Ptychographic X-ray speckle tracking with multi-layer Laue lens systems

Area of Science:

• Optics and Photonics
• Materials Science
• Biophysics

Background:

• Advancements in synchrotron radiation sources necessitate improved X-ray optics for nanoscale imaging and probing.
• Hard X-rays offer high resolution and chemical sensitivity but are challenging to focus due to their penetrating power.
• Wedged multi-layer Laue lenses represent a significant development in X-ray focusing technology.

Purpose of the Study:

• To develop an accurate, robust, in situ, and at-wavelength characterization method for advanced X-ray lenses.
• To validate a novel wavefront metrology technique for evaluating X-ray optical components.

Main Methods:

• Development of a modified speckle tracking wavefront metrology method, termed ptychographic X-ray speckle tracking.
• The method is designed to operate with highly divergent wavefields and is robust to sample positioning errors.
• Utilizes X-ray speckle patterns to reconstruct wavefront information and assess lens performance.

Main Results:

• Achieved high-precision measurement of ray path angles within 4 nrad.
• Demonstrated high-resolution imaging capabilities with a resolution of 45 nm (full period).
• The method provides aberration-free projection images of extended specimens as a secondary outcome.

Conclusions:

• The ptychographic X-ray speckle tracking method is suitable for characterizing advanced X-ray optics, including wedged multi-layer Laue lenses.
• Its ability to work with low coherence sources and its robustness make it applicable to both laboratory X-ray sources and X-ray free-electron laser facilities.
• This characterization technique is crucial for advancing nanoscale imaging and spectroscopic applications in various scientific fields.