3D Nanofabrication of High‐Resolution Multilayer Fresnel Zone Plates

Abstract

Focusing X‐rays to single nanometer dimensions is impeded by the lack of high‐quality, high‐resolution optics. Challenges in fabricating high aspect ratio 3D nanostructures limit the quality and the resolution. Multilayer zone plates target this challenge by offering virtually unlimited and freely selectable aspect ratios. Here, a full‐ceramic zone plate is fabricated via atomic layer deposition of multilayers over optical quality glass fibers and subsequent focused ion beam slicing. The quality of the multilayers is confirmed up to an aspect ratio of 500 with zones as thin as 25 nm. Focusing performance of the fabricated zone plate is tested toward the high‐energy limit of a soft X‐ray scanning transmission microscope, achieving a 15 nm half‐pitch cut‐off resolution. Sources of adverse influences are identified, and effective routes for improving the zone plate performance are elaborated, paving a clear path toward using multilayer zone plates in high‐energy X‐ray microscopy. Finally, a new fabrication concept is introduced for making zone plates with precisely tilted zones, targeting even higher resolutions.

In Situ Probing Multiple‐Scale Structures of Energy Materials for Li‐Ion Batteries

“…The major challenge for in operando STXM measurement is the long data acquisition time, and especially the vacuum condition required for XFM further limits the in situ operation. With the advances of synchrotron X‐ray sources, focusing optics, and detectors, the speed of data collection has been accelerated . Nowadays, the in situ STXM and XFM techniques have shown their unique power for monitoring chemical and structural dynamics of energy materials and undoubtedly will take a greater role in the future battery researches.…”

3D Nanoprinted Plastic Kinoform X‐Ray Optics

“…However, diffraction efficiencies were predicted to be less than a percent, owing to the challenges in fabricating high‐aspect‐ratio structures . Moreover, decreasing the outermost zone width of the FZP without changing the geometry has repeatedly been shown to be an ineffective strategy to improve the resolving power . To overcome this seemingly dead‐end, new imaging modalities, namely, coherent diffractive imaging (CDI) techniques have emerged.…”

High-throughput synthesis of modified Fresnel zone plate arrays via ion beam lithography

“…The parasitic deposition layer, where a Pt/C layer deposits unintentionally on the regions adjacent to the actual region of interest, covers the zones with a thin layer of platinum/gallium/carbon mixture (see Supporting Information File 1 , Figure S3), which absorbs incident X-rays and leads to a decrease in light transmission and hence, the efficiency. The extent of the parasitic deposition and its impact on the DE is discussed in more detail elsewhere [ 45 ].…”