Strong Field Physics Group

Due to recent advances in laser technology, ultra high intense laser pulses of short durations are
routinely produced in contemporary laboratories. The technological progress led to the development of
petawatt lasers that deliver laser radiation in the visible spectrum with intensities as high as 1022 W/cm2.
On the other hand, the synthesis of laser pulses which contain only a few optical cycles and last in the
femtosecond or attosecond time-domain is currently feasible. Our theory group pursues the research in
both these areas, i.e., in the area of high field physics and attoscience.

The main focus of our current research in high field physics is in the domain of strong-field
quantum electrodynamics (QED). Historically, strong-field QED is the oldest strong-field-physics area,
as investigations of fundamental QED processes in laser fields began already in the 1960s. While the
problem was of purely theoretical interest at that time, currently there is a clear perspective for
corresponding experimental studies due to a remarkable and still ongoing progress in high-power laser
technology. Our studies in this area concern such fundamental QED processes as Compton scattering,
and electron-positron pair creation via the Breit-Wheeler and the Bethe-Heitler scenarios. Our main
objective is to theoretically study how to control these processes by means of laser radiation. In this
area we collaborate with the group of Prof. Christoph Keitel (Max Planck Institute, Germany) and Prof.
Carsten Müller (University of Düseldorf, Germany). Our future research may include work with the
Extreme Light Laboratory at the University of Nebraska, USA, headed by Prof. Donald Umstadter. In
the area of nonrelativistic strong laser physics, we have long-standing collaboration with Prof. Robert
Potvliege from the Durham University, UK, and Prof. Anthony Starace and Prof. Ilya Fabrikant from
the University of Nebraska, USA. Our work in this area focuses on studies of multiphoton processes
that are not only stimulated but might be also manipulated by the laser field (leading, for instance, to
enhancement of above-threshold ionization or high-order harmonic generation). Our interests extend to
low-dimensional systems whose properties, as our study shows, might be strongly modified by the
presence of external (both static and time-dependent) electromagnetic fields.

We are involved in the program entitled “International PhD studies at the Faculty of Physics
University of Warsaw”, that is sponsored by the Foundation for Polish Science within the European
Regional Development Fund. Felipe Cajiao-Veléz is a PhD student who joined our group to work in the
area of attoscience. His research concerns engineering and control of quantum processes by attosecond
laser pulses, and is primarily centered around two problems: quantum control of transport in
nanostructures along with quantum control of ionization and high harmonic generation by attosecond
pulses. The project is conducted in collaboration with the Ultrafast AMO Theory Group headed by
Prof. Andreas Becker and Dr Agnieszka Jaroń-Becker from the University of Colorado and JILA, USA.

Research projects:

  • “Laser-induced pair creation processes in quantum electrodynamics” - grant of the Polish National Science Center (2011-2014); K. Krajewska – principal investigator
  • “Quantum processes in ultrashort laser pulses” - grant of the Polish National Science Center (2013-2016); J. Kamiński – principal investigator