Nanometer Linear Focusing of Hard X Rays by a Multilayer Laue Lens

TLDR

Because of its large optical depth, a multilayer Laue lens spans the diffraction regimes applicable to a thin Fresnel zone plate and a crystal. The authors report a linear zone plate for nanometer‑scale focusing of hard X‑rays—a multilayer Laue lens produced by sectioning a multilayer and illuminating it in Laue diffraction geometry. The MLL is fabricated by sectioning a multilayer and illuminating it in Laue diffraction geometry, and partial structures with outermost zone widths as small as 10 nm have been tested with 19.5 keV synchrotron radiation. Coupled‑wave theory predicts focusing to 5 nm or smaller with high efficiency, and measured focal sizes as small as 30 nm with efficiencies up to 44 % confirm this capability.

Abstract

We report on a type of linear zone plate for nanometer-scale focusing of hard x rays, a multilayer Laue lens (MLL), produced by sectioning a multilayer and illuminating it in Laue diffraction geometry. Because of its large optical depth, a MLL spans the diffraction regimes applicable to a thin Fresnel zone plate and a crystal. Coupled wave theory calculations indicate that focusing to 5 nm or smaller with high efficiency should be possible. Partial MLL structures with outermost zone widths as small as 10 nm have been fabricated and tested with 19.5 keV synchrotron radiation. Focal sizes as small as 30 nm with efficiencies up to 44% are measured.