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PRODID:-//GRK 2905 - Ultrafast Nanoscopy - ECPv6.6.4.1//NONSGML v1.0//EN
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X-ORIGINAL-URL:https://grk2905.de
X-WR-CALDESC:Events for GRK 2905 - Ultrafast Nanoscopy
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BEGIN:VEVENT
DTSTART;TZID=Europe/Berlin:20250922T100000
DTEND;TZID=Europe/Berlin:20250922T110000
DTSTAMP:20260429T210637
CREATED:20250918T094447Z
LAST-MODIFIED:20260326T162416Z
UID:1795-1758535200-1758538800@grk2905.de
SUMMARY:RTG Seminar:Dr. Carolin Gold
DESCRIPTION:From microscopic to macroscopic phenomena:Bridging length scales in two- dimensional quantum materials \n\n\n\nColumbia University \n\n\n\nTwo-dimensional quantum materials have driven a revolution in condensed matter physics through the realization of a large variety of exotic quantum phenomena\, ranging from strong correlations and quantum magnetism to topological states. At the core of this revolution is the unique tunability of the quantum phases emergent at the macroscopic scale through variations in the microscopic roperties of the material. Despite decades of intensive theoretical and experimental endeavors\, bridging these two length scales has remained a major challenge\, leaving numerous questions nanswered.In this talk\, we demonstrate how atomic force microscopy (AFM) can be used not only to (i) probe quantum electronic states across multiple length scales\, but also to (ii) locally control and engineer the interplay between microscopic and acroscopic properties in van der Waals materials. Using the AFM tip as a mechanical actuator we bend narrow van der Waals ribbons\, realizing (moiré) heterostructures with engineered twist angle and strain gradients. Combining these structures with low-temperature conductive AFM imaging not only reveals their unique electronic properties\, but also opens exciting avenues for studying the interplay between microscopic and macroscopic length scales through versatile and novel AFM techniques. \n\n\n\n \n\n\n\n \n\n\n\n \n\n\n\nVenue: RUN Auditorium
URL:https://grk2905.de/event/grk-seminardr-caroline-gold/
CATEGORIES:Seminar
ATTACH;FMTTYPE=image/jpeg:https://grk2905.de/wp-content/uploads/2025/09/Gold.jpeg
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Berlin:20250729T140000
DTEND;TZID=Europe/Berlin:20250729T170000
DTSTAMP:20260429T210637
CREATED:20250630T092030Z
LAST-MODIFIED:20260326T162357Z
UID:1712-1753797600-1753808400@grk2905.de
SUMMARY:RTG seminar:Martin Švec
DESCRIPTION:Photon-induced processes at single molecules in SPM nanocavitiesInstitute of PhysicsCzech Academy of SciencesPraha 6\,Czech Republic \n\n\n\n \n\n\n\n \n\n\n\nExploration of isolated chromophores – optically active molecules – often reveals stunningly complex internal dynamics of excitations and transitions between electronic configurations\, influenced by coupling to vibrational levels and reorganization of local environments. One of the promising tools for studying the photophysics of individual molecules with nanometer resolution is optical spectroscopy that employs plasmonic\, atomically sharp tips in Scanning Probe Microscopy (SPM)\, which overcomes the fundamental spatial resolution limits of visible and infrared light. This methodology enables measurements that correlate electronic structure and atomic arrangement with various photon spectroscopies – e.g.\, fluorescence\, absorption\, and Raman scattering – as a function of applied electric field and measurement geometry. In this lecture\, I will present our experiments with photon spectroscopies using SPM\, focusing in particular on photon absorption-induced phenomena such as photoluminescence\, and photon-induced current generation\, through which we achieved a direct visual discrimination among the components of a multiconfigurational state of an open-shell chromophore. \n\n\n\nVenue: RUN 0\,35
URL:https://grk2905.de/event/grk-seminarmartin-svec/
CATEGORIES:Seminar
ATTACH;FMTTYPE=image/png:https://grk2905.de/wp-content/uploads/2025/06/Screenshot-2025-06-30-111801.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Berlin:20250723T140000
DTEND;TZID=Europe/Berlin:20250723T160000
DTSTAMP:20260429T210637
CREATED:20250630T091602Z
LAST-MODIFIED:20260326T162327Z
UID:1705-1753279200-1753286400@grk2905.de
SUMMARY:RTG seminar: Patrick Rupprecht
DESCRIPTION:Shedding light on ultrafast quantum dynamics with attosecond spectroscopyFeodor Lynen Postdoctoral FellowLeone & Neumark GroupsLawrence Berkeley National LaboratoryUSA \n\n\n\n \n\n\n\nThe physics and chemistry of matter is determined by the interaction of electrons and nuclei on ultrafast timescales down to the attosecond (10-18 s) regime. In this seminar\, I will highlight how attosecond photon spectroscopy grants us a detailed look into the intricate quantum dynamics within atoms and molecules. Beyond precision metrology\, shortest laser pulses allow us to precisely manipulate the quantum interactions of electrons and nuclei. \n\n\n\nVenue: RUN auditorium
URL:https://grk2905.de/event/grk-seminar-patrick-rupprecht/
CATEGORIES:Seminar
ATTACH;FMTTYPE=image/png:https://grk2905.de/wp-content/uploads/2025/06/Screenshot-2025-06-30-111427-e1751274990233.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Berlin:20250718T100000
DTEND;TZID=Europe/Berlin:20250718T120000
DTSTAMP:20260429T210637
CREATED:20250630T100507Z
LAST-MODIFIED:20260326T162339Z
UID:1720-1752832800-1752840000@grk2905.de
SUMMARY:RTG Seminar: Ryo Shimano
DESCRIPTION:Higgs mode in superconductors studied by nonlinear terahertz spectroscopy Cryogenic Research Center & Department of Physics \n\n\n\nThe University of Tokio \n\n\n\ng \n\n\n\nRecent developments of experimental techniques based on ultrafast spectroscopy have enabled the access to low energy collective modes in quantum materials in a time-resolved manner. In particular\, the amplitude mode of the order parameter in superconductors\, called the Higgs amplitude mode\, has attracted a growing interest from the viewpoint of non-equilibrium dynamics in symmetry-broken ordered phases. In this presentation\, I will introduce the study of the Higgs mode and other collective modes in conventional and unconventional superconductors using various nonlinear terahertz spectroscopic schemes. \n\n\n\n \n\n\n\nVenue: RUN Auditorium
URL:https://grk2905.de/event/grk-seminar-ryo-shimano/
CATEGORIES:Seminar
ATTACH;FMTTYPE=image/jpeg:https://grk2905.de/wp-content/uploads/2025/06/Shimano-Ryo.jpg
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Berlin:20250515T151500
DTEND;TZID=Europe/Berlin:20250515T154500
DTSTAMP:20260429T210637
CREATED:20250410T093613Z
LAST-MODIFIED:20260326T162621Z
UID:1615-1747322100-1747323900@grk2905.de
SUMMARY:RTG seminar: Artur Slobodeniuk
DESCRIPTION:Intraband motion corrections to the spectrum of excitons in transition metal dichalcogenide monolayers \n\n\n\n \n\n\n\nDepartment of Condensed Matter Physics\, Faculty of Mathematics and Physics\, Charles University\, Prague\, Czech Republic \n\n\n\n \n\n\n\n \n\n\n\nTransition metal dichalcogenide (TMD) monolayers are among the most intriguing two-dimensional materials for optoelectronic applications due to their unique valley-dependent electronic properties. In particular\, the superposition of intravalley exciton states at the nonequivalent ±K points can be considered a qubit\, which has potential applications in various quantum technologies. The manipulation of such qubits for dark intravalley excitons using intense magnetic fields was demonstrated in 2019 [1]. Subsequently\, similar control over bright excitonic states using non-resonant circularly polarized light was both experimentally observed and theoretically explained [2\,3]. In the latter\, the theoretical analysis relied on the Semiconductor Bloch equations (SBE)\, where the dominant interband transition terms were considered. However\, as it turned out\, this approximation is valid for small intensities of applied optical pulses and needs to be reconsidered for more intense pulses. In this work\, we analyze the solutions of the SBE\, incorporating the previously neglected intraband term\, which governs electron dynamics within the separate bands. We develop a new perturbation technique and calculate corrections to the shifts of intravalley exciton energies in TMD monolayers [4]. The possibility of experimentally measuring these results is also discussed. \n\n\n\nReferences \n\n\n\n [1] M. R. Molas et al\, Phys. Rev. Lett. 123\, 096803 (2019) \n\n\n\n [2] A. O. Slobodeniuk et al\, npj 2D Mater. Appl. 7\, 17 (2023) \n\n\n\n [3] A. O. Slobodeniuk et al\, Phys. Rev. B 106\, 235304 (2022) \n\n\n\n[4] A. O. Slobodeniuk\, T. Novotny\, https://arxiv.org/abs/2501.06885 \n\n\n\n \n\n\n\nVenue: PHY 5.0.20
URL:https://grk2905.de/event/grk-seminar-artur-slobodeniuk/
CATEGORIES:Seminar
ATTACH;FMTTYPE=image/jpeg:https://grk2905.de/wp-content/uploads/2025/04/data-users-user-2451-people-artur-slobodeniuk-clip-w300-h375-e1744278366397.jpg
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Berlin:20250508T151500
DTEND;TZID=Europe/Berlin:20250508T160000
DTSTAMP:20260429T210637
CREATED:20250410T094457Z
LAST-MODIFIED:20260326T162647Z
UID:1620-1746717300-1746720000@grk2905.de
SUMMARY:RTG seminar:Prof. Dr. Götz Uhrig
DESCRIPTION:Concepts and applications in non-equilibrium physics \n\n\n\n \n\n\n\nTU Dortmund \n\n\n\n \n\n\n\nNon-equilibrium physics has become one of the thriving focal points in condensed matter physics. Pump-probe experiments are by now fairly common and further driving protocols attract more and more attention. We will discuss how periodic driving allows to cool a small quantum system by exploiting the commensurability of various oscillatory processes [1]. Interestingly\, the Lindblad damping of a highly excited state is crucial here. Turning to ordered magnetic systems\, it is common to describe their damping by Landau-Lifshitz-Gilbert equations. The question arises whether this phenomenological formalism is related to Lindblad damping. We will present such a conceptual link [2]. Finally\, we explicity consider how one can switch magnetic order efficiently by electromagnetic pulses. How strong do the pulses have to be [3]? What is the influence of relaxation? These question are relevant for processing data in magnetic storage devices. \n\n\n\n[1] Quantum coherence from commensurate driving with laser pulses and decay G.S. Uhrig; SciPost Phys. 8\, 040 (2020)[2] Landau-Lifshitz damping from Lindbladian dissipation in quantum magnets G.S. Uhrig; arXiv:2406.10613[3] Exchange enhanced switching by alternating fields in quantum antiferromagnets A. Khudoyberdiev\, G.S. Uhrig; Phys. Rev. B 111\, 064408 (2025) \n\n\n\nVenue: PHY 5.0.21
URL:https://grk2905.de/event/grk-seminarprof-dr-gotz-uhrig/
CATEGORIES:Seminar
ATTACH;FMTTYPE=image/jpeg:https://grk2905.de/wp-content/uploads/2025/04/uhrig_goetz_2024_10-scaled-e1744278379321.jpg
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Berlin:20250327T100000
DTEND;TZID=Europe/Berlin:20250327T110000
DTSTAMP:20260429T210637
CREATED:20250325T091915Z
LAST-MODIFIED:20260326T162706Z
UID:1594-1743069600-1743073200@grk2905.de
SUMMARY:RTG seminar:Dr. Jan Gerrit Horstmann
DESCRIPTION:Optical control of nonequilibrium phases: from hammers to tweezers: \n\n\n\nDepartment of Materials\,ETH Zurich \n\n\n\n \n\n\n\nUltrafast pump-probe spectroscopy has not only provided remarkable insights into electronic and structural dynamics on atomic length and femtosecond time scales but has also enabled the optical control of nonequilibrium states. Over the past decade\, a dominant trend in the field has been the shift from strong\, unselective optical stimuli towards the selective excitation of few key degrees of freedom—in other words\, from hammers to tweezers. This ap-proach promises more energy-efficient switching and access to entirely new states of matter.In this talk\, I will present three examples of optical control over nonequilibrium states with increasing selectivity. The spectrum ranges from laser-induced thermal quenching of a multiferroic domain pattern to the all-optical amplification of a key phonon mode in a van der Waals ferroelectric\, and finally to the ultrafast manipulation of metal-insulator nanotex-tures. Furthermore\, I will provide an outlook on a novel approach for the investigation and control of structural dynamics based on non-resonant excit-ation of phonons via transient Raman forces. \n\n\n\nVenue: RUN auditorium
URL:https://grk2905.de/event/grk-seminar-optical-control-of-nonequilibrium-phases-from-hammers-to-tweezers/
CATEGORIES:Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Berlin:20250326T133000
DTEND;TZID=Europe/Berlin:20250326T143000
DTSTAMP:20260429T210637
CREATED:20250325T103300Z
LAST-MODIFIED:20260326T162736Z
UID:1599-1742995800-1742999400@grk2905.de
SUMMARY:RTG seminar: Dr. David N Purschke
DESCRIPTION:Strong‐fields and photons in solids\, from classical to quantum light \n\n\n\n \n\n\n\nJoint Attosecond Science Laboratory\, University of Ottawa and NationalResearch Council of Canada \n\n\n\n \n\n\n\n \n\n\n\nAt the surface\, strong‐field physics and quantum optics seem to operate in disparate regimes of light‐matter interaction. Nevertheless\, the growing field of attosecond quantum opticsis beginning to bridge this gap\, with the solid state providing an ideal platform of study [1]. I will discuss two experiments at this intersection: in the first\, we see how a photon picture emerges from a laser‐dressed crystal using classical light [2]. In the second\, we begin to study field‐driven processes with emerging non‐classical and intense sources known as brightsqueezed vacuum [3]. \n\n\n\n[1] L. Cruze‐Rodriguez et al. “Quantum phenomena in attosecond science\,” Nat. Rev. Phys. 19 (2023) [2] D. N Purschke et al. “Microscopic mechanisms of highorderwavemixing in solids\,” Phys. Rev. A 108 (2023)[3] S. Lemieux et al. “Photon bunching in high‐harmonic emission controlled by quantum light” arXiv:2404.05474 \n\n\n\nVenue: RUN 0.35
URL:https://grk2905.de/event/grk-seminar-dr-david-n-purschke/
CATEGORIES:Seminar
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Berlin:20250217T093000
DTEND;TZID=Europe/Berlin:20250217T103000
DTSTAMP:20260429T210637
CREATED:20250215T114206Z
LAST-MODIFIED:20260326T162756Z
UID:1437-1739784600-1739788200@grk2905.de
SUMMARY:RTG Seminar: Cavity optomechanics in the few photon regime using nanowires and photonic crystals
DESCRIPTION:9:30 h \n\n\n\nDr. Chao Zhang: \n\n\n\n \n\n\n\nInstitut Néel; Université Grenoble-Alpes \n\n\n\n \n\n\n\nHuge developments have been done in the field of cavity optomechanics\, essentially by using large photon number to enhance the weak optomechanical interaction. Thus\, in our work\, we aim at approaching the single photon regime\, where a single photon in the cavity mode can have an appreciable impact on the nanowire\, which requires g_0>Ωm. This requires operating with ultrasensitive force sensors with small mode volume microcavities\, which enhance the electromagnetic field per photon. To do so\, we employ photonic crystal (PhC) cavities fabricated at C2N and suspended SiC nanowires\, whose vibrating extremity is inserted into the evanescent cavity field. The nanowire being smaller than the wavelength\, this allows us to image this confined light field\, and to map the optomechanical coupling strength. Then\, equiped with a probe laser and an external driving electrode\, we measure and map the optomechanical force experienced by the nanowire. Our results are compared to numerical simulations\, which also allows to understand the proximity forces arising when approaching the nanostructures.
URL:https://grk2905.de/event/grk-colloquium-prof-dr-rainer-hillenbrand-dr-alex-weber-bargioni/
CATEGORIES:Seminar
ATTACH;FMTTYPE=image/png:https://grk2905.de/wp-content/uploads/2024/10/Screenshot-2025-02-15-124055.png
END:VEVENT
BEGIN:VEVENT
DTSTART;TZID=Europe/Berlin:20250123T150000
DTEND;TZID=Europe/Berlin:20250123T160000
DTSTAMP:20260429T210637
CREATED:20241205T085651Z
LAST-MODIFIED:20260326T162816Z
UID:1541-1737644400-1737648000@grk2905.de
SUMMARY:RTG Seminar: doc. RNDr. Tomás Novotný:
DESCRIPTION:Optically induced excitonic shifts in transition metal dichalcogenide monolayers \n\n\n\n\n\nCharles University Prague \n\n\n\nIncreasing the speed limits of conventional electronics requires innovative approaches to manipulate other quantum properties of electrons besides their charge or spin. An alternative approach is the manipulation of the valley degree of freedom in semiconductors. In our study\, we demonstrate the possibility of the manipulation of such degrees of freedom in transition metal dichalcogenide monolayers using optical pulses on timescales of a few tens of femtoseconds. \n\n\n\n\n\n\n\n\n\n\n\n\n\nWe report on the theoretical and experimental investigation of valley-selective optical Stark and Bloch-Siegert shifts of exciton resonances in WSe2 and MoS2 monolayers induced by strong circularly polarized nonresonant optical fields. We predict and observe transient shifts of both 1sA and 1sB exciton transitions in the linear interaction regime. The theoretical description is based on semiconductor Bloch equations. The solutions of the equations are obtained with a modified perturbation technique\, which takes into account many-body Coulomb interaction effects. These solutions allow us to explain the polarization dependence of the shifts and calculate their values analytically. We found experimentally the limits of the applicability of the theoretical description by observing the transient exciton spectra change at high field amplitudes of the driving wave.References:[1] A. O. Slobodeniuk\, P. Koutenský\, M. Bartoš\, F. Trojánek\, P. Malý\, T. Novotný\, and M. Kozák\, npj 2D Mater Appl 7\, 17 (2023).[2] A. O. Slobodeniuk\, P. Koutenský\, M. Bartoš\, F. Trojánek\, P. Malý\, T. Novotný\, and M. Kozák\, Phys. Rev. B 106\, 235304 (2022). \n\n\n\nVenue: RUN auditorium \n\n\n\nGRK 2905 & SFB 1277 \n\n\n\nHost: Ferdiand Evers
URL:https://grk2905.de/event/doc-rndr-tomas-novotnyoptically-induced-excitonic-shifts-in-transition-metal-dichalcogenide-monolayers/
CATEGORIES:Seminar
ATTACH;FMTTYPE=image/png:https://grk2905.de/wp-content/uploads/2024/12/Screenshot-2025-01-15-115500-e1736938637998.png
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