Fabrication and characterization of ultra-high resolution multilayer-coated blazed gratings

Multilayer-coated blazed gratings with high groove density are the most promising candidates for ultra-high resolution soft X-ray spectroscopy. They combine the ability of blazed gratings to concentrate almost all diffraction energy in a desired high diffraction order with high reflectance soft X-ray multilayers. However in order to realize this potential, the grating fabrication process should provide a near perfect groove profile with an extremely smooth surface of the blazed facets. Here we report on the successful fabrication and testing of ultra-dense saw-tooth substrates with 5000 and 10,000 lines/mm.