%0 Journal Article
%A Linker, Thomas M.
%A Halavanau, Aliaksei
%A Kroll, Thomas
%A Benediktovitch, Andrei
%A Zhang, Yu
%A Michine, Yurina
%A Chuchurka, Stasis
%A Abhari, Zain
%A Ronchetti, Daniele
%A Fransson, Thomas
%A Weninger, Clemens
%A Fuller, Franklin D.
%A Aquila, Andy
%A Alonso-Mori, Roberto
%A Boutet, Sebastien
%A Guetg, Marc W.
%A Marinelli, Agostino
%A Lutman, Alberto A.
%A Yabashi, Makina
%A Inoue, Ichiro
%A Osaka, Taito
%A Yamada, Jumpei
%A Inubushi, Yuichi
%A Yamaguchi, Gota
%A Hara, Toru
%A Babu, Ganguli
%A Salpekar, Devashish
%A Sayed, Farheen N.
%A Ajayan, Pulickel M.
%A Kern, Jan
%A Yano, Junko
%A Yachandra, Vittal K.
%A Kling, Matthias F.
%A Pellegrini, Claudio
%A Yoneda, Hitoki
%A Rohringer, Nina
%A Bergmann, Uwe
%T Attosecond Inner-Shell Lasing at Angstrom Wavelengths
%J Nature
%V 642
%N arXiv:2409.06914
%@ 0028-0836
%C London [u.a.]
%I Nature Publ. Group
%M PUBDB-2025-01093
%M arXiv:2409.06914
%P 934 – 940
%D 2025
%X Since the invention of the laser nonlinear effects such as filamentation, Rabi-cycling and collective emission have been explored in the optical regime leading to a wide range of scientific and industrial applications. X-ray free electron lasers (XFELs) have led to the extension of many optical techniques to X-rays for their advantages of angstrom scale spatial resolution and elemental specificity. One such example is XFEL driven population inversion of 1s core hole states resulting in inner-shell Kα (2p to 1s) X-ray lasing in elements ranging from neon to copper, which has been utilized for nonlinear spectroscopy and development of next generation X-ray laser sources. Here we show that strong lasing effects, similar to those observed in the optical regime, can occur at 1.5 to 2.1 angstrom wavelengths during high intensity (> 10<sup>19</sup> W/cm<sup>2</sup>) XFEL driven inner-shell lasing and superfluorescence of copper and manganese. Depending on the temporal substructure of the XFEL pump pulses(containing  10<sup>6</sup> - 10<sup>8</sup> photons) i, the resulting inner-shell X-ray laser pulses can exhibit strong spatial inhomogeneities as well as spectral splitting, inhomogeneities and broadening. Through 3D Maxwell Bloch theory we show that the observed spatial inhomogeneities result from X-ray filamentation, and that the spectral splitting and broadening is driven by Rabi cycling with sub-femtosecond periods. Our simulations indicate that these X-ray pulses can have pulse lengths of less than 100 attoseconds and coherence properties that open the door for quantum X-ray optics applications.
%K Optics (physics.optics) (Other)
%K Atomic Physics (physics.atom-ph) (Other)
%K FOS: Physical sciences (Other)
%F PUB:(DE-HGF)16
%9 Journal Article
%$ pmid:40500439
%R 10.1038/s41586-025-09105-9
%U https://bib-pubdb1.desy.de/record/625317