Imaging of ultrafast processes in atoms and molecules
Nonlinear interactions of matter with attosecond XUV pulses
Theory of strong field processes
Strong field processes in solids
Msc. Ritika Dagar
Msc. Weiwei Li
Msc. Ancyline Maliakkal
Msc. Sambit Mitra
Msc. Philipp Rosenberger
Dr. Hartmut Schröder
Dr. Zilong Wang
What happens when matter is exposed to intense laser pulses with electric fields comparable to those holding the electrons bound to the nuclei? How can we use such strong electric fields to control and steer the electron motion with a precision reaching down into the attosecond time scale? These are questions addressed in the strong field physics team. We are working with different experimental setups to investigate these questions in various materials, ranging from atoms and molecules to solids. The work horse of our experimental research are ultrashort laser pulses generated with state-of-the-art laser systems, and with durations barely longer than a single light wave oscillation.
In the COLTRIMS (COLd Target Recoil Ion Momentum Spectroscopy) project, the interaction of near single cycle laser pulses with atoms and molecules is studied by measuring the momentum of the fragments (electrons and ions) in coincidence. The combination of COLTRIMS with single-shot carrier-envelope phase measurements enables the control of ionization and dissociation processes with sub-cycle temporal resolution.
Attosecond tracing of correlated electron-emission in non-sequential double ionization
B. Bergues, M. Kübel, N. Kling, B. Fischer, N. Camus, K. Betsch, O. Herrwerth, A. Senftleben, A. M. Sayler, T. Rathje, T. Pfeifer, I. Ben-Itzhak, R. R. Jones, G. Paulus, F. Krausz, R. Moshammer, J. Ullrich, M. Kling
Nature Communications 3, 813 (2012) | DOI: 10.1038/ncomms1807
When ultrashort and intense laser pulses are focused onto an atomic gas, different ionic charge states are generated upon multiple photoionization. The spatial distribution of the different charge states depends on the intensity distribution in the laser focus. By spatially resolving the charge state distribution, our ion microscopy technique provides access tointensity resolved ion yields. The technique is particularly well suited to studying ultrafast light-matter interactions in the XUV spectral range. It has recently allowed the first demonstration ofnonlinear interactions between attosecond XUV pulses and core electrons in xenon.
Tabletop nonlinear optics in the 100-eV spectral region
B. Bergues, D. Rivas, M. Weidman, A. Muschet, W. Helml, A. Guggenmos, V. Pervak, U. Kleineberg, G. Marcus, R. Kienberger, D. Charalambidis, P. Tzallas, H. Schröder, F. Krausz, L. Veisz
Optica 5, 237 (2018) | DOI: 10.1364/OPTICA.5.000237
Reaction nanoscopy is a novel technique designed to study the interaction of few-cycle laser pulses with nanoparticles and molecules adsorbed on their surface. Nanoparticles are of great interest in nanochemistry since they offer unique properties as photo-catalysts due to their large surface area. Enhanced near-fields, induced on the nanoparticle’s surface under irradiation with ultrashort light pulses can be used to control molecular photoionization and dissociation reactions on the nanoscale.
Few-cycle laser driven reaction nanoscopy on aerosolized silica nanoparticles
P. Rupp, C. Burger, N. Kling, M. Kübel, S. Mitra, P. Rosenberger, T. Weatherby, N. Saito, J. Itatani, T. Otsuka, A. Alnaser, M. Raschke, E. Rühl, A. Schlander, M. Gallei, L. Seiffert, T. Fennel, B. Bergues, M. Kling
Nature Communications 10, 4655 (2019) | DOI: 10.1038/s41467-019-12580-0
In the ultrafast current project, we explore alternative routes for the measurement of the carrier-envelope phase (CEP) of few-cycle laser pulses that rely on strongly driven currents in solid-state samples. Beyond the application to CEP measurements, we take advantage of the information contained in the CEP-dependent current to gain a deeper understanding of the electron dynamics in various solid materials exposed to strong few cycle laser pulses.