High-resolution ptychographic nanoimaging under high pressure with X-ray beam scanning

TL;DR

A new X-ray imaging technique allows high-resolution nanoimaging of materials under extreme pressure by scanning the X-ray beam instead of the sample.

Contribution

The novel beam-scanning ptychography approach enables high-resolution imaging in heavy or bulky sample environments previously unachievable.

Findings

Beam-scanning ptychography achieves sub-50 nm resolution and high sensitivity under extreme pressure.

The method successfully visualized iron oxidation and melting at 50 GPa using diamond anvil cells.

This technique overcomes limitations of traditional methods in handling heavy sample environments.

Abstract

We demonstrate a novel approach to X-ray ptychography, a phase-sensitive scanning microscopy method. By replacing the conventional sample scanning approach with a beam-scanning via reflective optics, we expand the capabilities of nanoimaging for heavy/bulky sample environments, e.g., under extreme pressure. Our approach eliminates the major limitation of previous methods: the necessity to translate the sample. This long hindered high-resolution imaging in environments such as diamond anvil cells. By steering the X-ray beam, we enabled visualization of pressure-driven reactions (e.g., iron oxidation at 50 GPa) with the highest sensitivity and sub-50 nm resolution. This breakthrough opens an avenue for operando nanoscopy, benefiting many scientific fields, such as geoscience, materials synthesis, and high-pressure physics, where static imaging methods fall short.

We present an approach to nanoscale-resolution high-sensitivity imaging of internal material structure under in situ/operando conditions for virtually any sample environment. When bulky or heavy sample environment is required state-of-the-art X-ray imaging techniques, such as scanning and full-field microscopy or holography fail to deliver high-resolution imaging capabilities due to either i) extremely small optics’ working distance for magnification-based methods or ii) the inability to precisely control heavy sample position in the case of lens-less methods. In this work, we address those challenges for a scanning lens-less imaging method called ptychography. Instead of precisely controlling the sample position during raster scan in a focused, confined X-ray beam, we are scanning that beam across the sample. This overcomes the constraints on scanning procedure imposed by sample size/weight and delivers unmatched scanning speed while maintaining high precision of beam position during the scan. We directly applied our approach, showcasing phase contrast nanoimaging with diamond anvil cells, and visualized intricate details of the melting and oxidation of laser-irradiated iron under pressure of 50 GPa.

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