Research Overview

Andreas Becker photo.

Our research interests are related to the theory of ultrafast processes in atoms, molecules and nanostructures induced, observed and controlled by ultrashort intense laser pulses. Electric field strengths of such laser pulses can exceed those of the Coulomb fields within an atom or molecule while the pulse durations are as short as a few femtoseconds (10-15 s) or even shorter in the attosecond regime (1 as = 10-18 s). Laser frequencies range from the far-infrared through the optical to the soft x-ray region.

Research Areas

  • The quest for studying ultrafast dynamics in matter has driven the development of laser pulses with ultrashort pulse durations. Currently, the shortest pulses have duration of a few tens of attoseconds (1 as = 10-18 s). We study the application of such pulses to image electron dynamics in atoms and molecules.

  • It is nowadays possible to generate laser pulses at wavelengths spanning the whole regime from deep-ultraviolet to midinfrared wavelengths. Moreover, control over pulse duration, carrier envelope phase and polarization has been achieved. We explore the application of this laser light for fundamental processes such as ionization, high harmonic generation etc.

  • While many effects in strong-field physics can be described using the single-active-electron approximation, energy transfer between electrons is mediated with electron correlation. We attempt to capture multielectron effects driven by short intense laser pulses.

  • The absorption of a single photon by matter is well understood. But, how does our understanding of the underlying quantum effects, such as selection rules, extend if an atom or molecule absorbs more than one photon from an intense laser field?

  • To study the highly nonlinear and nonperturbative interaction of intense laser light with matter we develop and apply several theoretical approaches, ranging from ab-initio numerical solutions to various approximation methods.