Single-pulse phase-contrast imaging at free-electron lasers in the hard X-ray regime
| Autor: | Robert Schaffer, Anders Madsen, Tim Salditt, Ulrike Boesenberg, Andreas Schropp, Jörg Hallmann, Roman Shayduk, Markus Osterhoff, Juan Manuel Rosselló, Chan Kim, Alexey Zozulya, Johannes Hagemann, Markus Scholz, M. Vassholz, Wei Lu, Hannes Paul Hoeppe, Frank Seiboth, Robert Mettin, Johannes Möller, Christian G. Schroer |
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| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
Nuclear and High Energy Physics
phase problem Holography Physics::Optics phase contrast X-ray imaging 02 engineering and technology Phase problem 01 natural sciences diffract-then-destroy law.invention 010309 optics Optics law 0103 physical sciences ddc:550 X-ray microscopy Spontaneous emission Instrumentation Physics Wavefront Jet (fluid) Radiation business.industry sample delivery Phase-contrast X-ray imaging Phase-contrast imaging 021001 nanoscience & nanotechnology Laser Research Papers 3. Good health XFELs dynamical studies pump–probe 0210 nano-technology business |
| Zdroj: | Journal of synchrotron radiation 28(1), 52-63 (2021). doi:10.1107/S160057752001557X Journal of Synchrotron Radiation |
| DOI: | 10.1107/S160057752001557X |
| Popis: | XFEL radiation based on the stochastic SASE principle can be described by a low-dimensional configuration space. This space of pulse shapes can be sufficiently sampled before an imaging experiment. This approach is used to implement near-field holography of dynamic processes, demonstrated for the example of a micro-fluidic jet illuminated by the divergent wavefront emanating from a compound refractive lens nano-focus. Droplet formation in the break-up regime of the jet, as well as the hydrodynamic phenomena following plasma generation by an intense infrared laser pulse, can be imaged, based on flat-field corrected holograms and subsequent phase retrieval. X-ray free-electron lasers (XFELs) have opened up unprecedented opportunities for time-resolved nano-scale imaging with X-rays. Near-field propagation-based imaging, and in particular near-field holography (NFH) in its high-resolution implementation in cone-beam geometry, can offer full-field views of a specimen’s dynamics captured by single XFEL pulses. To exploit this capability, for example in optical-pump/X-ray-probe imaging schemes, the stochastic nature of the self-amplified spontaneous emission pulses, i.e. the dynamics of the beam itself, presents a major challenge. In this work, a concept is presented to address the fluctuating illumination wavefronts by sampling the configuration space of SASE pulses before an actual recording, followed by a principal component analysis. This scheme is implemented at the MID (Materials Imaging and Dynamics) instrument of the European XFEL and time-resolved NFH is performed using aberration-corrected nano-focusing compound refractive lenses. Specifically, the dynamics of a micro-fluidic water-jet, which is commonly used as sample delivery system at XFELs, is imaged. The jet exhibits rich dynamics of droplet formation in the break-up regime. Moreover, pump–probe imaging is demonstrated using an infrared pulsed laser to induce cavitation and explosion of the jet. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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