Reconstructing longitudinal strain pulses using time-resolved x-ray diffraction

Time-resolved x-ray diffraction is a very powerful tool for visualizing transient one-dimensional crystalline strains, ranging from crystal growth to shock wave 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.