Expansion Dynamics after Laser-Induced Cavitation in Liquid Tin Microdroplets

The cavitation-driven expansion dynamics of liquid tin microdroplets set in motion by the ablative impact of a 15-ps laser pulse is investigated. We combine high-resolution stroboscopic shadowgraphy with an intuitive fluid-dynamic model that includes the onset of fragmentation, and find good agreement between model and experimental data for two different droplet sizes over a wide range of laser pulse energies. The dependence of the initial expansion velocity on these experimental parameters is heuristically captured in a single power law. Further, the late-time mass distributions obtained are shown to be governed by a single parameter. These studies are performed under conditions relevant for plasma light sources for extreme-ultraviolet nanolithography.