スーパーX線技術で原子レベルの詳細を可視化（Super-resolution X-ray technique reveals atomic insights with unprecedented detail）

2025-07-16 アルゴンヌ国立研究所 (ANL)

An incoming X-ray light wave (left) made up of a chaotic distribution of very fast spikes interacts with atoms (purple dots) in a gas to amplify specific spikes (right) in the light wave. (Image by Stacy Huang/Argonne National Laboratory.)

＜関連情報＞

• https://www.anl.gov/article/superresolution-xray-technique-reveals-atomic-insights-with-unprecedented-detail
• https://www.nature.com/articles/s41586-025-09214-5

超解像刺激X線ラマン分光法 Super-resolution stimulated X-ray Raman spectroscopy

Kai Li,Christian Ott,Marcus Agåker,Phay J. Ho,Gilles Doumy,Alexander Magunia,Marc Rebholz,Marc Simon,Tommaso Mazza,Alberto De Fanis,Thomas M. Baumann,Jacobo Montano,Nils Rennhack,Sergey Usenko,Yevheniy Ovcharenko,Kalyani Chordiya,Lan Cheng,Jan-Erik Rubensson,Michael Meyer,Thomas Pfeifer,Mette B. Gaarde & Linda Young
Nature  Published:16 July 2025
DOI:https://doi.org/10.1038/s41586-025-09214-5

Abstract

Propagation of intense X-ray pulses through dense media has led to the observation of phenomena such as atomic X-ray lasing^1,2, self-induced transparency³ and stimulated X-ray Raman scattering (SXRS)⁴. SXRS has been long predicted as a means to launch and probe valence-electron wavepackets and as a building block for nonlinear X-ray spectroscopies^5,6. However, experimental observations of SXRS to date^4,7,8 have not provided spectroscopic information, and theoretical modelling has largely implemented hard-to-realize phase-coherent attosecond pulses. Here we demonstrate SXRS with spectroscopic precision, that is, detection of valence-excited states in neon with a near Fourier-limited joint energy–time resolution of 0.1 eV–40 fs. We used a new covariance analysis between statistically spiky broadband incident X-ray and scattered X-ray Raman pulses. Using 18,000 single shots, we beat not only the incident (about 8 eV) bandwidth but also the  approximately 0.2 eV instrumental energy resolution, thus creating super-resolution conditions, in analogy to super-resolved fluorescence microscopy⁹. Our experimental results, supported by ab initio propagation simulations, reveal the competition between lasing in the ion and stimulated Raman scattering in the neutral. We demonstrate enhanced signal collection efficiency and a broad excitation window, surpassing spontaneous Raman efficiencies by orders of magnitude. This stochastic SXRS approach represents a first step towards tracking elementary events that determine chemical outcomes¹⁰.