RESUMEN
Compound optics such as lens systems can overcome the limitations concerning resolution, efficiency, or aberrations which fabrication constraints would impose on any single optical element. In this work we demonstrate unprecedented sub-5 nm point focusing of hard x-rays, based on the combination of a high gain Kirkpatrick-Baez (KB) mirror system and a high resolution W/Si multilayer zone plate (MZP) for ultra-short focal length f. The pre-focusing allows limiting the MZP radius to below 2 µm, compatible with the required 5 nm structure width and essentially unlimited aspect ratios, provided by enabling fabrication technology based on pulsed laser deposition (PLD) and focused ion beam (FIB).
RESUMEN
Alloy-ceramic oxide multilayers of Ni(80)Nb(20)- MgO with 3.56-nm period have been made by use of the pulsed-laser deposition technique and characterized by means of grazing-incidence x-ray reflectivity. The interface roughness was found to be only ~0.35 nm at the two interfaces, Ni(80)Nb(20)- MgO and MgO-Ni(80)Nb(20), leading to a peak reflectivity of ~38% at the first order. The atomic structure in the two individual layers, Ni(80)Nb(20) and MgO, is found to be amorphous, in agreement with the deposition conditions. These multilayers can be used as mirrors for soft x rays in the angular range 18 degrees to 39 degrees , depending on the actual wavelength of radiation in the water-window region.
