Wavefront sensing and characterization for X-ray free electron lasers

Precise wavefront information is essential for optimizing nano-focusing, as it affects the focal spot size, shape, and stability. This requires wavefront sensing methods that are single-shot, sensitive, robust under high flux, and compatible with both collimated and focused beams. To fully characterize the FEL beam, measurements at different locations—such as after the undulator, transport optics, and at the sample—are needed. While SHINE Project is still under construction, we have already built and tested a single-grating Talbot interferometry setup at SXFEL, which meets these requirements and supports future applications in X-ray FEL.