Xuv Gratings Based On Holography

In addition to applications based on particle accelerator sources the XUV wavelength range is interesting for several further fields of research - for example in astronomy. On one hand, due to the short wavelengths a diffraction grating for these applications must provide a high-quality surface figure of its polished grating substrate or blank. On the other hand, the grating profile must be very smooth with no relevant phase errors to provide high diffraction efficiency as well as minimum stray light levels. Due to these challenging specifications it is advantageous if a manufacturer has access to lithographic technologies and sophisticated polishing processes at once. For instance, it is sometimes crucial to adapt the polishing to the employed technology chain in order to reach optimum grating performance. Furthermore, a capable grating manufacturing technology should enable flexible line distributions ranging from equally spaced lines on plane or curved substrates up to variable-line-spacing gratings (VLS) as well as even curved lines for imaging grating types in general. Grating surface figures ranging from plane, spherical and cylindrical up to freeform and - in case of beamline optics for grazing incidence operation mode - comparable massive grating blanks must be manageable as well. By employing holographic exposure in combination with new and state-of-the-art etching techniques it is feasible to address all the mentioned features. We will address the degrees of freedom in grating design arising due to holographic pattern definition and present latest improvements that go beyond the so far reported status of XUV grating manufacturing. Beside the flexibility of holography to achieve excellent roughness and best peak efficiency on silicon the option for local blaze adaption can be extremely beneficial. Thus, it will be in the focus of this text.