Measurement of transient strain induced by two-photon excitation

This paper quantifies the lattice expansion of an insulator upon two photon excitation. The ultrafast x-ray diffraction experiments measure a clean quadratic dependence of the strain on the laser fluency and prove that the pulse intensity is the relevant quantity, as the signal is anti-proportional to the pulse duration. The investigated material Bi:YIG is the standard material for magnonics, where ultrashort laser-pulses can create spin-waves via various mechanisms, including strain modulation of the anisotropy