@article{43305, abstract = {{Pump-probe experiments on high-quality InxGa1−x As quantum wells are used to investigate the influence of light-hole excitons on the optical Stark effect. For anticircular polarization of pump and probe pulses and a moderate negative detuning of the pump energy, a redshift of the heavy-hole resonance is observed. However, with increasingly negative detuning a transition from this redshift to a blueshift is found. Microscopic calculations that include both heavy holes and light holes reproduce the experimental results. The theoretical analysis shows that the observation of the redshift depends very sensitively on the detuning of the pump pulses and the heavy-hole to light-hole splitting.}}, author = {{Meier, Torsten and Brick, P. and Ell, C. and Khitrova, G. and Gibbs, H.M. and Sieh, C. and Koch, S.W.}}, journal = {{Physical Review B}}, number = {{7}}, publisher = {{American Physical Society}}, title = {{{Influence of Light Holes on the Heavy-Hole Excitonic Optical Stark Effect}}}, doi = {{10.1103/PhysRevB.64.075323}}, volume = {{64}}, year = {{2001}}, } @article{43304, abstract = {{The coherent dynamics of magnetoexcitons in semiconductor nanorings following pulsed optical excitation is studied. The calculated temporal evolution of the excitonic dipole moment may be understood as a superposition of the relative motion of electrons and holes and a global circular motion associated with the magnetic-field splitting of these states. This dynamics of the electron-hole pairs can be generated either by local optical excitation of an ordered ring or, alternatively, by homogeneous excitation of rings with broken rotational symmetry due to disorder or band tilting.}}, author = {{Meier, Torsten and Maschke, K. and Thomas, P. and Koch, S.W.}}, journal = {{The European Physical Journal B - Condensed Matter and Complex Systems}}, pages = {{599--606}}, publisher = {{EDP Sciences, Springer-Verlag}}, title = {{{Coherent Dynamics of Magnetoexcitons in Semiconductor Nanorings}}}, doi = {{10.1007/s100510170305}}, volume = {{19}}, year = {{2001}}, } @inproceedings{43614, abstract = {{The dynamics of optically generated electron-hole pairs is investigated in a disordered semiconductor nanowire. The particle pairs are generated by short laser pulses and their dynamics is followed using the Heisenberg equation of motion. Is is shown that Coulomb-correlation acts against localization in the case of the two-interacting particles (TIP) problem. Furthermore, currents are generated using a coherent combination of full-gap and half-gap pulses. The subsequent application of a full-gap pulse after time τ produces an intraband echo phenomenon 2τ time later. The echo current is shown to depend on the mass ratio between the electrons and the holes.}}, author = {{Meier, Torsten and Varga, I. and Schlichenmaier, C. and Maschke, K. and Thomas, P. and Koch, S.W.}}, booktitle = {{Proceedings of the XXXVIth Rencontres de Moriond on Electronic Correlations: From Meso-Physics to Nano-Physics}}, editor = {{Martin, Thierry and Tran Thanh Van, J. and Montambaux, Gilles}}, location = {{Les Arcs, France}}, pages = {{343--347}}, publisher = {{EDP Sciences}}, title = {{{Dynamics of Coulomb-correlated electron-hole pairs in disordered semiconductor nanowires}}}, doi = {{10.48550/arXiv.cond-mat/0111452}}, year = {{2001}}, } @article{43308, abstract = {{A microscopic many-body theory for the optical and electronic properties of semiconductors is reviewed with an emphasis on the role of correlation effects. At the semiclassical level, the semiconductor Bloch equations include many-body effects via bandgap and field renormalization as well as correlation contributions representing two electron-hole pair amplitudes, excitonic populations, and coupled interband and intraband coherences. These Coulomb interaction induced carrier correlations lead to characteristic signatures in nonlinear semiconductor spectroscopy. At the fully quantum mechanical level the dominant light-matter correlations are described by coupled semiconductor Bloch and luminescence equations. Excitonic emission properties of quantum well and microcavity systems are discussed, including effects such as coherent signatures in the secondary emission and coherent control of the emitted light.}}, author = {{Meier, Torsten and Kira, M. and Koch, S.W.}}, journal = {{Journal of Optics B: Quantum and Semiclassical Optics}}, number = {{5}}, publisher = {{IOP Publishing}}, title = {{{Correlation effects in the excitonic optical properties of semiconductors}}}, doi = {{10.1088/1464-4266/3/5/201}}, volume = {{3}}, year = {{2001}}, } @article{43309, abstract = {{The nonlinear optical response of a ZnSe single quantum well is investigated by spectrally resolving a wave-mixing signal using a three-beam configuration. A delayed third pulse with direction k3 leads to coherent oscillations in the spectrum emitted in 2k2–k1. Polarization-dependent measurements highlight the importance of higher-order Coulomb correlations as the dominant coupling mechanism between the three pulses. The experimental results are well explained by microscopic calculations including four-particle correlations up to fifth order in the fields.}}, author = {{Meier, Torsten and Wagner, H.P. and Tranitz, H.-P. and Reichelt, Matthias and Koch, S.W.}}, journal = {{Physical Review B}}, number = {{23}}, publisher = {{American Physical Society}}, title = {{{Coherent spectral oscillations in multiwave mixing}}}, doi = {{10.1103/PhysRevB.64.233303}}, volume = {{64}}, year = {{2001}}, } @inproceedings{44129, abstract = {{Summary form only given. Since the original discovery of the excitonic optical Stark effect, substantial progress has been made in the understanding of this ultrafast nonlinear optical effect. Recently, a red shift of the excitonic absorption line has been reported using low intensity excitation detuned 4.5 meV below the 1s-heavy-hole (hh) resonance and cross-circularly-polarized pulses. This was attributed to higher-order Coulomb correlations, interpretable as bound and unbound two-exciton states and memory effects. For co-circularly polarized pulses the well-known blue shift was found. Here we present a related effect occurring in the higher-intensity regime. Standard pump-probe experiments were performed on high-quality 8.5 nm-thick In/sub 0.04/Ga/sub 0.96/As multiple quantum well (MQW) samples.}}, author = {{Meier, Torsten and Chatterjee, S. and Brick, P. and Ell, C. and Gibbs, H.M. and Khitrova, G. and Sieh, C. and Koch, S.W.}}, booktitle = {{Coherent optical nonlinearities in normal mode microcavities}}, isbn = {{1-55752-663-X}}, location = {{Baltimore, MD, USA}}, pages = {{196--197}}, publisher = {{Optical Society of America}}, title = {{{The excitonic Stark effect: Absorption splitting and the influence of the light-hole exciton}}}, doi = {{10.1109/QELS.2001.962058}}, year = {{2001}}, } @inproceedings{44128, abstract = {{Summary form only given. When a quantum-well exciton transition is resonant with a single mode of a high-Q microcavity the linear reponse of the coupled system may be described in terms of normal modes ("cavity polaritons"), which arise as a result of the interplay of absorption and dispersion of the exciton transition within the cavity. The nonlinear response of these systems has often been discussed in terms of "polaritonic nonlinearities". It is desirable to investigate the nonlinearities of normal-mode microcavities (NMC's) at the same level and to determine if the microscopic theory accounting for the bare-QW response also quantitatively accounts for the normal-mode nonlinear response. We report here an extensive series of pump-probe experiments, investigating the time-resolved reflectivity of an NMC as a function of pump and probe polarization and pump fluence.}}, author = {{Meier, Torsten and Lee, Y-.S and Norris, T.B. and Khitrova, G. and Gibbs, H.M. and Sieh, C. and Koch, S.W. and Jahnke, F.}}, booktitle = {{Quantum Electronics and Laser Science Conference}}, isbn = {{1-55752-663-X}}, location = {{Baltimore, MD, USA}}, pages = {{230--231}}, publisher = {{Optical Society of America}}, title = {{{Coherent optical nonlinearities in normal mode microcavities}}}, doi = {{10.1109/QELS.2001.962141}}, year = {{2001}}, } @inproceedings{44130, abstract = {{Summary form only given. Optical and electronic properties of semiconductor heterostructures are strongly influenced by inherent disorder effects. The disorder consists of alloy disorder in ternary or quaternary compound semiconductors and interface roughness in semiconductor quantum wells. The spatial scales of disorder depend on the growth process. The disorder scale has up to now been extremely difficult to determine by macroscopic optical experiments. Here, we use excitons and biexcitons as mesoscopic probes in coherent excitation spectroscopy (CES) to reveal the spatial scale of disorder.}}, author = {{Meier, Torsten and Finger, E. and Kraft, S. and Hofmann, M. and Nau, S. and Bernatz, G. and Stolz, W. and Thomas, P. and Koch, S.W. and Rühle, W.W.}}, booktitle = {{Quantum Electronics and Laser Science Conference}}, isbn = {{1-55752-663-X}}, location = {{Baltimore, MD, USA}}, pages = {{269}}, publisher = {{Optical Society of America}}, title = {{{Excitons and biexcitons as mesoscopic probes of disorder in semiconductor heterostructures}}}, doi = {{10.1109/QELS.2001.962232}}, year = {{2001}}, } @article{13751, author = {{Esser, N. and Schmidt, Wolf Gero and Cobet, C. and Fleischer, K. and Shkrebtii, A. I. and Fimland, B. O. and Richter, W.}}, issn = {{0734-211X}}, journal = {{Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures}}, number = {{5}}, title = {{{Atomic structure and optical anisotropy of III–V(001) surfaces}}}, doi = {{10.1116/1.1394730}}, volume = {{19}}, year = {{2001}}, } @article{13753, author = {{Pulci, O. and Schmidt, Wolf Gero and Bechstedt, F.}}, issn = {{0031-8965}}, journal = {{physica status solidi (a)}}, number = {{1}}, pages = {{105--110}}, title = {{{Structure and Energetics of P-rich GaP(001) Surfaces}}}, doi = {{10.1002/1521-396x(200103)184:1<105::aid-pssa105>3.0.co;2-d}}, volume = {{184}}, year = {{2001}}, } @article{13847, author = {{Hingerl, K and Balderas-Navarro, R.E and Bonanni, A and Tichopadek, P and Schmidt, Wolf Gero}}, issn = {{0169-4332}}, journal = {{Applied Surface Science}}, pages = {{769--776}}, title = {{{On the origin of resonance features in reflectance difference data of silicon}}}, doi = {{10.1016/s0169-4332(01)00114-3}}, volume = {{175-176}}, year = {{2001}}, } @article{13849, author = {{Schmidt, Wolf Gero and Bechstedt, F. and Bernholc, J.}}, issn = {{0163-1829}}, journal = {{Physical Review B}}, title = {{{Terrace and step contributions to the optical anisotropy of Si(001) surfaces}}}, doi = {{10.1103/physrevb.63.045322}}, volume = {{63}}, year = {{2001}}, } @article{43318, abstract = {{The density-dependent absorption in the presence of incoherent occupations of excitons and electron–hole pairs is analyzed including many-body correlations represented by exciton to two-exciton transitions. At low temperatures the exciton resonance is bleached and shifts to higher energies with increasing density. For higher temperature, the blue shift disappears and pure bleaching is obtained.}}, author = {{Meier, Torsten and Koch, S.W.}}, journal = {{physica status solidi (b)}}, number = {{1}}, pages = {{211--214}}, publisher = {{WILEY‐VCH Verlag Berlin GmbH}}, title = {{{Analysis of Excitonic Absorption Changes Induced by Incoherent Exciton and Electron-Hole-Pair Populations}}}, doi = {{10.1002/1521-3951(200009)221:1<211::AID-PSSB211>3.0.CO;2-L}}, volume = {{221}}, year = {{2000}}, } @article{43314, abstract = {{Two phase-locked pulses are used to coherently excite excitonic polarizations. It is shown that the second pulse can either be strongly amplified by taking up energy gained from the destruction of the exciton polarization or can be decreased drastically by giving up all its energy to excitons. Both the temporal and the spectral signatures of the transmitted pulse shapes agree well with model calculations.}}, author = {{Meier, Torsten and Yee, D.S. and Yee, K.J. and Hohng, S.C. and Kim, D.S. and Koch, S.W.}}, journal = {{Physical review letters}}, number = {{15}}, publisher = {{American Physical Society}}, title = {{{Coherent Control of Absorption and Free Polarization Decay in GaAs Quantum Wells: Time and Spectral Domain Studies}}}, doi = {{10.1103/PhysRevLett.84.3474}}, volume = {{84}}, year = {{2000}}, } @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}}, }