The optics group is exploring various coherence characterization and wavefront sensing techniques based on grating interferometry and speckle tracking. A state-of-the-art wavefront-sensing technique based on coded-mask technology and deep learning was recently developed [Z. Qiao, X. Shi, M. J. Wojcik, L. Rebuffi, and L. Assoufid, Appl. Phys. Lett. 119, 011105 (2021), DOI: 10.1063/5.0053553]. This fast, high-resolution method is critical for real-time wavefront characterization and monitoring.

A portable interferometer is available as a standard tool for optics testing and beamline wavefront and coherence measurements. It can be operated in multi-modes, including coded-mask-based wavefront sensing, speckle tracking, and grating interferometry. Another compact interferometer is designed for testing diffraction optics such as crystals. Both interferometers are primarily used at the 1-BM beamline [SX1] but could be deployed at other APS beamlines.

We support at-wavelength metrology measurements of X-ray optics, including lenses, mirrors, crystals, and windows. A dedicated system for high-speed characterization of lenses is developed, as shown in the figure above. Thousands of lenses designed for the APS-U beamlines will be tested for quality control