Strong-Field Dynamics Group

Dr. Boris Bergues


Research interests

Imaging of ultrafast processes in atoms and molecules

  • Electron Imaging Spectroscopy (VMI)
  • Electron Ion Coincidence Momentum Spectroscopy (COLTRIMS)

Nonlinear interactions of matter with attosecond XUV pulses

  • Generation of intense attosecond XUV pulses
  • Ion microscopy

Theory of strong field processes 

  • Semiclassical calculations
  • Quantum trajectory approaches

Strong field processes in solids

  • Light driven currents in solid materials
  • Time domain THz spectroscopy

Team members

Msc. Johannes Blöchl
Msc. Ritika Dagar
Msc. Weiwei Li
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.

Current Projects

3D Coincidence momentum spectroscopy

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.

Image: C. Hackenberger

Single-Cycle Non-Sequential Double Ionization
B. Bergues et al.
Journal of Selected Topics in Quantum Electronics 21, 8701009 (2015) | DOI: 

Attosecond tracing of correlated electron-emission in non-sequential double ionization

B. Bergues et al.
Nature Communications 3, 813 (2012) | DOI: 

Ion Microscopy

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.
Image: C. Hackenberger

Tabletop nonlinear optics in the 100-eV spectral region
B. Bergues et al.
Optica 5, 237 (2018) | DOI: 10.1364/OPTICA.5.000237

Spatially resolved measurement of ionization yields in the focus of an intense laser pulse
M. Schultze et al.
New Journal of Physics 13, 033001 (2011) | DOI: 10.1088/1367-2630/13/3/033001

 Reaction nanoscopy

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.
Image: RMT.Bergues

All-optical nanoscopic spatial control of molecular reaction yields on nanoparticles
W. Zhang et al.

Optica 9, 551 (2022) | DOI: 10.1364/OPTICA.453915
Near-Field Induced Reaction Yields from Nanoparticle Clusters
P. Rosenberger et al.
ACS Photonics 7, 1885 (2020) | DOI: 10.1021/acsphotonics.0c00823
Few-cycle laser driven reaction nanoscopy on aerosolized silica nanoparticles
P. Rupp et al.
Nature Communications 10, 4655 (2019) | DOI: 10.1038/s41467-019-12580-0

Ultrafast currents

In the ultrafast current project, we explore alternative routes to sample the field of few-cycle laser pulses. The principle relies on the generation of strongly driven currents in solids and gases. Beyond the application to CEP measurements and field sampling, we use the information contained in the ultrafast currents to gain a deeper understanding of the strong-field electron dynamics in various materials.
Image: RMT.Bergues

The emergence of macroscopic currents in photoconductive sampling of optical fields
J. Schötz et al.
Nature Communications 13, 962 (2022) | DOI:10.1038/s41467-022-28412-7
Femtosecond streaking in ambient air
A. Korobenko et al.
Optica 7, 1372 (2020) | DOI: 10.1364/OPTICA.398846
Single-shot carrier–envelope-phase measurement in ambient air

M. Kubullek et al.
Optica 7, 35 (2020) | DOI: 10.1364/OPTICA.7.000035

Thesis Supervision / Co-Supervision

PhD students:

2021 – present
Johannes Blöchl
Ultrafast sampling of laser induced currents
2020 − 2022
Ancyline Maliakkal
Ultrafast current studies in gases and solids
2019 – present
Ritika Dagar
Coincidence spectroscopy of ultrafast dynamics on nanostructures
2018 − 2023
Philipp Rosenberger
Ultrafast imaging of molecular reactions using electron-ion coincidence spectroscopy
2017 − 2023
Sambit Mitra
Reaction Nanoscopy of molecular reactions on the surface of nano-spheres
2016 − 2019
Philipp Rupp
Ultrafast dynamics on nanostructures in strong fields
2016 − 2018
Christian Burger
Laser Induced isomerization of hydrocarbons
2012 − 2016
Daniel Rivas
Generation of Intense Isolated Attosecond Pulses at 100 eV
2010 − 2014
Matthias Kübel
Single-Cycle Non-Sequential Double Ionization
2008 − 2011
Oliver Herrwerth
Atomic and Molecular Ionization Dynamics in Strong IR and XUV Fields Probed by Time-Resolved Coincidence Spectroscopy
2008 − 2012
Irina Znakovskaya
Light-Waveform Control of Molecular Processes
MSc students:
2021 – 2022
Lina Hedewig
Implementation of an Ion Microscope with Differential Evolution Based Autofocus
2020 – 2021
Johannes Blöchl
Laser field sampling with attosecond and nanometer precision
2017 − 2018
Thomas Weatherby
Reaction Nanoscopy: Near-Field-Induced, Dissociative Ionisation from Nanoparticles in Solution
2017 − 2018
Philipp Rosenberger
Control of quantum dynamics in H2 by ultra-short phase-stable laser pulses
2016 − 2017
Wilhelm Frisch
Light-Waveform Control of Molecular Processes
2014 − 2015
Alexander Muschet
Ion Microscopy for Attosecond XUV Pulse Diagnostics
Till Hause
Characterization of a GRENOUILLE
BSc students:
Jonas Zimmermann
Optical Characterization of Aerosolized Nanoparticles
2019 − 2020
Franz Haniel
Development of a New Ion Microscope Design Using Machine Learning Tools
2018 − 2019
Klaas von der Brelje
Ultrafast Dynamics in Nano-layer Materials
2017 − 2018
Max Kubullek
CEP Measurement of Circularly Polarized Laser Pulses in Fused Silica