Tatiana Bezriadina, University of Hamburg/ The Hamburg Centre for Ultrafast Imaging

Abstract:

It is well known that ultrafast EUV/X-ray pulses provide us with a unique opportunity to explore electron dynamics on angstrom scale with up to the femtosecond resolution. In addition, resonance X-ray pulses represent atomic selective tool to observe dynamics in quantum systems. It appears as though the EUV/X-ray absorption of a laser-driven electronic system is a tool to reveal a complexity of the properties of nonlinear optical response in real time and on atomic scale.

Methods:

The Floquet formalism is applied to characterize the interaction between an electronic system and driving electromagnetic field beyond the perturbation theory. The density matrix formalism is applied to describe the absorption probability of a probe pulse with arbitrary duration. The interaction between a laser-driven electronic system and probe pulse is studied within the first order perturbation theory on the interaction Hamiltonian. The tools for numerical computations are considered including Exciting Code (a full-potential all-electron package implementing density-functional theory and many-body perturbation theory).

Results and Discussion:

We derive the absorption probability of an X-ray pulse with arbitrary duration, shape and following several assumptions get the absorption probability in the particular case of narrow X-ray pulse.

In this case the derived spectrum is represented by the sequence of absorption peaks of different optical response orders. Therein a pick width depends on the duration of the probe X-ray pulse and its intensity is defined via the forms of the initial and final reference Floquet states along with dipole transition moment between core and valence state.

Poster Session Link: https://gather.town/invite?token=0pEoq7VP

If you have any questions for the presenter, please contact them via email: tatiana.bezriadina@uni-hamburg.de