@inproceedings{44134, author = {{Meier, Torsten and Brick, P. and Ell, C. and Khitrova, G. and Gibbs, H.M. and Koch, S.W.}}, booktitle = {{Quantum Electronics and Laser Science Conference (QELS 2000)}}, isbn = {{1-55752-608-7}}, issn = {{1094-5695}}, location = {{San Francisco, California United States}}, title = {{{χ(5)-signatures in the optical Stark effect}}}, year = {{2000}}, } @article{44136, author = {{Meier, Torsten and Chernyak, V. and Tretiak, S. and Tsiper, EV.. and Mukamel, S.}}, journal = {{Condensed Matter Theories}}, pages = {{289--298}}, title = {{{Semiclassical Effective Hamiltonian For Coupled Electronic And Nuclear Optical Response}}}, volume = {{14}}, year = {{2000}}, } @article{43315, abstract = {{A microscopic many-body theory for the linear and nonlinear optical properties of semiconductor superlattices subjected to electric fields is presented. The approach has been used for the analysis of various processes related to the Bloch-oscillation dynamics of carriers in static fields and for investigating dynamical localization induced by alternating fields. It is shown that the theory describes very well experimental field-modulated absorption spectra of a strongly coupled superlattice. Furthermore, characteristic signatures, such as negative absorption in the short-pulse optical response of superlattices subjected simultaneously to static and alternating electric fields are predicted.}}, author = {{Meier, Torsten and Kolbe, H.J. and Thränhardt, A. and Weiser, G. and Thomas, P. and Koch, S.W.}}, journal = {{Physica E: Low-dimensional Systems and Nanostructures}}, number = {{1-2}}, pages = {{267--273 }}, publisher = {{North-Holland}}, title = {{{Coherent dynamics of photoexcited semiconductor superlattices in homogeneous electric fields}}}, doi = {{10.1016/S1386-9477(99)00274-X}}, volume = {{7}}, year = {{2000}}, } @article{43310, abstract = {{Local ultrafast optical excitation of electron–hole pairs in disordered semiconductors provides the possibility to observe experimentally interaction-assisted propagation of correlated quantum particles in a disordered environment. In addition to the interaction driven delocalization known for the conventional single-band TIP-(two-interacting-particles)-problem the semiconductor model has a richer variety of physical parameters that give rise to new features in the temporal dynamics. These include different masses, correlated versus anticorrelated disorder for the two particles, and dependence on spectral position of excitation pulse.}}, author = {{Meier, Torsten and Thomas, P. and Varga, I. and Lemm, T. and Golub, J.E. and Maschke, K. and Koch, S.W.}}, journal = {{physica status solidi (b)}}, number = {{1}}, pages = {{125--132}}, publisher = {{WILEY‐VCH Verlag Berlin GmbH}}, title = {{{Propagation of Coulomb-Correlated Electron-Hole Pairs in Semiconductors with Correlated and Anticorrelated Disorder}}}, doi = {{10.1002/(SICI)1521-3951(200003)218:1<125::AID-PSSB125>3.0.CO;2-7}}, volume = {{218}}, year = {{2000}}, } @article{43311, abstract = {{First, we study coupling of excitons in different quantum-well islands by coherent excitation spectroscopy and find that excitons in different islands are not coherently coupled. Second, we investigate exciton and biexciton binding energies in inhomogeneously broadened (GaIn)As/Ga(PAs) multi quantum wells. A strong increase of the 1s–2s-splitting with increasing exciton localization is found, whereas the biexciton binding energy shows a very weak decrease with increasing localization.}}, author = {{Meier, Torsten and Euteneuer, A. and Finger, E. and Stolz, W. and Thomas, P. and Koch, S.W. and Hofmann, M. and Rühle, W.W. and Hey, R. and Ploog, K.H.}}, journal = {{physica status solidi (a)}}, number = {{1}}, pages = {{183--188}}, publisher = {{WILEY‐VCH Verlag Berlin GmbH}}, title = {{{Investigation of Disordered Semiconductor Quantum Wells by Coherent Excitation Spectroscopy}}}, doi = {{10.1002/1521-396X(200003)178:1<183::AID-PSSA183>3.0.CO;2-Q}}, volume = {{178}}, year = {{2000}}, } @article{43313, abstract = {{Microscopic calculations including energetic disorder and Coulomb correlations up to third order in the laser field are performed. The resulting four-wave-mixing signals show polarization-dependent dephasing induced by diagonal disorder. The correct modeling of this disorder-induced dephasing requires the proper inclusion of Coulomb correlations. The theoretical results are in good qualitative agreement with measurements performed on a variety of quantum-well samples.}}, author = {{Meier, Torsten and Weiser, S. and Möbius, J. and Euteneuer, A. and Mayer, E.J. and Stolz, W. and Hofmann, M. and Rühle, W.W. and Thomas, P. and Koch, S.W.}}, journal = {{Physical Review B}}, number = {{19}}, publisher = {{American Physical Society}}, title = {{{Disorder-induced Dephasing in Semiconductors}}}, doi = {{10.1103/PhysRevB.61.13088}}, volume = {{61}}, year = {{2000}}, } @inproceedings{44131, abstract = {{A number of experiments yielded a polarization-dependent decay of the time-integrated four-wavemixing (TI-FWM). Often, the TI-FWM decays more rapidly for linear perpendicular than for linear parallel polarized incident pulses. It was suspected that this difference in the decay times is related to the inhomogeneous linewidth of the exciton, i.e. to disorder [1], On the other hand, it was demonstrated in a large number of recent publications, that the understanding of polarization-dependent FWM and pump-probe experiments following excitonic excitation requires the treatment of Coulomb correlations beyond the Hartree-Fock level. For not too strong disorder, these correlations still remain important and influence the nonlinear optical response [2]. A meaningful analysis of disorder effects thus has to include correlations.}}, author = {{Meier, Torsten and Weiser, S. and Möbius, J. and Euteneuer, A. and Mayer, E.J. and Stolz, W. and Hofmann, M. and Rühle, W.W. and Thomas, P. and Koch, S.W.}}, booktitle = {{International Quantum Electronics Conference}}, isbn = {{0-7803-6318-3}}, location = {{Nice, France}}, publisher = {{IEEE}}, title = {{{Analysis of disorder-induced dephasing}}}, doi = {{10.1109/IQEC.2000.908038}}, year = {{2000}}, } @inproceedings{44132, abstract = {{Polarization dependent excitonic absorption changes have been studied recently for excitation with weak pump pulses [1]. It was shown, that for both resonant and off-resonant excitation even in the low-intensity χ(3)-limit many-body Coulomb correlations strongly contribute the optical response [1]. Here we investigate, how the coherent pump-induced absorption changes vary with the pump intensity, by analyzing the next higher, i.e. the fifth-order contributions.}}, author = {{Meier, Torsten and Koch, S.W. and Brick, P. and Ell, C. and Khitrova, G. and Gibbs, H.M.}}, booktitle = {{International Quantum Electronics Conference}}, isbn = {{0-7803-6318-3}}, location = {{Nice, France}}, publisher = {{IEEE}}, title = {{{Influence of correlations on intensity dependent excitonic absorption changes}}}, doi = {{10.1109/IQEC.2000.908034}}, year = {{2000}}, } @inproceedings{44133, abstract = {{by inherent disorder effects. Inhomogeneous broadening is the most obvious consequence of disorder and an inhomogeneously broadened exciton line might be considered as a superposition of homogeneously broadened subensembles of excitons. However, a possible coherent coustructures and lead to effects like disorder induced dephasing [1].}}, author = {{Meier, Torsten and Finger, E. and Kraft, S. and Euteneuer, A. and Hofmann, M. and Stolz, W. and Thomas, P. and Koch, S.W. and Rühle, W.W.}}, booktitle = {{International Quantum Electronics Conference}}, isbn = {{0-7803-6318-3}}, location = {{Nice, France}}, publisher = {{IEEE}}, title = {{{Coherent coupling in inhomogeneously broadened exciton ensembles}}}, doi = {{10.1109/IQEC.2000.908097}}, year = {{2000}}, } @article{43317, abstract = {{The intensity dependence of pump-induced excitonic absorption changes is studied in high-quality In0.04Ga0.96 As quantum wells for different detunings and polarization configurations. For resonant excitation with increasing pump intensity a saturation of both the exciton bleaching and the induced absorption due to two-exciton resonances is observed, whereas for pumping below the exciton a characteristic polarization dependence of higher-order contributions to the optical Stark effect is found. Microscopic calculations including Coulomb correlations show that the experimental observations can be described by the coherent dynamics of single- and two-exciton resonances up to fifth order in the optical field.}}, author = {{Meier, Torsten and Koch, S.W. and Brick, P. and Ell, C. and Khitrova, G. and Gibbs, H.M.}}, journal = {{Physical Review B}}, number = {{7}}, publisher = {{American Physical Society}}, title = {{{Signatures of Correlations in Intensity Dependent Excitonic Absorption Changes}}}, doi = {{10.1103/PhysRevB.62.4218}}, volume = {{62}}, year = {{2000}}, } @article{43323, abstract = {{The differential absorption of a GaAs single quantum well is studied for resonant pumping at either the heavy- or light-hole exciton resonances using different polarization configurations. For all excitation conditions the observed spectra show bleaching of both excitons, revealing strong coupling between the heavy- and light-hole excitons. Microscopic calculations which include four-particle correlations representing the various two-exciton states qualitatively reproduce the experimental findings. A mixed heavy-hole–light-hole biexciton is also clearly identified as an induced resonance in a GaAs system.}}, author = {{Meier, Torsten and Koch, S.W. and Phillips, M. and Wang, H.}}, journal = {{Physical Review B}}, number = {{19}}, publisher = {{American Physical Society}}, title = {{{Strong coupling of heavy- and light-hole excitons induced by many-body correlations}}}, doi = {{10.1103/PhysRevB.62.12605}}, volume = {{62}}, year = {{2000}}, } @article{43316, abstract = {{The phonon scattering assisted luminescence of semiconductor quantum well excitons after short pulse excitation is investigated. The presented analysis is based on the low-density limit of a set of equations for quantum correlation functions for electrons, phonons, and photons. The dynamics of the correlation functions describes the optical excitation and the decay of the coherent exciton polarization as well as the generation of an incoherent exciton occupation and its luminescence decay. Numerical solutions of the equations of motion demonstrate strong competition effects of the exciton-phonon and the exciton-photon interaction on a picosecond time scale and lead to a nonmonotonous temperature dependence of the time-resolved spontaneous emission. The angle resolved emission resembles the generation and decay dynamics of the exciton density for different in-plane momenta.}}, author = {{Meier, Torsten and Thränhardt, A. and Kuckenberg, S. and Knorr, A. and Koch, S.W.}}, journal = {{Physical Review B}}, number = {{4}}, pages = {{2706--2720}}, title = {{{Quantum theory of phonon-assisted exciton formation and luminescence in semiconductor quantum wells}}}, doi = {{10.1103/PhysRevB.62.2706}}, volume = {{62}}, year = {{2000}}, } @inproceedings{44135, abstract = {{Extensive recent studies have provided valuable understanding on the role of correlations between excitons in optical interactions in semiconductors.}}, author = {{Meier, Torsten and Phillips, M. and Wang, H. and Koch, S.W.}}, booktitle = {{Quantum Electronics and Laser Science Conference (QELS 2000)}}, isbn = {{1-55752-608-7}}, location = {{San Francisco, California United States}}, title = {{{Correlation-induced resonances in differential absorption of semiconductors}}}, year = {{2000}}, } @article{43312, abstract = {{Differential absorption spectra of high quality InGaAs quantum wells were measured by means of pump–probe spectroscopy as a function of pump–probe delay, for different polarizations of the pulses, and different spectral detunings of the pump beam with respect to the 1s heavy-hole exciton. A clear redshift of the heavy-hole resonance is observed for large detunings and opposite circularly polarized pulses. Microscopic calculations that include not only the Hartree-Fock contribution but also higher-order Coulomb correlations reproduce the experimental findings very well. It is shown that the redshift is caused by Coulomb memory effects and is further enhanced due to the presence of the bound biexciton.}}, author = {{Meier, Torsten and Brick, P. and Ell, C. and Hübner, M. and Prineas, J.P. and Khitrova, G. and Gibbs, H.M. and Sieh, C. and Jahnke, F. and Knorr, A. and Koch, S.W.}}, journal = {{physica status solidi (a)}}, number = {{1}}, pages = {{459--463}}, publisher = {{WILEY‐VCH Verlag Berlin GmbH}}, title = {{{Coulomb Memory Effects and Higher-Order Coulomb Correlations in the Excitonic Optical Stark Effect}}}, doi = {{10.1002/1521-396X(200003)178:1<459::AID-PSSA459>3.0.CO;2-2}}, volume = {{178}}, year = {{2000}}, } @article{43319, abstract = {{A phenomenological multi-exciton level scheme is used to calculate the excitonic differential absorption as measured in pump and probe experiments. Numerical results are compared to those obtained by a fully microscopic density-matrix theory. For resonant excitation, optimized parameters yield qualitative agreement, but the phenomenological approach soon reaches its limit for non-resonant pumping.}}, author = {{Meier, Torsten and Reichelt, Matthias and Sieh, C. and Koch, S.W.}}, journal = {{physica status solidi (b)}}, number = {{1}}, pages = {{249--252}}, publisher = {{WILEY‐VCH Verlag Berlin GmbH}}, title = {{{Comparison of the differential absorption obtained within a few-level model and the microscopic density-matrix theory}}}, doi = {{10.1002/1521-3951(200009)221:1<249::AID-PSSB249>3.0.CO;2-E}}, volume = {{221}}, year = {{2000}}, } @article{43320, abstract = {{A scheme to generate an experimentally measurable current echo is proposed where current pulses are induced by a sequence of phase coherent optical pulses. Based on microscopic calculations for a one-dimensional tight-bindig model of a disordered two-band semiconductor it is predicted that excitation sequences can be taylored such that after two induced time-delayed current pulses a current echo pulse results.}}, author = {{Meier, Torsten and Stippler, J. and Schlichenmaier, C. and Knorr, A. and Lindberg, M. and Thomas, P. and Koch, S.W.}}, journal = {{physica status solidi (b)}}, number = {{1}}, pages = {{379--384}}, publisher = {{WILEY‐VCH Verlag Berlin GmbH}}, title = {{{Current Echoes induced by Coherent Control}}}, doi = {{10.1002/1521-3951(200009)221:1<379::AID-PSSB379>3.0.CO;2-Z}}, volume = {{221}}, year = {{2000}}, } @article{43324, abstract = {{Dephasing, i.e. the decay of the optical interband polarization in a semiconductor results from destructive interference effects between different microscopic contributions. For a system without any disorder it is shown that the many-body Coulomb correlations lead to excitation-induced dephasing which becomes increasingly important at elevated excitation levels. The effect of disorder-induced dephasing is analyzed for low excitation levels, where the combined influence of excitonic, biexcitonic, and disorder scattering contributions lead to a temporal decay of the four-wave-mixing signal.}}, author = {{Meier, Torsten and Koch, S.W. and Jahnke, F. and Thomas, P.}}, journal = {{Applied Physics A}}, pages = {{511--517}}, publisher = {{Springer-Verlag}}, title = {{{Microscopic Theory of Optical Dephasing in Semiconductors}}}, doi = {{10.1007/s003390000707}}, volume = {{71}}, year = {{2000}}, } @article{43332, abstract = {{A model study of the characteristic signatures of carrier-correlation effects on the excitonic differential absorption spectra in semiconductors is presented. Using an effectively one-dimensional tight-binding system Coulomb-induced carrier-correlations up to third-order in the optical field are treated without additional approximations. To illustrate the influence of the different many-body contributions excitonic differential absorption spectra are computed for various polarizations and pump-probe time delays. The simultaneous influence of energetic disorder and correlations on the differential absorption spectra is discussed. Also presented are numerical results for the case when the semiconductor system is placed inside a microcavity in the strong-coupling regime. It is shown that the correlations induce characteristic signatures in the normal mode spectra.}}, author = {{Meier, Torsten and Sieh, C. and Knorr, A. and Jahnke, F. and Thomas, P. and Koch, S.W.}}, journal = {{The European Physical Journal B-Condensed Matter and Complex Systems}}, pages = {{407--421}}, publisher = {{Società Italiana di Fisica}}, title = {{{Influence of carrier correlations on the excitonic optical response including disorder and microcavity effects}}}, doi = {{10.1007/BF03219177}}, volume = {{11}}, year = {{1999}}, } @article{43334, abstract = {{A microscopic theory is applied to discuss coherent excitation effects in semiconductors. The theory is evaluated to analyze ultrafast absorption changes around the exciton resonance in semiconductor quantum-well structures where the relative strength of the different many-body contributions can be manipulated by proper selection of pump and probe polarizations. For two-band systems and oppositely circular polarization it is shown that Coulombic correlation dynamics dominates the optical response. As a consequence, the optical Stark effect in this configuration corresponds to a red shift of the exciton resonance in striking contrast to the usual atomic-like blue shift. The predictions are confirmed by experiments using high-quality InGaAs quantum-well systems.}}, author = {{Meier, Torsten and Koch, S.W. and Sieh, C. and Jahnke, F. and Knorr, A. and Brick, P. and Hübner, M. and Ell, C. and Prineas, J. and Khitrova , G. and Gibbs, H.M.}}, journal = {{Journal of luminescence}}, pages = {{1--6}}, publisher = {{Journal of luminescence}}, title = {{{Theory of coherent effects in semiconductors}}}, doi = {{10.1016/S0022-2313(99)00065-4}}, volume = {{83/84}}, year = {{1999}}, } @article{43333, abstract = {{Fluorescence line shapes and cooperative spontaneous emission in disordered one-dimensional molecular aggregates are calculated using closed expressions derived by applying the method of optimal fluctuation. A simple scaling relation Ls ∼ ωs-1/2 is established between the low temperature disorder-induced Stokes shift ωs and the superradiance enhancement factor Ls. Scaling of the Stokes shift with aggregate size, and the time-dependent Stokes shift are discussed as well. Excellent agreement is obtained with numerical simulations.}}, author = {{Meier, Torsten}}, journal = {{The Journal of Physical Chemistry A}}, number = {{49}}, pages = {{10294--10299}}, publisher = {{American Physical Society}}, title = {{{Scaling Of Fluorescence Stokes Shift And Superradiance Coherence Size In Disordered Molecular Aggregates}}}, doi = {{10.1021/jp991893ow}}, volume = {{103}}, year = {{1999}}, }