Abstract
- Short-wavelength radiation in the extreme ultraviolet (XUV) and soft x-ray spectral regions offers unique advantages for imaging. With wavelengths ranging from a few nanometers to a few tens of nanometers, these techniques enable spatial resolutions at the nanometer scale. In addition, penetration depths in solids in this spectral regime enable non-destructive imaging of internal structures of micrometer-thick objects, surpassing the capabilities of electron microscopy. Furthermore, the diverse atomic absorption edges characteristic of this spectral region enable high-contrast imaging without any staining or labeling. When combined with quantitative phase-sensitive imaging techniques, even material identification at the nanoscale becomes feasible. This article reviews some of the latest advancements in the field. It provides an overview of the available tabletop sources in this spectral region and discusses concepts and state-of-the-art results of two complementary imaging techniques: XUV ptychography and XUV coherence tomography. While XUV ptychography achieves nanoscale lateral resolution, XUV coherence tomography enables nanoscale axial resolution. Both techniques allow for the non-destructive mapping of the chemical composition of samples, facilitating localized analysis of material compositions in integrated circuits or microorganisms. The article also presents a perspective on future developments in time-resolved and 3D XUV imaging and potential future application fields.