X-ray Optics and Applications
Interferometric imaging techniques using hard x-rays also rely on specialized micro-fabricated gratings. The possibility to use this technique not only with synchrotron radiation but also with incoherent x-rays from tube sources makes the technique interesting for commercial applications. The extreme sensitivity of grating interferometry also provides a powerful tool for x-ray optics metrology and wavefront sensing.
The development of a new generation of x-ray sources based on the x-ray free-electron laser (X-FEL) principle have triggered the development of specialized diffractive optics. In order to withstand the extreme power levels of X-FELs, we make Fresnel zone plates based on diamond substrates. Similar devices are made for applications such as spectral monitoring or beam splitting. The latter is used to build multiple split-and-delay lines for ultra-fast pump-probe experiments with unprecedented timing precision.
For the fabrication of these devices, the X-Ray Optics and Applications Group runs LMN’s high performance electron-beam lithography tool Vistec EBPG 5000PlusES, that is also used by many other internal and external research groups.
For references of the X-Ray Optics Group (since 2005) see: DORA
The Innovation Award on Synchrotron Radiation 2018 went to Dr. Christian David from the Paul Scherrer Institute, and to Prof. Alexei Erko, who recently moved from the HZB to the Institute for Applied Photonics (IAP) in Berlin-Adlershof.
The spot size of a Fresnel Zone Plate lens is mainly determined by the zone widths of its outermost zone. It is therefore essential to fabricate zone plates with structures as small as possible for high-resolution X-ray microscopy. Researchers at the Laboratory for Micro- and Nanotechnology at the PSI have now developed Fresnel zone plates with zone widths well below 10 nm, down to 6.4 nm. These lenses are capable of pushing resolution in X-ray microscopy to the single-digit regime.
The advent of x-ray free electron lasers has extended the unique capabilities of resonant x-ray spectroscopy techniques to ultrafast time scales. Here, in collaboration between researchers from PSI, Sorbonne Universités, HASYLAB/DESY, Synchrotron SOLEIL, CNRS, and Uppsala University, we report on a novel experimental method that allows retrieving with a single x-ray pulse the time evolution of an ultrafast process, not only at a few discrete time delays, but continuously over an extended time window.