Driven by needs from scientific research, healthcare and industrial manufacturing, X-ray microscopy has been successfully transferred from synchrotrons to the laboratory and the spatial resolution has been pushed to sub-micrometer. One way to further improve the resolution is to use an X-ray source with a very small focal spot. At Excillum, based on advanced electron beam and target technologies, a state-of-art nanofocus x-ray tube has been developed which enables an isotropic, resolution of 150 nm line-spacing all the way up to 160 kV of acceleration voltage.

Since more than ten years, MetalJet sources, based on liquid-metal-jet technology [1], are successfully operated in many labs over the world. By using a high-speed jet of liquid metal, instead of the traditional solid- or rotating anode, it has been demonstrated that a much higher power can be applied to the anode. Since melting of the anode is thereby no longer a problem as it is already molten, MetalJet has achieved an at least 10-100x higher brightness than the conventional solid-anode microfocus tube with the X-ray spot size range of 5- 40 µm. Key applications of the MetalJet includes X-ray diffraction and scattering, but several publications have also shown very impressive imaging results using MetalJet technology, especially imaging applications that has traditionally been limited to synchrotron studies – like ptychography [2], X-ray microscopy [3, 4] and phase-contrast imaging [5]. The transfer of these imaging technologies from the synchrotron to the home laboratory are enabled by the high brightness of the MetalJet. During 2021 the latest version of the MetalJet X-ray source, the MetalJet E1+, was introduced which can run up to 1 kW of power at a microfocus X-ray spot (30 µm). This very high power loading enables really fast X-ray imaging, and shows great promise for fast industrial X-ray inspection with high resolution. During the presentation, we will show how we achieved sub-second CT-scans of Li-ion batteries.

At XRnanotech, which is a spin-off company from the Paul Scherrer Institut in Switzerland, we use different nanolithography approaches to structure optical elements down to the single-digit nanometer scale. We use electron-beam nanolithography, two-photon polymerization, direct laser writing and combinations of these techniques to offer outstanding solutions mainly in the field of X-ray optics. Such nanostructured optical elements enable experiments at many large-scale research facilities and are a hot topic in many industries. Our goal is to push the limits of diffractive optics by continuously improving the resolution and efficiency. X-rays are of great interest as these beams offer elemental and chemical sensitivity along with high penetration depth. They represent excellent probes for research and investigation of matter. However, they are challenging to focus using standard refractive optical elements. This is necessary as the ongoing development of accelerator-based photon sources like synchrotrons or X-ray free-electron lasers (XFELs) led to a strong increase in X-ray brilliance over the last decades and enabled ever-new experimental techniques with unprecedented spatial, temporal and spectral resolution. Apart from X-rays, we pursue applications of diffractive optics from infrared to the ultraviolet by exploring new fabrication methods, materials, processes, and designs. We exploit the fact that diffractive optics have a fundamental advantage over other kinds of optical elements like mirrors and refractive lenses, which is the possibility to precisely control and manipulate the optical wave front. This allows realizing complex optical functionalities like beam-shaping optics for X-ray microscopes, spiral zone plates for generating beams with an orbital angular momentum, off axis zone plates that combine microscopy and spectroscopy, beam-splitting zone plates for focusing and beam-splitting as well as achromatic X-ray optical elements [1-6]. In this contribution, we will highlight the latest developments in fabricating diffractive optical elements at XRnanotech aiming at best resolution, efficiency and optical functionality. [1] P R Ribič et al. Phys. Rev. X 24 p. 296 (2018). [2] F. Döring et al. Optica 7 (8), 1007-1014 (2020). [3] B Rösner, et al., Optics Express 25 (2017). [4] I. Vartiainen, et al., Optics Express 23 (2015). [5] B. Rösner et al. Optica 7 (11), 1602-1608 (2020). [6] A. Kubec et al. Nat. Com. (2022).

We demonstrate by rigorous dynamical theory calculations that four-beam diffraction (4BD) can be activated only by a unique photon energy and a unique incidence direction. Thus, 4BD may be used to precisely calibrate X-ray photon energies and beam positions. Based on the principles that the forbidden-reflection 4BD pattern, which is typically an X-shaped cross, can be generated by instant imaging using the divergent beam from a point source without rocking the crystal, we illustrate a detailed real-time high-resolution beam (and source) position monitoring scheme for monitoring two-dimensional beam positions and directions of modern synchrotron light sources, X-ray free-electron lasers and nano-focused X-ray sources. In particular, we will present our recent experiments that exactly verify this theory.

We report on recent developments of solid state based Active X-ray Optics for tailoring the time structure of synchrotron beams at hard x-ray energies. Our contribution presents a full characterization of the SAW-base pulse picking method. Specifically, we show the generation of arbitrary pulse patterns from 100 ns to ms, present data on diffraction efficiency and on/off switching contrast and discuss limits and possibilities for using such optics in coherent beams.

We report on recent developments of solid state based Active X-ray Optics, namely a device that functions as a photoacoustic hard x-ray switch. This so-called PicoSwitch requires a femtosecond laser pulse to trigger the propagation of coherent sound waves to alter the lattice parameter of a specifically designed switching layer in the device heterostructure. The PicoSwitch employs the subsequent angular shift of the diffraction efficiency to slice an impinging synchrotron x-ray pulse to less than 10 ps duration. A major part of the development was carried out at the time-resolved endstation (ID09) of the European Synchrotron Radiation Facility where it is available upon user request. In our contribution we discuss the main operation parameters such as efficiency and on-off switching contrast as well as strategies for improving the device performance even further. In short, the PicoSwitch delivers hard x-ray pulses with a duration of 5-10 ps which are inherently synchronized with the excitation laser. Despite the relatively low efficiency (≈10-3) the device can deliver up to 109 photons/sec when utilized at high repetition rates. In our presentation will discuss benchmark experiments performed at various beamlines, e.g., the investigation of ultrafast lattice dynamics in thin films and superlattices.

High-speed imaging is used to directly visualize various phenomena in material processing such as cutting, electric discharge machining, and laser machining. By using high energy X-rays, phenomena inside materials can be analyzed. In this study, the phenomena of metal drilling were observed using a high-speed imaging system with 100 keV X-rays at SPring-8. Various interesting movies were observed with sub-millisecond order time resolution. In this presentation, we will show the latest results of this research and explain the importance of X-ray high speed imaging in the fields of materials processing.

PZT (lead zirconate titanate)-glued bimorph deformable mirrors are widely used in hard X-ray regimes, however, they have not yet been used in soft X-ray regimes because they are less compatible for usage under high vacuum. Therefore, we have developed a glue-free bimorph deformable mirror, in which silver nanoparticles were employed to bond PZT actuators to mirror substrates. In this study, we manufactured a 400 mm long deformable mirror which has 30 channels on plane mirror surfaces. We evaluated the PZT response by applying voltage to each electrode.