\label{figDepEnergy} Experimentally measured amplitude of the shear wave versus laser beam power (log-log scale). Two linear dependencies are observed: one from 10 to 40 mJ (slope of 1.05), and one from 30 to 200 mJ (slope of 2.18). Four displacement maps at t = 2.0 ms are illustrated, for laser beam energies of 10, 30, 80 and 200 mJ. At low energy, a third half cycle is observed, which disappears when energy increases.