Speaker
Professor Alexandra Landsman
The Ohio State University
Abstract:
Recent advances in X‑ray free‑electron laser (XFEL) technology have opened new opportunities to probe photoionization dynamics on attosecond timescales and to access strong‑field regimes at X‑ray wavelengths that were previously experimentally inaccessible. In this talk, I will discuss two complementary classes of XFEL experiments that together illuminate the timing and mechanisms of electron emission in atoms and molecules. ÌýFirst, I will addressÌýattosecond photoemission delaysÌýmeasured using circular streaking techniques, with a focus on extending ionization‑delay chronoscopy fromÌýlinearly to circularly polarized probes.ÌýÌýI will also address the challenges of interpreting streaking delays at low photoelectron energies. ÌýSecond, I will present recent theoretical work exploring aÌýnew non‑perturbative strong‑field X‑ray regime, where multiphoton above‑threshold ionization (ATI) is driven by attosecond XFEL pulses. In helium, this regime produces distinct angular and spectral signatures that are clearly separated from perturbative harmonic contributions. ÌýTogether, these studies demonstrate how XFELs enable bothÌýquantitative attosecond chronoscopyÌýandÌýfundamental tests of strong‑field ionization physicsÌýat short wavelengths, establishing a foundation for future experiments in atoms and molecules.
ÌýAlexandra Landsman
Professor of Physics
The Ohio State University
Department of Physics
Physics 91ÌÒÉ« Building
191 W Woodruff Ave, Columbus, OH 43210
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