Three-dimensional structured on-chip stacked zone plates for nanoscale X-ray imaging with high efficiency

• Published in: Nano research Vol. 7; no. 4; pp. 528 - 535
• Main Authors: Werner, Stephan, Rehbein, Stefan, Guttmann, Peter, Schneider, Gerd
• Format: Journal Article
• Language: English
• Published: Heidelberg Tsinghua University Press 01.04.2014; Springer Nature B.V
• Subjects: Atomic/Molecular Structure and Spectra; Beams (radiation); Biomedicine; Biotechnology; Chemistry and Materials Science; Condensed Matter Physics; Efficiency; Focusing; Fresnel zones; Materials Science; Microscopy; Nanostructure; Nanotechnology; Optics; Research Article; Spatial resolution; Three dimensional; X-rays; X射线成像; Zone plates; 三维结构; 上层; 光学器件; 叠带; 纳米级; 菲涅耳波带片; 高空间分辨率; Fresnel zone plates; X-ray microscopy; X-ray imaging; X-ray optics; volume diffraction
• ISSN: 1998-0124; 1998-0000
• DOI: 10.1007/s12274-014-0419-x

Fresnel zone plates are the key optical elements for nanoscale focusing of X-ray beams with high spatial resolution. Conventional zone plates manufactured by planar nanotechnology processes are limited by the achievable aspect ratios of their zone structures. Additionally, ultra-high resolution X-ray optics with high efficiency requires three-dimensional （3-D） shaped tilted zones. The combination of high spatial resolution and high diffraction efficiency is a fundamental problem in X-ray optics. Based on electrodynamical simulations, we find that the optimized zone plate profile for volume diffraction is given by zone structures with radially increasing tilt angles and decreasing zone heights. On-chip stacking permits the realization of such advanced 3-D profiles without significant loss of the maximum theoretical efficiency. We developed triple layer on-chip stacked zone plates with an overlay accuracy of sub-2 nm which fulfills the nanofabrication requirements. Efficiency measurements of on-chip stacked zone plates show significantly increased values compared to conventional zone plates.