Tunable hard x-ray nanofocusing with Fresnel zone plates fabricated using deep etching

Kenan Li, Sajid Ali, Michael Wojcik, Vincent de Andrade, Xiaojing Huang, Hanfei Yan, Yong S. Chu, Evgeny Nazaretski, Ajith Pattammattel, Chris Jacobsen*

*Corresponding author for this work

Research output: Contribution to journalArticle

2 Scopus citations

Abstract

Fresnel zone plates are used widely for x-ray nanofocusing, due to their ease of alignment and energy tunability. Their spatial resolution is limited in part by their outermost zone width drN, while their efficiency is limited in part by their thickness tzp. We demonstrate the use of Fresnel zone plate optics for x-ray nanofocusing with drN = 16 nm outermost zone width and a thickness of about tzp = 1.8 µm (or an aspect ratio of 110) with an absolute focusing efficiency of 4.7% at 12 keV, and 6.2% at 10 keV. Using partially coherent illumination at 12 keV, the zone plate delivered a FWHM focus of 46 × 60 nm at 12 keV, with the first-order coherent mode in a ptychographic reconstruction showing a probe size of 16 nm FWHM. These optics were fabricated using a combination of metal-assisted chemical etching and atomic layer deposition for the diffracting structures, and silicon wafer back-thinning to produce optics useful for real applications. This approach should enable new higher resolution views of thick materials, especially when energy tunability is required.

Original languageEnglish (US)
Pages (from-to)410-416
Number of pages7
JournalOptica
Volume7
Issue number5
DOIs
StatePublished - May 25 2020

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics

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    Li, K., Ali, S., Wojcik, M., de Andrade, V., Huang, X., Yan, H., Chu, Y. S., Nazaretski, E., Pattammattel, A., & Jacobsen, C. (2020). Tunable hard x-ray nanofocusing with Fresnel zone plates fabricated using deep etching. Optica, 7(5), 410-416. https://doi.org/10.1364/OPTICA.387445