@inbook{23510, author = {{Meier, Torsten and Koch, Stephan W.}}, booktitle = {{Photonic Crystals: Advances in Design, Fabrication, and Characterization}}, editor = {{Busch, Kurt and Lölkes, Stefan and Wehrspohn, Ralf B. and Helmut Föll, Wiley}}, isbn = {{9783527404322}}, pages = {{43--62}}, publisher = {{Wiley‐VCH Verlag}}, title = {{{Semiconductor Optics in Photonic Crystal Structures}}}, doi = {{10.1002/3527602593.ch3}}, year = {{2004}}, } @article{43290, abstract = {{A nonequilibrium occupation distribution relaxes towards the Fermi-Dirac distribution due to electron-electron scattering even in finite Fermi systems. The dynamic evolution of this thermalization process assumed to result from an optical excitation is investigated numerically by solving a Boltzmann equation for the carrier populations using a one-dimensional disordered system. We focus on the short-time-scale behavior. The logarithmically long time scale associated with the glassy behavior of interacting electrons in disordered systems is not treated in our investigation. For weak disorder and short range interaction we recover the expected result that the relaxation rate is enhanced by disorder. For sufficiently strong disorder, however, we find an opposite trend due to the reduction of scattering probabilities originating from the strong localization of the single-particle states. Long-range interaction in this regime produces a similar effect. The relaxation rate is found to scale with the interaction strength, however, the interplay between the implicit and the explicit character of the interaction produces an anomalous exponent.}}, author = {{Meier, Torsten and Varga, I. and Thomas, P. and Koch, S.W.}}, journal = {{Physical Review B}}, number = {{11}}, publisher = {{American Physical Society}}, title = {{{Dynamics of short-time-scale energy relaxation of optical excitations due to electron-electron scattering in the presence of arbitrary disorder}}}, doi = {{10.1103/PhysRevB.68.113104}}, volume = {{68}}, year = {{2003}}, } @article{43289, abstract = {{A microscopic approach is presented to compute nonlinear optical properties of semiconductor surfaces. The method uses quasiparticle wave functions and dispersions obtained from ab initio band-structure theory as an input for Bloch equations which describe the optical properties. Excitonic effects in the linear absorption spectra of the Si(111)- (2×1) surface are obtained by integrating equations of motion. To demonstrate the applicability of the approach for analyzing nonlinear optical properties, ultrafast light-intensity-dependent absorption changes of the surface exciton are predicted. The numerical results discuss the optical Stark effect and spectral oscillations of the surface exciton which can both be observed in pump-probe experiments.}}, author = {{Meier, Torsten and Reichelt, Matthias and Koch, S.W. and Rohlfing, M.}}, journal = {{Physical Review B}}, number = {{4}}, publisher = {{American Physical Society}}, title = {{{Theory for the nonlinear optical response of semiconductor surfaces: Application to the optical Stark effect and spectral oscillations of the Si(111)-(2x1) surface exciton}}}, doi = {{10.1103/PhysRevB.68.045330}}, volume = {{68}}, year = {{2003}}, } @article{43288, abstract = {{Signatures of exciton and two-exciton states in semiconductor systems are investigated experimentally and theoretically. A set of quantum well samples with different well widths is studied using coherent excitation spectroscopy. The experimental results are analyzed using a microscopic model demonstrating the importance of biexciton correlations and disorder effects. Additional numerical investigations of absorption changes in small nanorings are employed to analyze optical transitions from two-exciton to three-exciton resonances.}}, author = {{Meier, Torsten and Sieh, C. and Finger, E. and Stolz, W. and Rühle, W.W. and Koch, S.W. and Thomas, P.}}, journal = {{physica status solidi (b)}}, number = {{3}}, pages = {{537--540}}, publisher = {{WILEY‐VCH Verlag}}, title = {{{Signatures of biexcitons and triexcitons in coherent non-degenerate semiconductor optics}}}, doi = {{10.1002/pssb.200303183}}, volume = {{238}}, year = {{2003}}, } @article{23508, abstract = {{A nonequilibrium occupation distribution relaxes towards the Fermi-Dirac distribution due to electron-electron scattering even in finite Fermi systems. The dynamic evolution of this thermalization process assumed to result from an optical excitation is investigated numerically by solving a Boltzmann equation for the carrier populations using a one-dimensional disordered system. We focus on the short-time-scale behavior. The logarithmically long time scale associated with the glassy behavior of interacting electrons in disordered systems is not treated in our investigation. For weak disorder and short range interaction we recover the expected result that the relaxation rate is enhanced by disorder. For sufficiently strong disorder, however, we find an opposite trend due to the reduction of scattering probabilities originating from the strong localization of the single-particle states. Long-range interaction in this regime produces a similar effect. The relaxation rate is found to scale with the interaction strength, however, the interplay between the implicit and the explicit character of the interaction produces an anomalous exponent.}}, author = {{Varga, Imre and Thomas, Peter and Meier, Torsten and Koch, Stephan W.}}, issn = {{0163-1829}}, journal = {{Physical Review B}}, number = {{11}}, title = {{{Dynamics of short-time-scale energy relaxation of optical excitations due to electron-electron scattering in the presence of arbitrary disorder}}}, doi = {{10.1103/physrevb.68.113104}}, volume = {{68}}, year = {{2003}}, } @article{43284, abstract = {{The quantum dynamics of an ensemble of interacting electrons in an array of random scatterers is treated using a new numerical approach for the calculation of average values of quantum operators and time correlation functions in the Wigner representation. This approach combines both molecular dynamics and Monte Carlo methods and computes numerical traces and spectra of the relevant dynamical quantities such as momentum–momentum correlation functions and spatial dispersions. Considering, as an application, a system with fixed scatterers, the results clearly demonstrate that the many-particle interaction between the electrons can lead to an enhancement of the conductivity at intermediate densities.}}, author = {{Meier, Torsten and Filinov, V.S. and Thomas, P. and Varga, I. and Bonitz, M. and Fortov, V.E and Koch, S.W.}}, journal = {{Journal of Physics A: Mathematical and General}}, number = {{22}}, pages = {{5905--5911}}, publisher = {{IOP Publishing}}, title = {{{Electronic transport in a one-dimensional random array of scatterers}}}, doi = {{10.1088/0305-4470/36/22/311}}, volume = {{36}}, year = {{2003}}, } @article{44124, abstract = {{The new method for solving Wigner–Liouville's type equations and studying dynamics of quantum particles has been developed within the Wigner formulation of quantum statistical mechanics. This approach combines both molecular dynamics and Monte Carlo methods and computes traces and spectra of the relevant dynamical quantities. Considering, as an application, the quantum dynamics of an ensemble of interacting electrons in an array of random scatterers clearly demonstrates that the many-particle interaction between the electrons can lead to an enhancement of the electrical conductivity.}}, author = {{Meier, Torsten and Filinov, V. and Thomas, P. and Bonitz, M. and Fortov, V. and Varga, I.}}, journal = {{physica status solidi (b)}}, number = {{1}}, pages = {{40--46}}, title = {{{Wigner approach to quantum dynamics simulations of the interacting carriers in disordered systems}}}, doi = {{10.1002/pssb.200303617}}, volume = {{241}}, year = {{2003}}, } @inproceedings{44125, author = {{Meier, Torsten}}, isbn = {{1-55752-759-8}}, location = {{Tucson, Arizona United States}}, publisher = {{Optical Society of America}}, title = {{{Semiconductor photonic-crystal structures: Optical spectra and carrier dynamics}}}, doi = {{10.1364/FIO.2003.WU1}}, year = {{2003}}, } @article{43287, abstract = {{A novel microscopic approach for computing nonlinear optical properties of semiconductor surfaces is outlined. The linear and nonlinear response of the Si(111)-(2×1) surface is studied using a combination of ab-initio band-structure theory and equation of motion technique. The usefulness of the method is shown by reproducing known excitonic effects in the linear differential reflectivity spectrum. To additionally demonstrate the applicability of the approach for the nonlinear regime, the nonlinear optical response in Stark effect configuration is examined.}}, author = {{Meier, Torsten and Reichelt, Matthias and Koch, S.W. and Rohlfing, M.}}, journal = {{physica status solidi (b)}}, number = {{3}}, pages = {{525--528}}, publisher = {{WILEY‐VCH Verlag}}, title = {{{Microscopic theory for the nonlinear optical response of semiconductor surfaces: Application to the optical Stark effect of the Si(111)-(2x1) surface exciton}}}, doi = {{10.1002/pssb.200303180}}, volume = {{238}}, year = {{2003}}, } @article{43286, abstract = {{Optical properties of a semiconductor quantum well in the vicinity of a two-dimensional photonic crystal are investigated. Due to the periodic spatial modulation of the dielectric environment the effective Coulomb interaction potential exhibits the periodicity of the photonic crystal. As a consequence, the excitonic binding energy varies periodically by up to 50% depending on the spatial position of the exciton relative to the structured dielectric. The self image charge effects result in a position dependent shift of the single-particle bandgap such that the spectral position of the absorption spectrum also develops the periodicity of the photonic surrounding.}}, author = {{Meier, Torsten and Eichmann, R. and Pasenow, B. and Thomas, P. and Koch, S.W.}}, journal = {{physica status solidi (b)}}, number = {{3}}, pages = {{439--442}}, publisher = {{WILEY‐VCH Verlag}}, title = {{{Semiconductor excitons in photonic crystals}}}, doi = {{10.1002/pssb.200303159}}, volume = {{238}}, year = {{2003}}, } @article{43283, abstract = {{Absorption spectra of semiconductor structures in photonic crystal environments are investigated numerically. It is shown that the periodic dielectric structuring changes the local optical and Coulomb interaction properties of semiconductor electron–hole excitations. The structurally induced modifications offer the possibility to design important aspects of the optoelectronic semiconductor properties.}}, author = {{Eichmann, R. and Pasenow, B. and Meier, Torsten and Stroucken, T. and Thomas, P. and Koch, S.W.}}, journal = {{Applied Physics Letters}}, number = {{3}}, pages = {{355--357}}, publisher = {{American Institute of Physics}}, title = {{{Semiconductor absorption in photonic crystals}}}, doi = {{10.1063/1.1537455}}, volume = {{82}}, year = {{2003}}, } @article{43285, author = {{Meier, Torsten and Thomas, P.}}, journal = {{Physik Journal}}, number = {{3}}, pages = {{53--59}}, title = {{{Echos in Festkörpern}}}, volume = {{2}}, year = {{2003}}, } @inbook{43273, author = {{Meier, Torsten and Pasenow, B. and Thomas, P. and Koch, S.W.}}, booktitle = {{Germany NIC Series, Vol. 20}}, editor = {{Wolf, Dietrich and Münster, Gernot and Kremer, Manfred}}, isbn = {{3-00-012372-5}}, pages = {{261--270}}, publisher = {{John von Neumann Institute for Computing}}, title = {{{Many-body Coulomb effects in the optical properties of semiconductor heterostructures}}}, volume = {{20}}, year = {{2003}}, } @article{4310, abstract = {{Nonlinear propagation of optical pulses through an extended bulk semiconductor is investigated using the coupled semiconductor Maxwell‐Bloch equations including excitation induced correlations. For short pulse excitation around the exciton resonance, the theory describes the development of polariton beats and their suppression at increasing input pulse intensities due to the coupling of single exciton states to the Coulomb‐correlated continuum of two‐exciton states. A comparison of the theoretical results with experimental observations for CdSe bulk material is presented.}}, author = {{Förstner, Jens and Knorr, A. and Kuckenburg, S. and Meier, Torsten and Koch, S.W. and Giessen, H. and Linden, S. and Kuhl, J.}}, issn = {{0370-1972}}, journal = {{physica status solidi (b)}}, keywords = {{tet_topic_polariton}}, number = {{1}}, pages = {{453--457}}, publisher = {{Wiley}}, title = {{{Nonlinear Polariton Pulse Propagation in Bulk Semiconductors}}}, doi = {{10.1002/1521-3951(200009)221:1<453::aid-pssb453>3.0.co;2-q}}, volume = {{221}}, year = {{2002}}, } @article{43294, abstract = {{The quantum dynamics of an ensemble of interacting electrons in an array of random scatterers is treated using a numerical approach for the calculation of average values of quantum operators and time correlation functions in the Wigner representation. The Fourier transform of the product of matrix elements of the dynamic propagators obeys an integral Wigner-Liouville-type equation. Initial conditions for this equation are given by the Fourier transform of the Wiener path-integral representation of the matrix elements of the propagators at the chosen initial times. This approach combines both molecular dynamics and Monte Carlo methods and computes numerical traces and spectra of the relevant dynamical quantities such as momentum-momentum correlation functions and spatial dispersions. Considering, as an application, a system with fixed scatterers, the results clearly demonstrate that the many-particle interaction between the electrons leads to an enhancement of the conductivity and spatial dispersion compared to the noninteracting case.}}, author = {{Meier, Torsten and Filinov, V. and Thomas, P. and Varga, I. and Bonitz, M. and Fortov, V. and Koch, S.W.}}, journal = {{Physical Review B}}, number = {{16}}, publisher = {{American Physical Society}}, title = {{{Interacting electrons in a one-dimensional random array of scatterers: A quantum dynamics and Monte Carlo study}}}, doi = {{10.1103/PhysRevB.65.165124}}, volume = {{65}}, year = {{2002}}, } @article{43295, abstract = {{The influence of coherent photoexcited excitons on the absorption spectra and the Four Wave Mixing response of ZnSe/ZnMgSSe quantum wells is investigated for various polarization configurations. For purely resonant excitation at the heavy-hole-exciton a blue shift and an increasing homogeneous line width of the exciton absorption peak is found. The clear and stable blue shift shows a linear dependence on excitation fluence both in experiment and theory with different slopes for the different pump and probe polarization configurations. The equivalence of pump and probe, and Four Wave Mixing results is shown experimentally.}}, author = {{Meier, Torsten and Wachter, S. and Maute, M. and Kalt, H. and Galbraith, I. and Sieh, C. and Koch, S.W.}}, journal = {{Physica B: Condensed Matter}}, number = {{1-4}}, pages = {{309--313}}, publisher = {{North-Holland}}, title = {{{Excitation induced shift and broadening of the exciton resonance}}}, doi = {{10.1016/S0921-4526(01)01400-4}}, volume = {{314}}, year = {{2002}}, } @article{43292, abstract = {{Physicists have realized during the last two decades that the physical properties of many condensed-matter systems are often best described in terms of lumps of charge, known as quasiparticles, rather than by electrons and ions. In a crystal under equlibrium conditions, for example, the mutual repulsion of the electrons leads to a cloud of positive charge surrounding each individual electron. This "dressing" of electrons leads to charge screening. In other words, a test charge placed far from an electron will feel the influence of a new entity with a smaller charge, rather than the charge on the "bare" electron.}}, author = {{Meier, Torsten and Koch, S.W.}}, journal = {{Physics World}}, number = {{2}}, pages = {{24--25}}, publisher = {{IOP Publishing}}, title = {{{Particles get all dressed up}}}, doi = {{10.1088/2058-7058/15/2/36}}, volume = {{15}}, year = {{2002}}, } @article{43291, abstract = {{On the basis of a tight-binding model for a strongly disordered semiconductor with correlated conduction- and valence-band disorder a coherent dynamical intraband effect is analyzed. For systems that are excited by two specially designed ultrashort light-pulse sequences delayed by τ relatively to each other echolike phenomena are predicted to occur. In addition to the interband photon echo which shows up at exactly t=2τ relative to the first pulse, the system responds with two spontaneous intraband current pulses preceding and following the appearance of the photon echo. The temporal splitting depends on the electron-hole mass ratio. Calculating the population relaxation rate due to Coulomb scattering, it is concluded that the predicted new dynamical effect should be experimentally observable in an interacting and strongly disordered system, such as the Quantum Coulomb Glass.}}, author = {{Meier, Torsten and Schlichenmaier, C. and Varga, I. and Thomas, P. and Koch, S.W.}}, journal = {{Physical Review B}}, number = {{8}}, publisher = {{American Physical Society}}, title = {{{Optically induced coherent intraband dynamics in disordered semiconductors}}}, doi = {{10.1103/PhysRevB.65.085306}}, volume = {{65}}, year = {{2002}}, } @inproceedings{44127, abstract = {{A microscopic theory for optical semiconductor nonlinearities systematically including Coulomb correlation effects is able to explain AC Stark shifts measured with all possible pump/probe circular polarizations and gives evidence for a 3-level-atom-like intervalence band coherence.}}, author = {{Meier, Torsten and Gibbs, H.M. and Khitrova, G. and Ell, C. and Binder, R. and Hoyer, W. and Kira, M. and Koch, S.W. and Sieh, C.}}, booktitle = {{Nonlinear Optics: Materials, Fundamentals and Applications}}, isbn = {{1-55752-721-0}}, location = {{Wailea, Maui, Hawaii United States}}, publisher = {{Optical Society of America}}, title = {{{Higher-Order Correlations and Semiconductor Optical Nonlinearities}}}, doi = {{10.1364/NLO.2002.WA1}}, year = {{2002}}, } @article{43293, abstract = {{We present a derivation of Förster coupling between two quantum dots by solving the equation of motion for the material excitation simultaneously with Maxwells equations. This allows us to identify the Förster process with the short-range contribution of the coupling that is mediated by the total electric field. The dependence of the coupling on the distance R of the dots is ∝ R—3, i.e. the rates follow the well-known R—6 behaviour. For distances between the sites longer than a quarter of the wavelength of light there is a cross-over to coupling due to the retarded light field, which is ∝ R—1, i.e. the rates are ∝ R—2.}}, author = {{Meier, Torsten and Thomas, P. and Möller, M. and Eichmann, R. and Stroucken, T. and Knorr, A.}}, journal = {{physica status solidi (b)}}, number = {{1}}, pages = {{25--29}}, publisher = {{WILEY‐VCH Verlag Berlin GmbH}}, title = {{{Microscopic Foundation of the Förster Excitonic Energy Transfer Process}}}, doi = {{10.1002/1521-3951(200203)230:1<25::AID-PSSB25>3.0.CO;2-8}}, volume = {{230}}, year = {{2002}}, }