Conveners
Poster session 1: (snacks and refreshments served)
- Manfred Lein (Leibniz Universität Hannover)
- Jochen Küpper (Center for Free Electron Laser Science, DESY and Universität Hamburg)
Sajal Kumar Giri
(Max Planck Institute for the Physics of Complex Systems, Dresden)
14/02/2018, 17:00
Poster
Poster
Strong field quantum dynamics are very sensitive to the shape of the interacting field. Finding a suitable pulse shape to reach a predefined target lies in the heart of quantum control. The forward non-linear mapping between the interacting pulse and the objective (photo-electron spectra(PES)) can be achieved by solving the time-dependent Schrödinger equation. However, the non-linear inverse...
Sergej Neb
(University of Bielefeld)
14/02/2018, 17:00
Poster
Poster
Attosecond time-resolved photoemission based on the photoelectron streaking in a time-correlated strong IR field allows investigating temporal delays in the photoemission from different initial states with unprecedented resolution [1]. The physical origin of these delays is not yet fully understood and various theoretical models coexist demonstrating our still limited understanding of the...
Birger Böning
(Friedrich-Schiller-Universität Jena)
14/02/2018, 17:00
Poster
Poster
Attosecond streaking is an established technique to measure timing
information in the interaction of ultrashort laser pulses with atoms
or molecules. This technique is based on the photoionization by an
attosecond laser pulse in the presence of a strong linearly polarized
near infrared (NIR) laser pulse. We investigate the attosecond streaking
with an X wave pulse carrying orbital angular...
Anne Harth
(Max-Planck-Institut für Kernphysik, Heidelberg)
14/02/2018, 17:00
Poster
Poster
To directly observe the ultrafast motion of electrons in atomic or molecular systems is an aspect of fundamental physics and is achievable thanks to the generation of attosecond pulses in the XUV spectral range. A key advantage of attosecond pulse trains over isolated attosecond pulses is their high spectral resolution, while high temporal resolution is still retained [1]. I will introduce...
Victor Despré
(Universität Heidelberg)
14/02/2018, 17:00
Poster
Poster
A particular charge migration dynamics, driven only by the electron correlation, occurs in the propiolic acid molecule after the ionization of its HOMO orbital. This dynamics consist of an oscillation of the charge between its carbon triple bond and its carbonyl oxygen with a period of 6.2 fs. Performing fully quantum coupled electron-nuclear dynamics calculation, taking into account all 26...
Timo Paschen
(Friedrich-Alexander-Universität Erlangen-Nürnberg)
14/02/2018, 17:00
Poster
Poster
We demonstrated two-color coherent control of multi-photon photoemission from a tungsten nanotip with the optical phase between two light fields [1] and now continue to investigate the coherent nature of two-color above-threshold photoemission from nanotip sources. As discussed in [1], by focusing 74 fs drive pulses at 1560 nm and their second harmonic at 780 nm onto the tip and changing the...
Stefanie Kerbstadt
(Carl von Ossietzky Universität Oldenburg, Institut für Physik)
14/02/2018, 17:00
Poster
Poster
Polarization-tailored bichromatic laser fields with commensurable center frequencies have emerged as a new twist to steer ultrafast electron dynamics. Recently, we introduced a novel approach to the generation of polarization-tailored bichromatic fields, based on ultrafast pulse shaping of an octave-spanning Carrier Envelope Phase (CEP)-stable white light supercontinuum [1-2]. The shaper-based...
Nikolay SHVETSOV-SHILOVSKIY
(Institute for Theoretical Physics, Leibniz University Hannover)
14/02/2018, 17:00
Poster
Poster
Strong-field photoelectron holography (SFPH) is a new method for time-resolved molecular imaging [1]. The SFPH technique is based on the interference between rescattered electrons that are driven back to their parent ions and rescatter on them, and direct electrons that do not recollide with the ions. The semiclassical three-step model [2] accounting only for the laser field predicts four...
Marec Heger
(Universität Kassel)
14/02/2018, 17:00
Poster
Poster
Coherent control of bond making in chemical reactions has recently been successfully demonstrated under thermal conditions. In this experiment, pairs of magnesium atoms were made to collide at a temperature of around 1000 K and were subsequently excited into electronically excited states by a femtosecond laser pulse. The resulting UV emission signal proved to be a clear indicator of the...
Terry Mullins
(CFEL)
14/02/2018, 17:00
Poster
Poster
Fixing molecules in space enables a variety of investigations into molecular structure and dynamics, such as high harmonic spectroscopy or ultrafast diffractive imaging of molecular dynamics. Molecules can be aligned and oriented to the laboratory frame using suitable ac and dc electric fields [1,2]. State-selection can lead to a significant enhancement of the degrees of alignment and...
Katharina Priebe
(4th Physical Institute – Solids and Nanostructures, University of Göttingen)
14/02/2018, 17:00
Poster
Poster
Programmable phase-shaping of free-electron wavefunctions is expected
to significantly enhance the capabilities of electron microscopy. In
particular, temporal shaping by optical fields promises time-resolved
electron diffraction and imaging with attosecond precision.
Here, we demonstrate the generation, coherent control and
characterization of free-electron momentum superposition...
Matthias Paul
(Institut für Physikalische Chemie, Universität Jena)
14/02/2018, 17:00
Poster
Poster
We examine the circular dichroism in the photoelectron momentum distribution of triatomic model systems ionized by strong-field ionization. We demonstrate how the symmetry and electronic structure of the system is imprinted into the photoelectron momentum distribution. We use classical trajectories to reveal the origin of the three-folded pattern in the photoelectron momentum distribution, and...
Jonas Wätzel
(Martin-Luther Universität Halle-Wittenberg)
14/02/2018, 17:00
Poster
Poster
Recent advances in generating structured light fields for a wide range of pulse parameters has led to important discoveries and fascinating applications ranging from optical tweezers for microscale objects to electronics, life sciences, quantum information or optical telecommunications. Especially light pulses carrying orbital angular momentum (OAM) enable photomechanics for moving, trapping...
Lutz Marder
(Institut für Physik, Universität Kassel)
14/02/2018, 17:00
Poster
Poster
An explicit time-dependence of the Hamiltonian, for example due to an external driving field, introduces an additional challenge for dynamical simulations. The most commonly used propagation approaches usually rely on dividing the overall propagation time into small steps, in which the time-dependence of the Hamiltonian is approximately constant and the time evolution operator becomes a matrix...
Johannes Schötz
(Max-Planck-Institute for Quantum Optics, Garching)
14/02/2018, 17:00
Poster
Poster
The interaction of light with nanostructures shows unique properties such as enhancement and confinement of the electric near field down to a few nanometer. In strong-field photoemission from nanotips, as a consequence of the latter, electrons can experience the decay of the electric field amplitude and therefore the ponderomotive potential already during the time scale of a laser cycle. We...
Jan Reislöhner
(Institute of Optics and Quantum Electronics, FSU Jena)
14/02/2018, 17:00
Poster
Poster
Pulses with durations short enough to probe the electronic timescale can be generated in the XUV and in the IR-VIS regime. At photon energies around 4-20 eV, pulses with such extremely short durations have not yet been demonstrated. Frequency conversion in a gas cell or filamentation yields comparatively short pulses, but the complex interplay of nonlinear light-matter interaction and...
Evangelos Karamatskos
(CFEL, Universität Hamburg)
14/02/2018, 17:00
Poster
Poster
Field-free alignment and orientation of molecules is an important prerequisite for many gas phase
imaging experiments. It allows to access information directly in the molecular frame and extract
observables such as internuclear distances, angles and the electronic density through a
measurement of the photoelectron angular distribution.
We present new experimental results and simulations on...
Dominik Schomas
(Albert-Ludwigs Universität, Freiburg)
14/02/2018, 17:00
Poster
Poster
A doped helium nanodroplet irradiated by intense near-infrared (NIR) laser pulses forms a highly ionized nanoplasma even at laser intensities where the helium is not directly ionized. The dopant atoms provide first seed electrons which start the electron impact ionization avalanche of the whole droplet. The dynamics of ignition and explosion of the nanoplasma depends not only on the number and...
Andrey Yachmenev
(CFEL, DESY, CUI Hamburg)
14/02/2018, 17:00
Poster
Poster
Chirality is now one of the top-class subjects in physical, chemical and biological academic research as well as industrial pharmacology. Accurate experimental characterisation of the enantiomeric excess and absolute handiness in mixtures of chiral molecules, efficient chiral purification and discrimination remain very challenging and highly demanding tasks for a broad scope of applications. A...
Christoph Jusko
(Institut für Quantenoptik, Leibniz Universität Hannover)
14/02/2018, 17:00
Poster
Poster
Filaments are an interesting phenomenon caused by high-intense laser pulses in various media. If a femtosecond laser pulse exceeds a certain critical peak power, the laser beam will experience ongoing self-focusing due to the Kerr effect, causing an intensity-dependent nonlinear refractive index n2, as the self-focusing enhances itself. Eventually, the self-focusing beam exceeds the ionization...
Florian Oppermann
(Uni Hannover)
14/02/2018, 17:00
Poster
Poster
The helium hydride molecular ion, HeH+, is the simplest heteronuclear
polar molecule and serves as a benchmark system for the investigation of
multi-electron molecules and molecules with a permanent dipole. We
specifically address the question: How does the permanent dipole of HeH+
affect the fragmentation dynamics in intense ultrashort laser pulses? We
study the laser induced...
Nicolai Klemke
(CFEL, DESY Hamburg)
14/02/2018, 17:00
Poster
Poster
We analyse the polarization states of high-harmonics generated
with strong elliptical laser pulses in silicon. We find that the
polarization states are dependent both on crystal symmetries and
nonperturbative dynamics. Circular harmonics can be generated with
circular and non-circular drivers which could pave the way to relatively
simple sources of circular XUV pulses.
Lun Yue
(Friedrich Schiller Universität Jena)
14/02/2018, 17:00
Poster
Poster
Strong-field-induced rotation and ionization of HeH+ are investigated. The nuclei are treated as classical trajectories moving on field-dressed potential energy surfaces, while single and double ionization are simulated as stochastical jumps to the ionic surfaces, using the internuclear-distance- and orientation-dependent static ionization rates obtained from many-electron...
Sebastian Eckart
(Goethe-Universität Frankfurt am Main)
14/02/2018, 17:00
Poster
Poster
We report on our results on studying single ionization of helium in counterrotating circular two-color (CRTC) laser fields (780 nm & 390 nm) with overall intensities of up to 8*10^14 W/cm^2. The three dimensional momenta of the fragments are recorded using Cold Target Recoil Ion Momentum Spectroscopy (COLTRIMS) as experimental technique. We present our new results regarding single...
Christian Markus Dietrich
(Institute of Quantum Optics, Leibniz Universität Hannover)
14/02/2018, 17:00
Poster
Poster
Ultrafast light sources with a wavelength around two micrometers are
interesting for several experiments like high harmonic generation and
investigation of Brunel harmonics. We want to present a doubly
resonant optical parametric oscillator (DROPO) for intracavity experiments.
Our system is pumped by a home built kerr lens mode locked
Yb:YAG thin disk laser with a repetition rate of 34...
Nicolas Eicke
(Universität Hannover)
14/02/2018, 17:00
Poster
Poster
The attoclock technique [1] in which the emission time of a photoelectron is mapped to its detection
angle is an important tool in strong-field ionization of atoms. However, the use of close-to-circularly polarized
laser fields is inherent to the method and all conclusions drawn from the attoclock are stricly valid
only in this kind of orthogonal tunneling geometry, which is characterized...
Bing Zhang
(Harbin Institute of Technology, China; Leibniz Universität Hannover)
14/02/2018, 17:00
Poster
Poster
We study the ionization times of electrons in high-order harmonic generation from oriented HeH+ through numerical solution of the time-dependent Schrödinger equation. With using orthogonally polarized two-color laser pulses composed of an intense fundamental field and a time-delayed weak second-harmonic field, we probe the sub-cycle electron dynamics as the polarization of the fundamental...
Tristan Müller
(MPI of Microstructure Physics, Halle)
14/02/2018, 17:00
Poster
Poster
We propose a generalization of the Bloch state which involves an additional sum over a finer grid in reciprocal space around each k-point. This allows for ab-initio calculations of ultra long-range modulations in the density which may involve millions of unit cells but with an efficiency rivaling that of single unit cell. This is due to a new algorithm developed specifically for solving the...
