Soft X-ray imaging with coherence tomography in the water window spectral range using high-harmonic generation
High-harmonic generation (HHG) is used as a source for various imaging applications in the extreme ultraviolet spectral range. It offers spatially coherent radiation and unique elemental contrast with the potential for attosecond time resolution. The unfavorable efficiency scaling to higher photon energies prevented the imaging application in the soft X-ray range so far. In this work we demonstrate the feasibility of using harmonics for imaging in the water window spectral region (284 eV to 532 eV). We achieve nondestructive depth profile imaging in a heterostructure by utilizing a broadband and noise-resistant technique called soft X-ray Coherence Tomography (SXCT) at a high-flux lab-scale HHG source. SXCT is derived from Optical Coherence Tomography, a Fourier based technique that can use the full bandwidth of the source to reach an axial resolution of 12 nm in this demonstration. The employed source covers the entire water window, with a photon flux exceeding 10<sup>6</sup> photons/eV/s at a photon energy of 500 eV. We show local cross sections of a sample consisting of Aluminium oxide and Platinum layers of varying thickness on a Zinc oxide substrate. We validate the findings with scanning and transmission electron microscopy after preparation with focused ion beam milling.
Authors
- Sophia Kaleta (ORCID: https://orcid.org/0009-0009-7211-2638)
- Martin Wünsche (ORCID: https://orcid.org/0000-0002-1090-8018)
- Stephanie Lippmann (ORCID: https://orcid.org/0000-0002-8250-4696)
- Julius Reinhard (ORCID: https://orcid.org/0000-0002-5761-4340)
- M. Schnürer
- Jonathan Plentz (ORCID: https://orcid.org/0000-0003-1176-0710)
- Felix Wiesner (ORCID: https://orcid.org/0000-0001-5352-9205)
- Gabriele Schmidl (ORCID: https://orcid.org/0000-0003-0738-1515)
- G. G. Paulus (ORCID: https://orcid.org/0000-0002-8343-8811)
- Johann J. Abel
- Silvio Fuchs (ORCID: https://orcid.org/0000-0002-3246-2627)
- Katharina Freiberg (ORCID: https://orcid.org/0000-0001-8821-4529)
- Themistoklis P. H. Sidiropoulos (ORCID: https://orcid.org/0000-0003-3305-3750)
- M. Hennecke (ORCID: https://orcid.org/0000-0003-0826-6471)
- Jonathan Apell (ORCID: https://orcid.org/0000-0001-6038-3005)
- Julian Späthe (ORCID: https://orcid.org/0009-0009-6593-4916)
- Uwe Hübner
- Stefan Eisebitt
Institutions
- Hochschule Mittweida (DE)
- Helmholtz Institute Jena (DE)
- Chemnitz University of Technology (DE)
- Leibniz Institute of Photonic Technology (DE)
- Electro Optical Systems (Germany) (DE)
- Max-Born-Institute for Nonlinear Optics and Short Pulse Spectroscopy (DE)
- Technische Universität Berlin (DE)
- Friedrich Schiller University Jena (DE)
Publication Details
- Journal
- Light Science & Applications
- Published
- 2026-01-22
- DOI
- https://doi.org/10.1038/s41377-025-02057-9
- Citations
- 1
- Primary Topic
- Advanced X-ray Imaging Techniques
- Type
- article
- Field-Weighted Citation Impact
- 47.32
Funders
- Deutsche Forschungsgemeinschaft
- Bundesministerium für Bildung und Forschung
- Thüringer Aufbaubank
- Leibniz-Gemeinschaft
- European Regional Development Fund
- European Social Fund