2006}}, } @article{23491, abstract = {{A brief overview of a consistent microscopic approach to model the optical and electronic properties of semiconductor nanostructures is presented. Coupled semiconductor Bloch and Maxwell equations are used to investigate the performance of semiconductor microcavity structures, photonic band gap systems, and lasers. The predictive potential of the microscopic theory is demonstrated for several examples of practical importance. Optical gain and output characteristics are computed for modern vertical external cavity surface emitting laser structures. It is shown how design flexibilities can be used to optimize the device performance. Nanostructures are proposed where semiconductor quantum wells are embedded in one-dimensional photonic crystals. For field modes spectrally below the photonic band edge it is shown that the optical gain and absorption can be enhanced by more than one order of magnitude over the value of the homogeneous medium. The increased gain can be used for laser action by placing quantum wells and a suitably designed photonic crystal structure inside a microcavity.}}, author = {{Thränhardt, A. and Meier, Torsten and Reichelt, Matthias and Schlichenmaier, C. and Pasenow, B. and Kuznetsova, I. and Becker, S. and Stroucken, T. and Hader, J. and Zakharian, A.R. and Moloney, J.V. and Chow, W.W. and Koch, S.W.}}, issn = {{0022-3093}}, journal = {{Journal of Non-Crystalline Solids}}, number = {{23-25}}, pages = {{2480--2483}}, title = {{{Microscopic modeling of the optical properties of semiconductor nanostructures}}}, doi = {{10.1016/j.jnoncrysol.2006.02.064}}, volume = {{352}}, year = {{2006}}, } @article{23492, abstract = {{The coherent ultrafast optical injection and the temporal evolution of charge and spin currents in semiconductors is analyzed using a microscopic many-body theory. The approach is based on the semiconductor Bloch equations and includes light-field-induced intraband and interband excitations, excitonic effects, and carrier–LO-phonon and carrier-carrier scattering processes. The relaxation effects are treated both in the second Born-Markov approximation and on the level of quantum kinetic theory including memory effects. The dynamics of the charge and spin currents is evaluated numerically for a one-dimensional model system. The dependence of the currents and their decay on the temperature, the excitation intensities, and the frequencies of the incident light fields is discussed. Whereas the overall decay dynamics is described well within the Markov approximation, the quantum kinetic theory predicts additional oscillatory signatures in the current transients.}}, author = {{Duc, H. T. and Vu, Q. T. and Meier, Torsten and Haug, H. and Koch, S. W.}}, issn = {{1098-0121}}, journal = {{Physical Review B}}, number = {{16}}, title = {{{Temporal decay of coherently optically injected charge and spin currents due to carrier–LO-phonon and carrier-carrier scattering}}}, doi = {{10.1103/physrevb.74.165328}}, volume = {{74}}, year = {{2006}}, } @inbook{44120, author = {{Meier, Torsten and Koch, S.W.}}, booktitle = {{Photonic Crystals: Advances in Design, Fabrication, and Characterization}}, editor = {{Busch, Kurt and Lölkes, Stefan and Wehrspohn, Ralf B. and Föll, Helmut}}, pages = {{43--62}}, publisher = {{John Wiley & Sons}}, title = {{{Semiconductor Optics in Photonic Crystal Structures}}}, year = {{2006}}, } @inbook{43270, abstract = {{The linear and nonlinear optical properties of semiconductors are strongly influenced by the Coulomb interaction among the photoexcited carriers. Within the framework of the semiconductor Bloch equations such many-body effects can be described on the basis of a microscopic theory. In this article, we briefly review our recent contributions to two specific topics. First, the coherent optical generation of charge and spin currents and their subsequent decay via scattering processes is discussed. As a second example, the spatially-inhomogeneous optical properties of hybrid structures which consist of photonic crystals and semiconductor nanostructures are described. Many of the numerical results have been obtained using massively parallel computer programs which were run on the IBM p690-Cluster Jump in Jülich.}}, author = {{Meier, Torsten and Duc, Huynh Thanh and Reichelt, Matthias and Pasenow, B. and Stroucken, T. and Koch, S.W.}}, booktitle = {{Germany in NIC Series Vol. 32}}, editor = {{Munster, G. and Wolf, D. and Kremer, M.}}, isbn = {{3-00-017351-X}}, pages = {{219--226}}, publisher = {{John von Neumann Institute for Computing}}, title = {{{Computational Optoelectronics of Semiconductor Nanostructures including Many-Body Effects}}}, year = {{2006}}, } @inproceedings{44294, abstract = {{The band alignment of GaNAs in heterostructures is determined by investigating the energetically lowest optical band-to-band transition of In0.23Ga0.77As/GaNyAs1−y samples with varying y. In a type II alignment this transition is between states located in different layers. Photoreflectance, photoluminescence, and the radiative decay of excited carrier densities are both measured and microscopically modeled. The bandstructure for every sample is computed. Based on this bandstructure all optical properties and the radiative decay are computed using the semiconductor Bloch [1] and luminescence [2] equations including electron-electron and electron-phonon interaction on scattering level. Thus the modeling is consistent and without free parameters. Overall good agreement between theory and experiment is achieved and used to explain all experimental features and to determine the band alignment}}, author = {{Meier, Torsten and Schlichenmaier, C. and Thraenhardt, Angela and Koch, S.W. and Hantke, Kristian and Ruehle, Wolfgang and Gruening, Heiko and Klar, Peter J. and Heimbrodt, Wolfgang and Hader, J. and Moloney, Jerome V.}}, booktitle = {{Meeting of the German Physical Society, Solid-State Physics Section, and the European Physical Society Condensed Matter Division}}, location = {{ Dresden, Germany}}, title = {{{Type I type II transition in optical spectra-experiments and microscopic theory}}}, volume = {{41}}, year = {{2006}}, } @inproceedings{44296, abstract = {{Extreme nonlinear optics denotes the regime where the Rabi frequency is comparable to or even larger than the band gap frequency. This regime can be reached experimentally by using intense ultrashort laser pulses which have a duration of just a few femtoseconds, see, e.g., [1]. As shown in [2] for the case of a two-level system, a theoretical analysis of extreme nonlinear optics requires one to describe the dynamics on ultrashort time scales beyond the rotating-wave approximation. Such calculations describe, e.g., the generation of higher harmonics and Mollow tripletts [1,2]. Here, we use a microscopic model of a two-band semiconductor with Coulomb interaction to analyze the regime of extreme nonlinear optics. It is, in particular, shown that the importance of excitonic effects which are known to dominate the nonlinear optical response at moderate excitation intensities become less important at largely elevated intensities}}, author = {{Meier, Torsten and Golde, Daniel and Koch, S.W.}}, booktitle = {{Meeting of the German Physical Society, Solid-State Physics Section, and the European Physical Society Condensed Matter Division}}, location = {{Dresden, Germany}}, title = {{{Microscopic analysis of extreme nonlinear optics in semiconductors}}}, volume = {{41}}, year = {{2006}}, } @inproceedings{44293, author = {{Meier, Torsten and Vu, Q.T. and Koch, S.W. and Duc, Huynh Thanh}}, booktitle = {{Meeting of the German Physical Society, Solid-State Physics Section, and the European Physical Society Condensed Matter Division}}, issn = {{0420-0195}}, location = {{Dresden, Germany}}, title = {{{Coherent optical generation and decay of charge and spin currents in semiconductor heterostructures analyzed by microscopic theory}}}, volume = {{41}}, year = {{2006}}, } @inproceedings{44295, author = {{Meier, Torsten and Bozsoki, Peter and Hoyer, W. and Kira, M. and Thomas, P. and Koch, S.W. and Maschke, K.}}, booktitle = {{Meeting of the German Physical Society, Solid-State Physics Section, and the European Physical Society Condensed Matter Division}}, location = {{Dresden, Germany}}, title = {{{Extracting the Random potential of disordered semiconductors via directional interference of photoluminescence}}}, volume = {{41}}, year = {{2006}}, } @inproceedings{4191, abstract = {{We study optical second-harmonic generation from planar arrays of magnetic split-ring resonators at 1.5 microns resonance wavelength. We obtain by far the largest signals when exciting the magnetic-dipole resonance. }}, author = {{Klein, Matthias W. and Enkrich, Christian and Wegener, Martin and Förstner, Jens and Moloney, Jerome V. and Hoyer, Walter and Stroucken, Tineke and Meier, Torsten and Koch, Stephan W. and Linden, Stefan}}, booktitle = {{Photonic Metamaterials: From Random to Periodic}}, isbn = {{155752808X}}, keywords = {{tet_topic_meta}}, publisher = {{OSA}}, title = {{{Optical Experiments on Second-Harmonic Generation with Metamaterials Composed of Split-Ring Resonators}}}, doi = {{10.1364/meta.2006.tuc5}}, year = {{2006}}, } @article{43272, abstract = {{Optical interband transitions in a series of In0.23Ga0.77As–GaN𝑥As1−𝑥 quantum well samples are investigated. For changing nitrogen content, a type I-type II transition is identified by a detailed analysis of photoluminescence and photoreflectance spectra. Experimental results are compared systematically with spectra calculated by a microscopic theory. A valence band offset parameter of (1.5±0.5)eV is extracted for this heterostructure system.This work was supported by the Deutsche Forschungsgemeinschaft (Research Group on Metastable Compound Semiconductors and Heterostructures), by AFOSR (F49620-02-1-0380) and the Max-Planck Research Prize of the Max-Planck Society and Humboldt Foundation. We thank Stanko Tomić (Daresbury Laboratory) for fruitful discussions. }}, author = {{Schlichenmaier, C. and Grüning, H. and Thränhardt, A. and Klar, P.J. and Kunert, B. and Volz, K. and Stolz, W. and Heimbrodt, W. and Meier, Torsten and Koch, S.W.}}, journal = {{Applied Physics Letters}}, number = {{8}}, publisher = {{American Institute of Physics}}, title = {{{Type I-type II transition in InGaAs–GaNAs heterostructures}}}, doi = {{American Institute of Physics}}, volume = {{86}}, year = {{2005}}, } @article{43271, abstract = {{The optical and electronic properties of semiconductor heterostructures in the vicinity of photonic crystals are discussed. The theoretical approach provides a self-consistent solution of the dynamics of the electromagnetic field and the material excitations. Due to the influence of the structured dielectric environment on the Coulomb interaction, the exciton resonances and the quasiequilibrium carrier densities in the spatially homogeneous semiconductor become space dependent. It is demonstrated that these inhomogeneities lead to distinct modifications of the optical absorption and gain spectra. As an application, numerically calculated density-dependent optical spectra are analyzed for an array of semiconductor quantum wires which are close to a two-dimensional photonic crystal. The spatial inhomogeneities result in novel excitonic absorption features and modification of the optical gain in these structures.}}, author = {{Reichelt, Matthias and Pasenow, B. and Meier, Torsten and Stroucken, T. and Koch, S.W.}}, journal = {{Physical Review B}}, number = {{3}}, publisher = {{035346}}, title = {{{ Spatially inhomogeneous optical gain in semiconductor photonic-crystal structures}}}, doi = {{10.1103/PhysRevB.71.035346}}, volume = {{71}}, year = {{2005}}, } @article{23506, abstract = {{The optical properties of semiconductor quantum wells embedded in one-dimensional photonic crystal structures are analyzed by a self-consistent solution of Maxwell’s equations and a microscopic many-body theory of the material excitations. For a field mode spectrally below the photonic band edge it is shown that the optical absorption and gain are enhanced, exceeding by more than 1 order of magnitude the values of a homogeneous medium. For the photonic crystal structure inside a microcavity the gain increases superlinearly with the number of wells and for more than five wells exceeds the gain of a corresponding vertical-cavity surface-emitting laser.}}, author = {{Pasenow, Bernhard and Reichelt, Matthias and Stroucken, Tineke and Meier, Torsten and Koch, Stephan W. and Zakharian, Aramis R. and Moloney, Jerome V.}}, issn = {{0740-3224}}, journal = {{Journal of the Optical Society of America B}}, number = {{9}}, pages = {{2039--2048}}, title = {{{Enhanced light-matter interaction in semiconductor heterostructures embedded in one-dimensional photonic crystals}}}, doi = {{10.1364/josab.22.002039}}, volume = {{22}}, year = {{2005}}, } @article{23502, abstract = {{Significant aspects of the light–matter interaction can be strongly modified in suitably designed systems consisting of semiconductor nanostructures and dielectric photonic crystals. To analyze such effects, a microscopic theory is presented, which is capable of describing the optoelectronic properties of such hybrid systems via a self-consistent solution of the dynamics of the optical field and the photoexcitations of the material. The theory is applied to investigate the local excitonic resonances, which arise as a consequence of the modified Coulomb interaction in the vicinity of a structured dielectric medium. The excitation of a coherent superposition of the spatially inhomogeneous optical transitions induces an intricate wave packet dynamics. In the presence of dephasing and relaxation processes, the coherent oscillations are damped and the photoexcited carriers relax into spatially inhomogeneous quasi-equilibrium distributions.}}, author = {{Pasenow, B. and Reichelt, Matthias and Stroucken, T. and Meier, Torsten and Koch, S. W.}}, issn = {{1098-0121}}, journal = {{Physical Review B}}, number = {{19}}, pages = {{195321}}, title = {{{Excitonic wave packet dynamics in semiconductor photonic-crystal structures}}}, doi = {{10.1103/physrevb.71.195321}}, volume = {{71}}, year = {{2005}}, } @article{23504, abstract = {{The coherent optical injection and temporal decay of spin and charge currents in semiconductor heterostructures is described microscopically, including excitonic effects, many-body Coulomb correlations, and the carrier LO-phonon coupling on the second-order Born-Markov level, as well as nonperturbative light-field-induced intraband and interband excitations. A nonmonotonic dependence of the currents on the intensities of the laser beams is predicted. Enhanced damping of the spin current relative to the charge current is obtained as a consequence of Coulomb scattering.}}, author = {{Duc, Huynh Thanh and Meier, Torsten and Koch, S. W.}}, issn = {{0031-9007}}, journal = {{Physical Review Letters}}, number = {{8}}, title = {{{Microscopic Analysis of the Coherent Optical Generation and the Decay of Charge and Spin Currents in Semiconductor Heterostructures}}}, doi = {{10.1103/physrevlett.95.086606}}, volume = {{95}}, year = {{2005}}, } @article{23507, abstract = {{A microscopic model is used to analyze gain and loss properties of (GaIn)(NAs)∕GaAs quantum wells in the 1.3–1.55μm range, including Auger and radiative recombination. The calculations show that, as long as good material quality can be achieved, growing highly compressively strained samples is preferable due to their specific band structure properties. Optimum laser operation is possible slightly above a peak gain of 1000cm−1 ⁠.}}, author = {{Schlichenmaier, C. and Thränhardt, A. and Meier, Torsten and Koch, S. W. and Chow, W. W. and Hader, J. and Moloney, J. V.}}, issn = {{0003-6951}}, journal = {{Applied Physics Letters}}, number = {{26}}, title = {{{Gain and carrier losses of (GaIn)(NAs) heterostructures in the 1300–1550 nm range}}}, doi = {{10.1063/1.2149371}}, volume = {{87}}, year = {{2005}}, } @inbook{43275, author = {{Meier, Torsten and Koch, S.W.}}, booktitle = {{Encyclopedia of Modern Optics}}, editor = {{Guenther, B. and Bayvel, L. and Steel, D.G.}}, pages = {{163--173}}, publisher = {{Elsevier}}, title = {{{COHERENT TRANSIENTS | Foundations of Coherent Transients in Semiconductors}}}, doi = {{10.1016/B0-12-369395-0/00754-5}}, year = {{2005}}, } @inproceedings{44121, abstract = {{Theory/experiment comparisons of optical properties of dilute nitride heterostructures are presented. A type I - type II transition in In0.23Ga0.77As/GaNxAs1−x heterostructures is identified. The model is used for a study of lasing in the 1.3-1.5μm range.}}, author = {{Meier, Torsten and Schlichenmaier, C. and Thränhardt, A. and Grüning, H. and Klar, Peter J. and Heimbrodt, Wolfram and Koch, S.W. and Chow, Weng W. and Hader, J. and Moloney, Jerome V.}}, booktitle = {{ Quantum Electronics and Laser Science Conference}}, isbn = {{1-55752-770-9}}, location = {{Baltimore, Maryland United States}}, publisher = {{Optical Society of America}}, title = {{{Analysis of dilute nitride semiconductor laser gain materials in the 1.3-1.5/spl mu/m range}}}, year = {{2005}}, } @article{23501, abstract = {{A set of (Ga0.77In0.23)As/Ga(NxAs1−x) heterostructures is studied by time-resolved photoluminescence. Four samples with nitrogen concentrations from x=0.48% up to x=2.2% are investigated at different temperatures and with different excitation densities. The experiments suggest that the heterostructure band offset is type I for x=0.48% and type II for x=2.2%. The situation is more complex for x=0.72% and x=1.25%, since these samples are close to the transition from type I to type II. The experimental findings are analyzed using a detailed microscopic theory. Numerical calculations describe the measured data well. In particular, the interpretation of the experimental results concerning the band alignment is confirmed by the theoretical analysis.}}, author = {{Hantke, K. and Heber, J. D. and Schlichenmaier, C. and Thränhardt, A. and Meier, Torsten and Kunert, B. and Volz, K. and Stolz, W. and Koch, S. W. and Rühle, W. W.}}, issn = {{1098-0121}}, journal = {{Physical Review B}}, number = {{16}}, title = {{{Time-resolved photoluminescence of type-I and type-II (GaIn) As/Ga (NAs) heterostructures}}}, doi = {{10.1103/physrevb.71.165320}}, volume = {{71}}, year = {{2005}}, } @article{23496, abstract = {{The optical and electronic properties of semiconductor heterostructures in the vicinity of photonic crystals are discussed. The theoretical approach provides a self-consistent solution of the dynamics of the electromagnetic field and the material excitations. Due to the influence of the structured dielectric environment on the Coulomb interaction, the exciton resonances and the quasiequilibrium carrier densities in the spatially homogeneous semiconductor become space dependent. It is demonstrated that these inhomogeneities lead to distinct modifications of the optical absorption and gain spectra. As an application, numerically calculated density-dependent optical spectra are analyzed for an array of semiconductor quantum wires which are close to a two-dimensional photonic crystal. The spatial inhomogeneities result in novel excitonic absorption features and modification of the optical gain in these structures.}}, author = {{Reichelt, Matthias and Pasenow, B. and Meier, Torsten and Stroucken, T. and Koch, S. W.}}, issn = {{1098-0121}}, journal = {{Physical Review B}}, number = {{3}}, title = {{{Spatially inhomogeneous optical gain in semiconductor photonic-crystal structures}}}, doi = {{10.1103/physrevb.71.035346}}, volume = {{71}}, year = {{2005}}, }