Time-resolved x-ray diffraction is a very powerful tool for visualizing transient one-dimensional crystalline strains, ranging from crystal growth to shockwave production. In this work, we use picosecond x-ray diffraction to visualize transient strain formation from nanometer scaled laser excited gold films into crystalline substrates. We show that there is a direct correspondence between the measured time-resolved x-ray diffraction pattern and the transient acoustic wave, providing a straightforward method to make a reconstruction of the transient strain. In addition, we discuss real-world experimental constraints that place limits on the validity of the reconstructed transient acoustic wave.

Designing an efficient and simple method for modulating the intensity of x-ray radiation on a picosecond time-scale has the potential to produce ultrafast pulses of hard x-rays. In this work, we generate a tunable transient superlattice, in an otherwise perfect crystal, by photoexciting a metal film on a crystalline substrate. The resulting transient strain has amplitudes approaching 1%, wavevectors greater than 0.002 Å−1, and lifetimes approaching 1 ns. This method has the potential to generate isolated picosecond x-ray bursts with scattering efficiencies in excess of 10%.

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