SKM 2023 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 48: Ultra-fast Phenomena
HL 48.5: Talk
Friday, March 31, 2023, 10:30–10:45, POT 251
Imaging nanoscale electron dynamics with extreme ultraviolet radiation — •Hung-Tzu Chang1, Sergey Zayko1, Jakob Hagen1, Murat Sivis1,2, and Claus Ropers1,2 — 1Max Planck Institute for Multidisciplinary Sciences, 37077 Goettingen, Germany — 24th Physical Institute, University of Goettingen, 37077 Goettingen, Germany
Non-equilibrium electronic processes such as electron thermalization, ballistic transport, and spin diffusion, occur at femtosecond time- and nanometer length-scales. While ultrafast spectroscopic methods can trace the temporal evolution of electronic states [1], capturing those dynamics in real space remains challenging. Here we demonstrate time-resolved coherent diffractive imaging using a table-top extreme ultraviolet (EUV) source based on high harmonic generation [2,3], where the sample is first excited by a near-infrared pump pulse and probed with core-level absorption induced by a time-delayed EUV pulse. The valence electron dynamics can be retrieved from the spatially resolved changes of the EUV field amplitude and phase exiting the sample after localized photoexcitation. This technique provides nanometer spatial resolution in addition to the time resolution and element specificity of femtosecond table-top core-level spectroscopy, and paves the way for further understanding of the mechanisms of photophysical processes in condensed matter.
[1] Chang et al., Phys. Rev. B 103(6), 064305 (2021). [2] Kfir et al., Sci. Adv. 3(12), eaao4641 (2017). [3] Zayko et al., Nat. Commun. 12(1), 6337 (2021)