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arXiv · 2106.07926

Using the photo-induced $L_3$ resonance shift in Fe and Ni as time reference for ultrafast experiments at low flux soft X-ray sources

Somnath Jana·Shreyas Muralidhar·Johan Åkerman·Christian Schüßler-Langeheine·Niko Pontius
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Abstract

We study the optical-pump induced ultrafast transient change of the X-ray absorption at the $L_3$ absorption resonances of the transition metals Ni and Fe in Fe$_{0.5}$Ni$_{0.5}$ alloy. We find the effect for both elements to occur simultaneously on a femtosecond timescale. This effect may hence be used as a handy cross-correlation scheme providing a time-zero reference for ultrafast optical-pump soft X-ray-probe measurement. The method benefits from a relatively simple experimental setup as the sample itself acts as time-reference tool. In particular, this technique works with low flux ultrafast soft X-ray sources. The measurements are compared to the cross-correlation method introduced in an earlier publication.

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Somnath Jana, Shreyas Muralidhar, Johan Åkerman, Christian Schüßler-Langeheine, Niko Pontius. 2021-06-15. Using the photo-induced $L_3$ resonance shift in Fe and Ni as time reference for ultrafast experiments at low flux soft X-ray sources. https://arxiv.org/abs/2106.07926

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