Dr. Christian David

Christian David is Group Head of X-Ray Nano-Optics at the Laboratory for X-ray Nanoscience and Technologies (LXN), Photon Science Division of the Paul Scherrer Institut. He was born in Den Haag, Netherlands, in 1965. He received his Diploma in Physics in 1989 and his PhD in 1993 from the Georg-August-University of Göttingen, Germany. After a postdoctoral stay at the Ruprecht-Karls-University of Heidelberg, Germany, working on the application of organic self-assembled monolayers in nanolithography, he joined LMN in 1996, to work on the nanofabrication of optical and electronic devices by electron-beam lithography. In 2002, he became Head of the X-Ray Nano-Optics at LXN. The devices and methods developed by his group are applied at many large scale research facilities in photon science all over the world. Christian David is author or coauthor of more than 350 peer reviewed scientific publications (H-index 69) and holds 15 patents. He is member of several international scientific committees. Most prominently, he is currently the chair of the Photon Science Committee advising the DESY research center in Hamburg on activities in the field of synchrotron and x-ray laser research. He was awarded the Röntgen Prize by the Justus-Liebig-University of Giessen for his work on x-ray phase contrast imaging (2010) and the Innovationspreis Synchrotronstrahlung by the Helmholtz-Zentrum Berlin (2018) for his developments in diffractive X-ray optics.

Christian David is Deputy Head of the Laboratory for X-ray Nanoscience and Technologies (LXN) and supports the Head of the Laboratory in strategic, organizational matters. He is member of several international scientific committees in photon science. Most prominently, he is currently the chair of the Photon Science Committee advising the DESY research center in Hamburg on activities in the field of synchrotron and x-ray laser research. During his scientific career, he has supervised more than 20 PostDoctoral Researchers and more than 15 Masters and PhD students.

David’s research focuses on applying micro- and nanofabrication techniques for advanced X-ray optics, imaging techniques, and instrumentation for synchrotrons and X-ray free-electron lasers. This includes: the fabrication of diffractive x-ray lenses with extreme resolution, very high efficiency, or complex optical functionality, gratings for x-ray wavefront metrology and phase contrast imaging,  and energy dispersive diffractive elements for advanced X-ray spectroscopy techniques. More recently, his research interest has extended towards beam splitting and time dispersive diffractive optics for experiments in ultra-fast science at X-Ray Free-Electron Lasers.

An extensive overview of Christian David’s publications can be found here:

Selected Publications:

An Achromatic X-ray Lens, A. Kubec, M.-C. Zdora, U. Sanli, A. Diaz, J. Vila-Comamala, C. David, Nature Communications 13 (2022) p. 1305, DOI: 10.1038/s41467-022-28902-8. Diffractive and refractive optical elements have become an integral part of most high-resolution X-ray microscopes. However, they suffer from inherent chromatic aberration. This has to date restricted their use to narrow-bandwidth radiation, essentially limiting such high-resolution X-ray microscopes
to high-brightness synchrotron sources. We report on the first successful experimental realisation of an X-ray achromat, consisting of a focusing diffractive Fresnel zone plate and a defocusing refractive lens, providing sub-micrometre achromatic focusing over a wide energy range without any focal adjustment. This type of X-ray achromat will overcome previous limitations set by the chromatic aberration of diffractive and refractive optics and paves the way for new
applications in spectroscopy and microscopy at broadband X-ray tube sources.

Double Frequency Shearing Interferometry for X-ray Free Electron Laser beams, M. Makita, G. Seniutinas, M.H. Seaberg, H.J. Lee, E.C. Galtier, M. Liang, A. Aquila, S. Boutet, A. Hashim, M. Hunter, T. van Driel, U. Zastrau, C. David, and B. Nagler, Optica 7 (2020) p. 404, DOI: 10.1364/OPTICA.390601. The X-ray wave front measurements described in this publication are based on diamond diffraction gratings with nanoscale structures. They are used in a single shot shearing interferometry method to characterize nanofocused X-ray pulses from an X-ray Free-Electron Laser. The method is non-invasive meaning that the transmitted pulse is not modified in intensity or profile, providing a fully characterized pulse for general experimental use.

Single Shot Time Resolved Magnetic Absorption at Free Electron Laser, E. Jal, M. Makita, B. Rösner, C. David, F. Nolting, J. Raabe, T. Savchenko, A. Kleibert, F. Capotondi, E. Pedersoli, X. Liu, A. el dine Merhe, N. Jaouen, G. Malinowski, M. Hehn, B. Vodungbo, and J. Lüning, Physical Review B 99 (2019) p. 144305-9, DOI: 10.1103/PhysRevB.99.144305 Ultrafast dynamics are generally investigated using stroboscopic pump-probe measurements, which characterize the sample properties for a single, specific time delay. These measurements are then repeated for a series of discrete time delays to reconstruct the time trace of the process. As a consequence, this approach is limited to the investigation of fully reversible phenomena. We recently introduced an off-axis zone plate based x-ray streaking technique, which overcomes this limitation by sampling the relaxation dynamics with a single femtosecond x-ray pulse streaked over a picosecond long time window. We show that the ultrafast magnetization dynamics in CoDy alloy films can be resolved with this method. Our experimental findings indicate that the demagnetization time is independent of the specific infrared laser pump fluence. These results pave the way for the investigation of irreversible phenomena in a wide variety of scientific areas.

Transmission zone plates as analyzers for efficient RIXS-mapping, F. Marschall, Z. Yin, J. Rehanek, M. Beye, F. Döring, K. Kubicek, D. Raiser, S. Thekku Veedu, J. Buck, A. Rothkirch, B. Rösner, V.A. Guzenko, J. Viefhaus, C. David, and S. Techert, Scientific Reports 7 (2017) p. 8849, DOI: 10.1038/s41598-017-09052-0, We have developed a new spectral analyzer scheme for resonant inelastic X-ray scattering (RIXS) based on off-axis transmission Fresnel zone plates. It combines energy-dispersive properties with imaging capability. By varying the incident photon energy along a line focus on the sample, it is now possible to simultaneously record the emission spectra of a sample over a range of excitation energies, providing a map of RIXS spectra in a single exposure. Moreover, the new optical component allow for RIXS imaging of samples with at least two orders of magnitude improved efficiency.