@inproceedings{4179, abstract = {{We numerically investigate Whispering Gallery Modes (WGM) in a subwavelength microdisk resonator [1] embedded in an uniaxial anisotropic liquid crystal environment. It is shown that the WGMs have anticrossing behavior when modes of different radial mode order M or azimuthal order N approach each other spectrally. }}, author = {{Förstner, Jens and Declair, S. and Meier, Cedrik and Meier, Torsten}}, booktitle = {{Theoretical and Computational Nanophotonics Tacona-Photonics}}, keywords = {{tet_topic_microdisk}}, location = {{Tacona}}, number = {{1}}, pages = {{60--62}}, title = {{{Anticrossing of Whispering Gallery Modes in Microdisk Resonators Embedded in a Liquid Crystal}}}, doi = {{10.1063/1.3253921}}, volume = {{1176}}, year = {{2009}}, } @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}}, } @inproceedings{4184, abstract = {{We have experimentally investigated injection currents generated by all-optical excitation of GaAs/AlGaAs quantum wells excited with 130 fs optical pulses. The currents have been detected via free-space THz experiments at room temperature. Our experiments prove that Coulomb effects strongly influence injection currents. This becomes most prominently visible when exciting light-hole exciton transitions. At this photon energy we observe a pronounced phase shift of the current transients which is due to oppositely oriented heavy-hole and light-hole type contributions. We are currently developing a microscopic theory based on a 14×14 k.p model in combination with the semiconductor Bloch equations to describe the observed features quantitatively. The combined theoretical and experimental approach will allow us to analyze the influence of the bandstructure and interaction effects on the injection current amplitude and current dynamics.}}, author = {{Bieler, M. and Pierz, K. and Siegner, U. and Dawson, P. and Duc, H. T. and Förstner, Jens and Meier, Torsten}}, booktitle = {{Ultrafast Phenomena in Semiconductors and Nanostructure Materials XIII}}, editor = {{Tsen, Kong-Thon and Song, Jin-Joo and Betz, Markus and Elezzabi, Abdulhakem Y.}}, keywords = {{tet_topic_qw}}, location = {{San Jose (California / USA)}}, pages = {{721404--721404--13}}, publisher = {{SPIE}}, title = {{{Generation of injection currents in (110)-oriented GaAs quantum wells: experimental observation and development of a microscopic theory}}}, doi = {{10.1117/12.811841}}, volume = {{7214}}, year = {{2009}}, } @inproceedings{44104, abstract = {{The paper presents a theoretical analysis of the nonlinear THz response from the internal transitions of coherent and incoherent excitons based on the formulated microscopic THz theory. Moreover, the response of unexcited semiconductors to extremely intense THz fields is investigated .The intersubband transitions of optically excited quantum wells using linear THz spectroscopy is also studied. The computed differential transmission shows a characteristic Fano-like line shape of the intersubband resonance. The pure intersubband contribution is given by a simple Lorentzian. Applying the microscopic theory, the Fano features of the total response can be attributed to the phase-sensitive superposition of the intersubband transitions and the ponderomotive contribution. These results are in excellent agreement with recent experiments.}}, author = {{Meier, Torsten and Koch, S.W. and Kira, M. and Steiner, J.T. and Golde, D.}}, booktitle = {{ CLEO/Europe - EQEC 2009 - European Conference on Lasers and Electro-Optics and the European Quantum Electronics Conference}}, isbn = {{978-1-4244-4079-5}}, location = {{Munich, Germany}}, publisher = {{IEEE}}, title = {{{Microscopic theory of the linear and nonlinear Terahertz response of semiconductors}}}, doi = {{10.1109/CLEOE-EQEC.2009.5192555}}, year = {{2009}}, } @inproceedings{44105, abstract = {{By combining coherent control schemes and photoelectron spectroscopy it is possible to generate ultrafast current pulses at surfaces and in solids and to detect their decay directly in momentum space with femtosecond time resolution.}}, author = {{Meier, Torsten and Koch, S.W. and Rohleder, M. and Gudde, J. and Hofer, U.}}, booktitle = {{Conference on Lasers and Electro-Optics and 2009 Conference on Quantum electronics and Laser Science Conference}}, issn = {{2160-9004}}, location = {{Baltimore, MD, USA}}, pages = {{1--2}}, publisher = {{IEEE}}, title = {{{Ultrafast coherent photoelectron emission effects and their application for time-domain studies of current transport}}}, doi = {{10.1364/IQEC.2009.IThI5}}, year = {{2009}}, } @article{24983, abstract = {{The recently developed two-dimensional Fourier-Transform-Spectroscopy (2DFTS) in the optical regime has been established as an elegant experiment, which has manifold of applications in the investigation of semiconductor nanostructures. Here we focus on the real and imaginary part 2DFT spectra. As predicted recently, using rephasing and non-rephasing modes, we are able to determine the homogeneous and inhomogeneous broadenings of coupled excitonic resonances even for weak disorder where photon-echo data are not useful. Computed real and imaginary parts of the 2DFTS for rephasing and non-rephasing modes are compared with experimental data of a GaAs quantum well. It is demonstrated, that phase sensitive data for the rephasing and non-rephasing modes are able to accurately provide the disorder induced broadening in a complex coupled system for each transition separately. }}, author = {{Kuznetsova, Irina and Thomas, Peter and Meier, Torsten and Zhang, Tianhao and Cundiff, Steven T.}}, issn = {{1610-1634}}, journal = {{physica status solidi (c)}}, number = {{2}}, pages = {{445--448}}, publisher = {{WILEY‐VCH Verlag}}, title = {{{Determination of homogeneous and inhomogeneous broadenings of quantum-well excitons by 2DFTS: An experiment-theory comparison}}}, doi = {{10.1002/pssc.200880302}}, volume = {{6}}, year = {{2009}}, } @article{24982, abstract = {{A microscopic analysis of the emitted radiation of a semiconductor nanostructure after excitation with an extremely intense ultrashort laser pulse is presented. It is shown that the extreme nonlinear optical response is not sufficiently described by pure interband transitions but one has to include intraband effects as well. Numerical solutions of extended Bloch equations that include the coupled inter- and intraband dynamics are presented. For large excitation intensities, the intraband effects strongly modify the polarization dynamics and lead to a strong enhancement of high-harmonic generation compared to pure interband dynamics.}}, author = {{Golde, Daniel and Meier, Torsten and Koch, Stephan W.}}, issn = {{1610-1634}}, journal = {{physica status solidi (c)}}, number = {{2}}, pages = {{420--423}}, publisher = {{WILEY‐VCH Verlag}}, title = {{{Microscopic analysis of high-harmonic generation in semiconductor nanostructures}}}, doi = {{10.1002/pssc.200880309}}, volume = {{6}}, year = {{2009}}, } @article{44106, author = {{Meier, Torsten and Michler, Peter}}, journal = {{physica status solidi c}}, number = {{2}}, pages = {{379--380}}, publisher = {{WILEY‐VCH Verlag}}, title = {{{Preface}}}, doi = {{10.1002/pssc.200960045}}, volume = {{6}}, year = {{2009}}, } @inproceedings{44068, abstract = {{The band structure and wave functions of GaAs quantum wells are computed via k.p band structure theory including anisotropy and spin splitting. Using these results, the process of generating photocurrents by optical excitation is analyzed. Depending on the symmetry of the material, the direction of the laser beam, and the polarization direction of the light field/s, one can coherently generate charge and/or spin photocurrents on ultrashort time scales. The direction, the strength, and the dynamics of these photocurrents are computed and discussed.}}, author = {{Meier, Torsten and Duc, Huynh Thanh and Foerstner, Jens}}, booktitle = {{DPG Spring meeting 2009}}, issn = {{0420-0195}}, location = {{Dresden, Germany}}, number = {{5}}, title = {{{Photo-and spin current generation and dynamics in semiconductor nanostructures}}}, volume = {{44}}, year = {{2009}}, } @inproceedings{4181, abstract = {{We experimentally and theoretically investigate microdisk resonators with embedded quantum dots immersed in a liquid crystal in its nematic phase, showing the tunabililty of the photonic modes via external parameters like temperature or electric field.}}, author = {{Förstner, Jens and Meier, Cedrik and Piegdon, Karoline and Declair, Stefan and Hoischen, Andreas and Urbanski, Mark and Meier, Torsten and Kitzerow, Heinz-Siegfried}}, booktitle = {{Advances in Optical Sciences Congress}}, isbn = {{9781557528735}}, keywords = {{tet_topic_microdisk}}, location = {{Honolulu, Hawaii United States}}, publisher = {{OSA Technical Digest (CD) (Optical Society of America, 2009), paper NTuC2}}, title = {{{Coupling Dynamics of Quantum Dots in a Liquid-Crystal-Tunable Microdisk Resonator}}}, doi = {{10.1364/nlo.2009.ntuc2}}, year = {{2009}}, } @inproceedings{44112, abstract = {{Homogeneous and inhomogeneous broadening of heavy- and light-hole excitons in semiconductor quantum wells are measured along with the excitation dependence of both broadenings. Isolation of disorder-induced broadening is possible with spectra in different coherent pathways.}}, author = {{Meier, Torsten and Zhang, Tianhao and Bristow, Alan D. and Dai, Xingcan and Kuznetsova, Irina and Thomas, P. and Cundiff, S.T.}}, booktitle = {{Quantum Electronics and Laser Science Conference}}, isbn = {{978-1-55752-859-9}}, location = {{San Jose, California United States}}, publisher = {{Optical Society of America}}, title = {{{Direct determination of exciton homogeneous and inhomogeneous linewidths in semiconductor quantum wells with two-dimensional fourier transform spectroscopy}}}, year = {{2008}}, } @inproceedings{44110, author = {{Meier, Torsten and Duc, Huynh Thanh and Koch, S.W. and Pasenow, B.}}, booktitle = {{72nd annual meeting and DPG spring meeting of the Condensed Matter Section and the Divisions}}, location = {{Berlin, Germany}}, title = {{{Intensity dependence of charge and spin currents generated by ultrafast two-color photoexcitation of semiconductor quantum wells}}}, volume = {{43}}, year = {{2008}}, } @inproceedings{44111, author = {{Meier, Torsten and Koch, S.W. and Pasenow, B.}}, booktitle = {{72nd annual meeting and DPG spring meeting of the Condensed Matter Section and the Divisions}}, location = {{Berlin, Germany}}, title = {{{Influence of heavy-hole light-hole band mixing on the strength of optically generated spin-currents in III-V semiconductor quantum wells}}}, volume = {{42}}, year = {{2008}}, } @article{23483, abstract = {{The emitted radiation from semiconductor nanostructures due to the excitation with intense ultrashort optical laser pulses is analyzed. Semiconductor Bloch equations that consistently describe the coupled light-field-induced interband and intraband dynamics are solved numerically. It is demonstrated that the intraband dynamics considerably influences the light emission in the regime of extreme nonlinear optics. In particular, the intraband acceleration significantly modifies the dynamics of the interband polarization which results in a strong enhancement of high-harmonic generation.}}, author = {{Golde, D. and Meier, Torsten and Koch, S. W.}}, issn = {{1098-0121}}, journal = {{Physical Review B}}, number = {{7}}, title = {{{High harmonics generated in semiconductor nanostructures by the coupled dynamics of optical inter- and intraband excitations}}}, doi = {{10.1103/physrevb.77.075330}}, volume = {{77}}, year = {{2008}}, } @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}}, } @inproceedings{24981, author = {{Güdde, J. and Rohleder, M. and Meier, Torsten and Koch, S.W. and Höfer, U.}}, booktitle = {{Frontiers in Optics 2008/Laser Science XXIV/Plasmonics and Metamaterials/Optical Fabrication and Testing}}, isbn = {{978-1-55752-861-2}}, location = {{Rochester, New York United States}}, title = {{{Generation and Time-Resolved Detection of Coherently Controlled Electric Currents at Surfaces}}}, doi = {{10.1364/fio.2008.fmi3}}, year = {{2008}}, } @inbook{23485, abstract = {{The ultrafast dynamics of optical excitations in semiconductors and semiconductor nanostructures can be computed on a microscopic theoretical basis using the semiconductor Bloch equations. This set of equations allows one to nonperturbatively evaluate light-field-induced intraband and interband excitations and is also well suited for the analysis of many-body effects such as excitonic resonances and carrier-carrier and carrier-phonon scattering processes. In this article we start with a description of an experimental observation of coherent spin photocurrents, then we briefly introduce the theoretical approach and review some results of our theory concerning the microscopic description of the ultrafast coherent optical generation and the temporal decay of charge and spin currents in semiconductor nanostructures. The computed transients show an enhanced damping of the spin current relative to the charge current as a consequence of Coulomb scattering between carriers with opposite spin. The influence of quantum kinetic memory effects on the dynamics of the photocurrents is analyzed by evaluating the scattering terms beyond the Markov approximation.}}, author = {{Meier, Torsten and Duc, Huynh Thanh and Vu, Quang Tuyen and Pasenow, Bernhard and Hübner, Jens and Chatteryee, Sangam and Rühle, Wolfgang W. and Haug, Hartmut and Koch, Stephan W.}}, booktitle = {{Advances in Solid State Physics}}, isbn = {{978-3-540-38234-8}}, pages = {{199--210}}, publisher = {{Springer}}, title = {{{Ultrafast Dynamics of Optically-Induced Charge and Spin Currents in Semiconductors}}}, doi = {{10.1007/978-3-540-38235-5_15}}, year = {{2008}}, } @inbook{24979, abstract = {{The ultrafast dynamics of optical excitations in semiconductors and semiconductor nanostructures can be computed on a microscopic theoretical basis using the semiconductor Bloch equations. This set of equations allows one to nonperturbatively evaluate light-field-induced intraband and interband excitations and is also well suited for the analysis of many-body effects such as excitonic resonances and carrier-carrier and carrier-phonon scattering processes. In this article we start with a description of an experimental observation of coherent spin photocurrents, then we briefly introduce the theoretical approach and review some results of our theory concerning the microscopic description of the ultrafast coherent optical generation and the temporal decay of charge and spin currents in semiconductor nanostructures. The computed transients show an enhanced damping of the spin current relative to the charge current as a consequence of Coulomb scattering between carriers with opposite spin. The influence of quantum kinetic memory effects on the dynamics of the photocurrents is analyzed by evaluating the scattering terms beyond the Markov approximation.}}, author = {{Meier, Torsten and Duc, Huynh Thanh and Vu, Quang Tuyen and Pasenow, Bernhard and Hübner, Jens and Chatteryee, Sangam and Rühle, Wolfgang W. and Haug, Hartmut and Koch, Stephan W.}}, booktitle = {{Advances in Solid State Physics}}, isbn = {{978-3-540-38234-8}}, pages = {{199--210}}, publisher = {{Springer}}, title = {{{Ultrafast Dynamics of Optically-Induced Charge and Spin Currents in Semiconductors}}}, doi = {{10.1007/978-3-540-38235-5_15}}, year = {{2008}}, } @article{40411, author = {{Pasenow, B. and Duc, H.T. and Meier, Torsten and Koch, S.W.}}, issn = {{0038-1098}}, journal = {{Solid State Communications}}, keywords = {{Materials Chemistry, Condensed Matter Physics, General Chemistry}}, number = {{1-2}}, pages = {{61--65}}, publisher = {{Elsevier BV}}, title = {{{Rabi flopping of charge and spin currents generated by ultrafast two-colour photoexcitation of semiconductor quantum wells}}}, doi = {{10.1016/j.ssc.2007.09.029}}, volume = {{145}}, year = {{2008}}, }