Fig. 1.

Single-shot pump-probe imaging using femtosecond X-ray laser pulses. A femtosecond IR laser irradiates Au nanoparticles, driving the melting process, and single-pulse XFEL diffraction patterns are collected after planned delays to track the reaction on the picosecond time scale. Single-shot images of nanoparticles undergoing an irreversible melting transition are reconstructed from the diffraction patterns to unveil the ultrafast melting process directly at nanoscale resolution