Ion beam lithography for Fresnel zone plates in X-ray microscopy

TL;DR

This paper demonstrates that ion beam lithography can effectively simplify the fabrication of Fresnel zone plates for X-ray microscopy, achieving high resolution and efficiency comparable to traditional methods.

Contribution

It introduces ion beam lithography as a novel, advantageous method for fabricating Fresnel zone plates with high precision and efficiency.

Findings

FZPs operable from UV to hard X-ray range were successfully fabricated.

FZPs with 100 nm outermost zone width visualize features down to 21 nm.

Measured efficiencies match theoretical predictions.

Abstract

Fresnel Zone Plates (FZP) are to date very successful focusing optics for X-rays. Established methods of fabrication are rather complex and based on electron beam lithography (EBL). Here, we show that ion beam lithography (IBL) may advantageously simplify their preparation. A FZP operable from the extreme UV to the limit of the hard X-ray was prepared and tested from 450 eV to 1500 eV. The trapezoidal profile of the FZP favorably activates its 2nd order focus. The FZP with an outermost zone width of 100 nm allows the visualization of features down to 61, 31 and 21 nm in the 1st, 2nd and 3rd order focus respectively. Measured efficiencies in the 1st and 2nd order of diffraction reach the theoretical predictions.