# Pulse-to-pulse wavefront sensing at free-electron lasers using ptychography

## TL;DR

This paper introduces a ptychography-based method for pulse-to-pulse wavefront sensing in free-electron lasers, enabling high-resolution, diffraction-limited characterization of individual ultra-short pulses in their native imaging state.

## Contribution

The paper presents a novel lensless ptychography technique capable of retrieving complex wave functions of FEL pulses at high resolution, suitable for native diffraction conditions.

## Key findings

- Achieves diffraction-limited resolution in wavefront sensing
- Successfully retrieves complex wave functions of individual pulses
- Applicable to various short-pulse instruments

## Abstract

The pressing need for the detailed wavefront properties of ultra-bright and ultra-short pulses produced by free-electron lasers (FELs) has spurred the development of several complementary characterization approaches. Here we present a method based on ptychography that can retrieve full high-resolution complex-valued wave functions of individual pulses. Our technique is demonstrated within experimental conditions suited for diffraction experiments in their native imaging state. This lensless technique, applicable to many other short-pulse instruments, can achieve diffraction-limited resolution.