Full-field X-ray microscopy with crossed partial multilayer Laue lenses

Abstract

Abstract:We demonstrate full-field X-ray microscopy using crossed multilayer Laue lenses (MLL). Two partial MLLs are prepared out of a 48 µm high multilayer stack consisting of 2451 alternating zones of WSi 2 and Si. They are assembled perpendicularly in series to obtain two-dimensional imaging. Experiments are done in a laboratory X-ray microscope using Cu-Kα radiation (E = 8.05 keV, focal length f = 8.0 mm). Sub-100 nm resolution is demonstrated without mixed-order imaging at an appropriate position of the image plane. Although existing deviations from design parameters still cause aberrations, MLLs are a promising approach to realize hard X-ray microscopy at high efficiencies with resolutions down to the sub-10 nm range in future.

A dedicated illumination for full-field X-ray microscopy with multilayer Laue lenses

“…The initial experimental setup consists of  a microfocus X-ray source with a Cu anode and a Ø 50 µm X-ray focus operated at 50 kV and 0.8 mA,  a two-dimensionally focusing X-ray multilayer mirror for Cu Kα radiation with a maximum NA of 0.010,  crossed partial MLLs with a focal length of 8.0 mm for Cu Kα radiation [10,11], and  a commercial, fan cooled X-ray detector with 6.45 µm pixel size.…”

“…The image is generated in the corresponding quadrant of the image plane. It can be separated from other diffraction orders at this position [11]. This implies that no hollow cone illumination is required.…”

“…These serial diffractive lenses consist of two individual partial MLLs assembled in close distance perpendicularly to each other. Focus matching is achieved by combining two partial MLLs with slightly different focal lengths [11]. The transmitted X-rays of each MLL are scattered to multiple diffraction orders and the effects of both MLLs superimpose.…”

“…The remaining parts of the X-rays (1-1) are diffracted by both MLLs and generate the image of the specimen. The image is adequately separated from other orders, since partial MLLs are applied [11]. An equivalent approach is performed for point focusing of synchrotron radiation [14].…”

“…It was demonstrated that crossed partial MLLs can be applied to full-field X-ray microscopy [11], if the optical path is modified accordingly. A commercially available X-ray microscope using a Cu rotating anode was modified for these experiments, i.e.…”