题目：X-ray Superfluorerscence
报告人：Nina Rohringe 教授
报告人单位：Hamburg University
主持人：吴健 教授
时间：2025年5月9日（周五）10:00至11:30
地点：闵行校区光学大楼B325会议室
报告人简介：
Prof. Nina Rohringe got her PhD at the Vienna University of Technology in 2005. After graduation, she carried out postdoctoral research at the Argonne National Laboratory and the Lawrence Livermore National Laboratory. Afterwards, she acted as a group leader at the Max Planck Institute for the Physics of Complex System and the Max Planck Institute for the Structure and Dynamics of Matter. Since 2017, she is a full professor of physics at the Hamburg University and the lead scientist at DESY. Prof. Rohringe has received a number of prestigious honors, e.g., she was elected as the Fellow of the American Physical Society in 2023 and served as the editorial board member of Physical Review A.
报告内容简介：
X-ray free-electron lasers (XFELs) open new avenues towards studying collective x-ray emission and nonlinear x-ray matter interaction. In this talk I will give a retrospective on the phenomenon of collective spontaneous x-ray emission following ultrafast inner-shell photoinization (x-ray superfluorescence). Theory as well as experimental achievements will be discussed. X-ray superfluorescence has been demonstrated in atomic gases in the soft x-ray range [1], in rare-gases [2] and clusters [3] in the XUV, and in solids and liquids in the hard x-ray range [4,5]. As opposed to the XFEL pulses that are based on the process of self-amplified spontaneous emission (SASE) and have limited temporal coherence, x-ray superfluorescence produces phase-stable, ultrabright x-ray pulses of fs and sub-fs duration [6,7]. Using this principle of inner-shell x-ray lasing, I discuss two new proposals for further tailoring x-ray pulses: By combining collective x-ray emission and Bragg scattering in a crystal --- an x-ray analogue of a distributed feedback laser --- it is possible to create phase-stable pairs of x-ray pulses in the hard x-ray spectral region. Furthermore, we propose a set-up for an x-ray laser oscillator that combines a Bragg cavity, serving as monochromator, and a multi-pass superfluorescent emission [8], thereby offering the opportunity to create x-ray pulses of unprecedented brightness and narrow bandwidth.
[1] N. Rohringer et al., Nature 481, 488 (2012).
[2] L. Mercadier et al., Physical Review Letters 123, 023201 (2019).
[3] A Benediktovitch et al., Physical Review A 101, 063412 (2020).
[4] T. Kroll et al., Physical Review Letters 120, 133203 (2018).
[5] T. Kroll et al., Physical Review Letters 125, 037404 (2020).
[6] M. D. Doyle et al., Optica 10, 1602 (2023).
[7] C. Weninger and N. Rohringer, Physical Review A 90, 063828 (2014).
[8] A. Halavanau et at., Proceedings of the National Academy of Sciences 117, 15511 (2020).