Berlin 2024 – scientific programme

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O: Fachverband Oberflächenphysik

O 71: Poster: Plasmonics and Nanooptics

O 71.9: Poster

Wednesday, March 20, 2024, 18:00–20:00, Poster D

Ionization-assisted coherent optical two-dimensional nanoscopy — •Philipp Kessler, Luisa Brenneis, Victor Lisinetskii, Matthias Hensen, and Tobias Brixner — Institut für Physikalische und Theoretische Chemie, Universität Würzburg, Am Hubland, 97074 Würzburg

Optical two-dimensional (2D) spectroscopy has proven to be a powerful tool for the investigation of electronic couplings and ultrafast energy transport phenomena. The combination of this technique with photoemission electron microscopy (PEEM), i.e., coherent “2D nanoscopy”, enables the investigation of surface system dynamics with high spatio-temporal resolution [1]. However, photoemission may require multiple interactions with individual excitation pulses, causing overlapping signal contributions. The use of an additional ionization pulse circumvents this problem by projecting the population of the system’s states into the detection channel via photoemission, as shown in the gas phase [2]. Here, we present modifications of our existing PEEM setup [3] to realize this scheme. This includes second-harmonic generation on a separated beam path to produce the ionization pulse and optimization of the pulse-shaper generated four-pulse excitation sequence, which is accurately reconstructed by spectral interferometry. We further show a new beam stabilization system which enables stable incoupling into the freestanding PEEM by independently stabilizing both beam paths.

[1] M. Aeschlimann et al., Science 333, 1723 (2011).

[2] Uhl et al., Optica 8, 1316 (2021).

[3] Huber et al., Rev. Sci. Instrum. 90, 113103 (2019).

Keywords: ultrafast spectroscopy; 2D spectroscopy; photoemission electron microscopy