Wavelength-scale ptychographic coherent diffractive imaging using a high-order harmonic source

TL;DR

This paper demonstrates sub-wavelength resolution imaging using a table-top ptychography system with a high-order harmonic XUV source, achieving 45 nm feature resolution and validating its potential for practical scientific and industrial applications.

Contribution

It introduces a high-resolution, table-top ptychography setup utilizing a high-order harmonic source, achieving 2.5 λ resolution and applying a Rayleigh criterion for the first time in this context.

Findings

Achieved 45 nm resolution imaging with table-top ptychography.

Validated the system's capability for real-world applications.

Used Rayleigh criterion as a resolution metric for the first time in this setup.

Abstract

Ptychography enables coherent diffractive imaging (CDI) of extended samples by raster scanning across the illuminating XUV/X-ray beam thereby generalizing the unique advantages of CDI techniques. Table-top realizations of this method are urgently needed for many applications in sciences and industry. Previously, it was only possible to image features much larger than the illuminating wavelength with table-top ptychography although knife-edge tests suggested sub-wavelength resolution. However, most real-world imaging applications require resolving of the smallest and closely-spaced features of a sample in an extended field of view. In this work, we resolve features as small as 2.5 \lambda (45 nm) by using a table-top ptychography setup and a high-order harmonic XUV source. For the first time, a Rayleigh-type criterion is used as a direct and unambiguous resolution metric for high-resolution table-top setup. This reliably qualifies this imaging system for real-world applications e.g. in biological sciences, material sciences, imaging integrated circuits and semiconductor mask inspection.