Freiburg 2024 – wissenschaftliches Programm

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A: Fachverband Atomphysik

A 26: Poster V

A 26.12: Poster

Mittwoch, 13. März 2024, 17:00–19:00, Tent C

Signatures of IR-laser dressing in coherent diffractive imaging — •Tom von Scheven, Björn Kruse, Bjarne Mergl, Christian Peltz, and Thomas Fennel — Institute of Physics, University of Rostock, Albert-Einstein-Str. 23-24, D-18059 Rostock, Germany

Single-shot coherent diffractive imaging (CDI) enables the capture of a full diffraction image of a nanostructure using a single flash of XUV or X-ray light. The resulting scattering image encodes both the geometry and the optical properties of the target. So far, this method has mainly been employed for ultrafast structural characterization [1]. However, CDI can also be utilized to resolve ultrafast optical property changes caused by e.g. transient excitation from nonlinear scattering [2], or by illumination with a second ultra-short laser pulse.

Here, we explore the expected signatures for the latter case theoretically, where simultaneous exposure to a strong IR field can induce transient optical properties. To this end, the effective optical properties emerging from the laser dressing must be determined and used to describe the resulting scattering process, which we model using the well-known Mie-solution. We extract the effective optical properties from the dipole response of a local quantum description based on an atom-like solution of the time-dependent Schrödinger equation. The identification of the states and processes responsible for these properties and the corresponding features in the diffraction image is performed by a systematic comparison with results for a few-level system.

[1] I. Barke et al., Nat. Commun. 6, 6187 (2015)

[2] B. Kruse et al., J. Phys.: Photonics 2, 024007 (2020)

Keywords: transient optical properties; laser dressing; time-dependent Schrödinger equation; coherent diffractive imaging; Mie-scattering