@inproceedings{3965, abstract = {{We design the geometrical shape of plasmonic nanostructures to achieve field patterns with desired properties. For this, we combine Maxwell simulations and automatic optimization techniques. By allowing variations of the geometrical shape, which can be based on either boxes or arbitrary polygons, we maximize the desired objective.}}, author = {{Hildebrandt, Andre and Reichelt, Matthias and Meier, Torsten and Förstner, Jens}}, keywords = {{tet_topic_optical antenna, tet_topic_plasmonics}}, location = {{Bad Honnef}}, number = {{59}}, publisher = {{AIP AIP Conference Proceedings 1475}}, title = {{{Optimization of the intensity enhancement in plasmonic nanoantennas}}}, doi = {{10.1063/1.4750095}}, year = {{2012}}, } @inproceedings{44062, abstract = {{Optical two-dimensional Fourier transform spectroscopy has been used to study the properties of semiconductor nanostructures in four-wave-mixing like experiments. Applying a phenomenological level model, we numerically and analytically analyze the main features of excitonic and biexcitonic contributions in a semiconductor quantum well by solving the optical Bloch equations. The method is extended to three-dimensional Fourier transform spectroscopy to investigate a recent experiment.}}, author = {{Meier, Torsten and Wiebeler, Christian and Reichelt, Matthias}}, booktitle = {{ 75. Annual meeting of the DPG and combined DPG Spring meeting }}, issn = {{0420-0195}}, location = {{Dresden, Germany}}, number = {{1}}, title = {{{Analysis of multidimensional Fourier transform spectroscopy for semiconductors with a phenomenological level model}}}, volume = {{46}}, year = {{2011}}, } @inproceedings{44061, abstract = {{If a two-level system is excited with an intense light field of several times the Rabi frequency, the well-known Mollow triplets appear in the emitted radiation spectrum. We show that the pattern of the emission spectrum can be changed by using appropriately shaped laser pulses. The effect is also observable for a more realistic description of a semiconductor system.}}, author = {{Meier, Torsten and Reichelt, Matthias and Walther, Andrea}}, booktitle = {{75. Annual meeting of the DPG and combined DPG Spring meeting}}, issn = {{0420-0195}}, location = {{ Dresden, Germany}}, number = {{1}}, title = {{{Extreme nonlinear optics in semiconductors with shaped laser pulses}}}, volume = {{46}}, year = {{2011}}, } @article{43202, abstract = {{For numerous applications, the computation and provision of exact derivative information plays an important role for optimizing the considered system. This paper introduces the technique of algorithmic differentiation, a method to compute derivatives of arbitrary order within working precision. This derivative information will be combined with a calculus-based optimization algorithm to optimize a non-trivially shaped laser pulse which coherently steers the electron dynamics in a semiconductor quantum wire. Numerical results illustrating the cost for the derivative computation and the optimization process are presented and discussed.}}, author = {{Meier, Torsten and Reichelt, Matthias and Walther, A.}}, journal = {{Photonics and Nanostructures - Fundamentals and Applications}}, number = {{4}}, pages = {{328--336}}, publisher = {{Elsevier}}, title = {{{Calculus-based optimization of the electron dynamics in nanostructures}}}, doi = {{10.1016/j.photonics.2011.03.006}}, volume = {{9}}, year = {{2011}}, } @inproceedings{44065, abstract = {{The behavior of waveguide plasmon polaritons is studied employing ultrafast coherent control like schemes for a gold lattice coupled to a photonic waveguide for the structure. Different models to describe the third-harmonic generation are presented and the resulting equations are solved numerically. The calculations are compared to recent experimental data and show good agreement for the most prominent features in the time-integrated third order intensity.}}, author = {{Meier, Torsten and Podzimski, Reinold and Reichelt, Matthias and Utikal, Tobias and Giessen, Harald}}, booktitle = {{DPG Spring meeting 2010}}, issn = {{0420-0195}}, location = {{Regensburg, Germany}}, number = {{3}}, title = {{{Controlling the third-harmonic generation in a metallic photonic crystal coupled to a waveguide}}}, volume = {{45}}, year = {{2010}}, } @inproceedings{44069, abstract = {{Recently it has been shown experimentally that it is possible to coherently control nano-optical excitations by using sophisticated shaped laser pulses. In this work a similar technique is used to theoretically investigate a hybrid nanostructure which consists of a metal aperture and a quantum wire. It is shown that one can concentrate the optically excited electron density at an arbitrary position due to wave packet dynamics by chosing particular frequency components and phases of the chirped laser pulse. The optimization process is performed with a genetic algorithm which is linked to a 3D-FDTD solver.}}, author = {{Meier, Torsten and Reichelt, Matthias}}, booktitle = {{DPG Spring meeting 2009}}, issn = {{0420-0195}}, location = {{Dresden, Germany}}, number = {{5}}, title = {{{Coherent control in hybrid metal-semiconductor nanostructures}}}, volume = {{44}}, year = {{2009}}, } @article{23481, abstract = {{A one-dimensional semiconductor nanostructure is locally excited through a metal aperture. It is shown that the electron density can be coherently localized at desired spatial and temporal positions by using nontrivially shaped laser pulses. To obtain the optimized laser field, Bloch equations for a tight-binding model system are solved together with a genetic pulse-shaping algorithm. Full three-dimensional finite-difference time-domain (FDTD) simulations of the Maxwell–Bloch equations confirm the predicted coherent spatiotemporal control.}}, author = {{Reichelt, Matthias and Meier, Torsten}}, issn = {{0146-9592}}, journal = {{Optics Letters}}, number = {{19}}, pages = {{2900--2902}}, title = {{{Shaping the spatiotemporal dynamics of the electron density in a hybrid metal-semiconductor nanostructure}}}, doi = {{10.1364/ol.34.002900}}, volume = {{34}}, year = {{2009}}, } @inbook{44109, author = {{Meier, Torsten and Pasenow, B. and Reichelt, Matthias and Stroucken, T.}}, booktitle = {{Nanophotonic Materials: Photonic Crystals, Plasmonics, and Metamaterials}}, editor = {{Busch, Kurt and Kitzerow, H.-S. and Wehrspohn, Ralf B.}}, isbn = {{9783527408580 }}, pages = {{15--38}}, publisher = {{Wiley‐VCH Verlag GmbH & Co. KGaA}}, title = {{{Microscopic Analysis of the Optical and Electronic Properties of Semiconductor Photonic-Crystal Structures}}}, doi = {{10.1002/9783527621880.ch2}}, year = {{2008}}, } @article{43268, abstract = {{The combination of dielectric photonic crystals and semiconductor nanostructures makes it possible to design many important aspects of the optoelectronic system response. A spatially-varying dielectric environment induces modifications of the transversal and the longitudinal components of the electromagnetic field which have to be included in the self-consistent microscopic analysis of the optical properties of hybrid semiconductor photonic-crystal structures. In this paper, the development of a semiclassical microscopic theory is reviewed. Whereas the classical electromagnetic field is described at the level of Maxwell's equations, a full many-body quantum theory is used for the interacting electronic excitations in the semiconductor material. Relevant examples of the numerical solutions of the resulting Maxwell semiconductor Bloch equations are presented showing, e.g., characteristic modifications of excitonic absorption spectra, the spatio-temporal dynamics of electronic wave packets, as well as an increase of the optical gain in properly designed device geometries.}}, author = {{Pasenow, B. and Reichelt, Matthias and Stroucken, T. and Meier, Torsten and Koch, S.W.}}, journal = {{physica status solidi (a)}}, number = {{11}}, pages = {{3600--3617}}, publisher = {{WILEY‐VCH Verlag}}, title = {{{Microscopic analysis of the optical and electronic properties of semiconductor photonic‐crystal structures}}}, doi = {{10.1002/pssa.200776403}}, volume = {{204}}, year = {{2007}}, } @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}}, } @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}}, } @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{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}}, } @article{23498, abstract = {{The ultrafast dynamics of photoexcitations at silicon surfaces is investigated using a surface-sensitive purely optical technique. In the experiments, the diffracted second harmonic generated by sequences of ultrashort laser pulses is detected as a function of the time delay between the pulses. It is demonstrated that this five-wave-mixing technique can be used to measure the temporal evolution of the optical polarization and the photoexcited populations at the surface. The experimental results can be reproduced by numerical solutions of optical Bloch equations. The theoretical analysis allows one to investigate which dephasing times and relaxation processes are compatible with experiment. Furthermore, it is outlined how one can describe optical nonlinearities at surfaces using a microscopic theory within the framework of semiconductor Bloch equations.}}, author = {{Meier, Torsten and Reichelt, Matthias and Koch, S W and Höfer, U}}, issn = {{0953-8984}}, journal = {{Journal of Physics: Condensed Matter}}, number = {{8}}, pages = {{S221--S244}}, title = {{{Femtosecond time-resolved five-wave mixing at silicon surfaces}}}, doi = {{10.1088/0953-8984/17/8/003}}, volume = {{17}}, year = {{2005}}, } @article{23499, abstract = {{The ultrafast dynamics of photoexcitations at silicon surfaces is investigated using a surface-sensitive purely optical technique. In the experiments, the diffracted second harmonic generated by sequences of ultrashort laser pulses is detected as a function of the time delay between the pulses. It is demonstrated that this five-wave-mixing technique can be used to measure the temporal evolution of the optical polarization and the photoexcited populations at the surface. The experimental results can be reproduced by numerical solutions of optical Bloch equations. The theoretical analysis allows one to investigate which dephasing times and relaxation processes are compatible with experiment. Furthermore, it is outlined how one can describe optical nonlinearities at surfaces using a microscopic theory within the framework of semiconductor Bloch equations.}}, author = {{Meier, Torsten and Reichelt, Matthias and Koch, S W and Höfer, U}}, issn = {{0953-8984}}, journal = {{Journal of Physics: Condensed Matter}}, number = {{8}}, pages = {{S221--S244}}, title = {{{Femtosecond time-resolved five-wave mixing at silicon surfaces}}}, doi = {{10.1088/0953-8984/17/8/003}}, volume = {{17}}, year = {{2005}}, } @inproceedings{44297, author = {{Meier, Torsten and Reichelt, Matthias and Pasenow, B. and Stroucken, T. and Koch, S.W.}}, booktitle = {{2005 annual conference of the German Physical Society (DPG) during the World year of physics}}, location = {{Berlin, Germany}}, title = {{{Optical properties of semiconductor photonic-crystal structures: spatially-inhomogeneous excitonic resonances and optical gain}}}, volume = {{40}}, year = {{2005}}, } @article{23503, author = {{Oszwałdowski, R. and Reichelt, Matthias and Meier, Torsten and Koch, S. W. and Rohlfing, Michael}}, issn = {{1098-0121}}, journal = {{Physical Review B}}, number = {{23}}, title = {{{Nonlinear optical response of the Si ( 111 ) − ( 2 × 1 ) surface exciton: Influence of biexciton many-body correlations}}}, doi = {{10.1103/physrevb.71.235324}}, volume = {{71}}, year = {{2005}}, } @article{23512, abstract = {{The optically induced electron dynamics at a Si(001) surface is studied using a five-wave-mixing setup which measures the diffracted second-harmonic intensity induced by three ultrashort (13 fs) laser pulses. Depending on the time ordering of the pulses, this technique is capable of monitoring the temporal evolution of photoexcited one- or two-photon coherences, or populations. For a particular pulse sequence, the experiments show a delayed rise and a decay of the diffracted signal intensity on time scales of 50 and 250 fs, respectively. This response can be described by optical Bloch equations by including rapid scattering of the photoexcited carriers in the D(down)band of Si(001).}}, author = {{Voelkmann, C. and Reichelt, Matthias and Meier, Torsten and Koch, S. W. and Höfer, U.}}, issn = {{0031-9007}}, journal = {{Physical Review Letters}}, number = {{12}}, title = {{{Five-Wave-Mixing Spectroscopy of Ultrafast Electron Dynamics at a Si(001) Surface}}}, doi = {{10.1103/physrevlett.92.127405}}, volume = {{92}}, year = {{2004}}, }