International research opportunities for students program report of Su Xingyu
Doctoral student Su Xingyu from I. Matsuda Group conducted research through ISSP International Research Opportunities for Student Program at the University of California, Berkeley in the United States from September 9 to October 10, 2025. This program, initiated in 2017, aims to foster international talent through collaborative research abroad, sending graduate students to overseas research institutions for several months.
Su Xingyu, I. Matsuda Group D1
Purpose
Advances in X-ray free-electron lasers (XFELs) and high-harmonic-generation (HHG) table-top lasers have enabled time-resolved soft X-ray spectroscopies for probing ultrafast electronic dynamics with element specificity. A central challenge in such experiments is determining the exact temporal overlap (“time zero”) between pump and probe pulses. This visit focused on learning mature table-top XUV techniques in time-resolved experiment to support the development of more precise pump–probe measurements at XFEL facilities.
Summary
I conducted a one-month research visit at the University of California, Berkeley, in Professor Michael Zuerch’s group, focusing on table-top high-harmonic generation extreme ultraviolet spectroscopy with attosecond time resolution. This experience deepened my understanding of ultrafast spectroscopy and provided valuable insights that will contribute to developing advanced pump–probe experiments using X-ray free-electron lasers (XFELs) in my future research.
Activity
During my one-month research visit at the University of California, Berkeley, I worked in Professor Michael Zuerch’s group to explore cutting-edge table-top high-harmonic generation (HHG) extreme ultraviolet (XUV) spectroscopy with attosecond time resolution [Fig. 1]. This experience allowed me to closely engage with state-of-the-art attosecond light sources and learn key experimental techniques, including the generation and characterization of XUV pulses, precise alignment of attosecond pump–probe systems, and analysis of time-resolved photoabsorption dynamics in solids. The intensive training not only strengthened my experimental skills but also provided valuable insights into ultrafast electron dynamics, directly enriching my ongoing research on light–matter interactions and element-resolved nonlinear optical phenomena using soft X-ray sources.
During my stay at the University of California, Berkeley, I also had the opportunity to visit Dr. Walter Drisdell in the Lawrence Berkeley National Laboratory (LBNL) [Fig. 2], where I learned about large-scale experimental facilities and ongoing research in materials characterization. In addition, I visited San Francisco and the Golden Gate Bridge [Fig. 3], which provided valuable cultural and personal experiences, helping me gain a broader perspective of life and research in the United States. These experiences enriched my stay and deepened my appreciation for the international research environment.
Related page
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