Ultrafast High-Harmonic CDI

Coherent Diffraction Imaging (CDI) combined with pump-probe schemes can yield insight into ultrafast nanoscale dynamics with both high temporal and spatial resolution. With the typical pulse durations of Free-Electron Lasers (FELs) on the order of 100 fs, it is however not possible to resolve electron dynamics in time, which occurr on a sub-femtosecond time scale. While such ultrashort pulses are currently under development at FELs, already today, isolated attosecond XUV pulses and attosecond pulse trains can be generated with high-harmonic-generation (HHG) sources. But these pulses are typically weaker than FELs by orders of magnitude.

In a favorable combination of experimental parameters, we could recently demonstrate single-particle single-shot diffractive imaging of individual helium nanodroplets with high-intensity HHG pulses (external page Rupp 2017). The results of this experiment, combined with the rapid development of intense HHG sources, provide a promising pathway to map excitation and charge separation processes in nanoscale matter on their natural time scale.