@article{13736, author = {{Schmidt, Wolf Gero and Bechstedt, F. and Lu, W. and Bernholc, J.}}, issn = {{0163-1829}}, journal = {{Physical Review B}}, pages = {{0855334}}, title = {{{Interplay of surface reconstruction and surface electric fields in the optical anisotropy of GaAs(001)}}}, doi = {{10.1103/physrevb.66.085334}}, volume = {{66}}, year = {{2002}}, } @article{13741, author = {{Schmidt, Wolf Gero and Bechstedt, F. and Fleischer, K. and Cobet, C. and Esser, N. and Richter, W. and Bernholc, J. and Onida, G.}}, issn = {{0031-8965}}, journal = {{physica status solidi (a)}}, number = {{4}}, pages = {{1401--1409}}, title = {{{GaAs(001): Surface Structure and Optical Properties}}}, doi = {{10.1002/1521-396x(200112)188:4<1401::aid-pssa1401>3.0.co;2-1}}, volume = {{188}}, year = {{2002}}, } @article{13742, author = {{Bechstedt, F. and Schmidt, Wolf Gero and Hahn, P.H.}}, issn = {{0031-8965}}, journal = {{physica status solidi (a)}}, number = {{4}}, pages = {{1383--1392}}, title = {{{Towards a Complete Many-Body Description: Optical Response of Real Surfaces}}}, doi = {{10.1002/1521-396x(200112)188:4<1383::aid-pssa1383>3.0.co;2-g}}, volume = {{188}}, year = {{2002}}, } @article{13738, author = {{Schmidt, Wolf Gero and Bechstedt, F. and Bernholc, J.}}, issn = {{0169-4332}}, journal = {{Applied Surface Science}}, pages = {{264--268}}, title = {{{GaAs(001) surface reconstructions: geometries, chemical bonding and optical properties}}}, doi = {{10.1016/s0169-4332(01)00862-5}}, volume = {{190}}, year = {{2002}}, } @article{13740, author = {{Hahn, P. H. and Schmidt, Wolf Gero and Bechstedt, F.}}, issn = {{0031-9007}}, journal = {{Physical Review Letters}}, number = {{1}}, title = {{{Bulk Excitonic Effects in Surface Optical Spectra}}}, doi = {{10.1103/physrevlett.88.016402}}, volume = {{88}}, year = {{2002}}, } @article{13739, author = {{Schmidt, Wolf Gero}}, issn = {{0947-8396}}, journal = {{Applied Physics A: Materials Science & Processing}}, pages = {{89--99}}, title = {{{III-V compound semiconductor (001) surfaces}}}, doi = {{10.1007/s003390101058}}, volume = {{75}}, year = {{2002}}, } @article{13737, author = {{Seino, K. and Schmidt, Wolf Gero and Bechstedt, F. and Bernholc, J.}}, issn = {{0039-6028}}, journal = {{Surface Science}}, pages = {{406--410}}, title = {{{Structure and energetics of Ga-rich GaAs() surfaces}}}, doi = {{10.1016/s0039-6028(02)01278-5}}, volume = {{507-510}}, year = {{2002}}, } @article{8767, author = {{Reuter, Dirk and Meier, Cedrik and Álvarez, M. A. Serrano and Wieck, A. D.}}, issn = {{0003-6951}}, journal = {{Applied Physics Letters}}, pages = {{377--379}}, title = {{{Increased thermal budget for selectively doped heterostructures by employing AlAs/GaAs superlattices}}}, doi = {{10.1063/1.1386618}}, volume = {{79}}, year = {{2001}}, } @inbook{43303, abstract = {{This chapter focuses on the carrier interaction effects—that is, the many-body Coulomb correlations and their influence on band-gap semiconductor optical nonlinearities. The near band-gap semiconductor response is determined by the optical interaction with the resonant or near resonant material polarization that may result in the excitation of carriers (electron–hole pairs) and/or transient coherent nonlinearities. The microscopic analysis of these effects requires the investigation of the relevant quasi-particles and their interactions. Whereas the basic occurrence of a blue shift can be motivated already based on a simple two-level model, a more detailed understanding of the optical Stark effect in semiconductors requires a microscopic modeling of the relevant bands as well as the inclusion of the many-body Coulomb interaction. Compensations among the first- and higher-order Coulomb terms at the spectral positions of the exciton are obtained in the differential absorption induced by incoherent occupations.}}, author = {{Meier, Torsten and Koch, S.W.}}, booktitle = {{Ultrafast Physical Processes in Semiconductors}}, editor = {{Tsen, K.T.}}, isbn = {{978-0-12-752176-3}}, pages = {{231--313}}, publisher = {{Elsevier}}, title = {{{Coulomb correlation signatures in the excitonic optical nonlinearities of semiconductors}}}, doi = {{10.1016/S0080-8784(01)80172-1}}, volume = {{67}}, year = {{2001}}, } @article{43307, abstract = {{The influence of fifth-order coherences on the spectrally resolved four-wave mixing response of predominantly homogeneously broadened quasi-two-dimensional excitons is studied. Fifth-order signatures are discussed as a function of spectral position and excitation polarization. An exciton–biexciton beating for positive delay times is the dominant effect, which is pronounced at the exciton–biexciton transition for collinearly polarized excitation and at the exciton transition for cross-linearly polarized excitation. For negative delay times and collinearly polarized excitation a pronounced exciton–biexciton beating at the exciton resonance is observed that is vanishing for long negative delays owing to the faster dephasing in the two-exciton continuum compared with the bound biexciton state. These results are in qualitative agreement with microscopic model calculations that include the coherent dynamics of one- and two-exciton resonances up to the fifth order in the optical field.}}, author = {{Meier, Torsten and Langbein, W. and Koch, S.W. and Hvam, J.M.}}, journal = {{Journal of the Optical Society of America B}}, number = {{9}}, pages = {{1318--1325}}, publisher = {{Optical Society of America}}, title = {{{Spectral signatures of χ(5) processes in four-wave mixing of homogeneously broadened excitons}}}, doi = {{10.1364/JOSAB.18.001318}}, volume = {{18}}, year = {{2001}}, } @article{43306, abstract = {{Linear and nonlinear optical absorption spectra are studied theoretically for semiconductor nanorings penetrated by a magnetic field. Due to the Aharanov-Bohm effect the spectral position as well as the oscillator strength of the exciton change periodically as function of the magnetic flux enclosed by the ring. In the nonlinear differential absorption spectra it is found that the magnetic field strongly modifies Coulomb many-body correlations. In particular, the magnetic-field-induced increase of the exciton binding energy is accompanied by a decrease of the biexciton binding energy. The persistence of these effects in the presence of energetic disorder is analyzed.}}, author = {{Meier, Torsten and Thomas, P. and Koch, S.W.}}, journal = {{The European Physical Journal B - Condensed Matter and Complex Systems}}, pages = {{249--256}}, publisher = {{EDP sciences}}, title = {{{Linear and nonlinear optical properties of semiconductor nanorings with magnetic field and disorder-Influence on excitons and biexcitons}}}, doi = {{10.1007/s100510170133}}, volume = {{22}}, year = {{2001}}, } @inbook{43302, abstract = {{In this chapter a microscopic many-body theory is reviewed that allows one to compute the linear and nonlinear optical properties of semiconductor superlattices in the presence of homogeneous electric fields applied in the growth direction. The theory includes the process of optical excitation, the Coulomb interaction among the carriers, carrier-phonon coupling, and the acceleration induced by the electric field. Coherent phenomena induced by dc and ac fields, like Bloch oscillations and dynamical localization, are introduced and discussed. The theoretical analysis concentrates on the signatures and observability of such phenomena in linear and nonlinear optical experiments.}}, author = {{Meier, Torsten and Thomas, P. and Koch, S.W.}}, booktitle = {{Ultrafast Phenomena in Semiconductors}}, editor = {{Tsen, K.T.}}, isbn = {{978-1-4612-6562-7}}, pages = {{1--92}}, publisher = {{Springer}}, title = {{{Coherent Dynamics of Photoexcited Semiconductor Superlattices with Applied Homogeneous Electric Fields}}}, doi = {{10.1007/978-1-4613-0203-2_1}}, year = {{2001}}, } @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}}, }