High fidelity visualization of multiscale dynamics of laser-induced bubbles in liquids containing gold nanoparticles.

Cavitation in pure liquids and in liquids containing nanoparticles enables applications in mechanics, bio-medicine, and energy. Its evolution carries a significant interest. We describe the multiscale dynamic evolution of ultrafast-laser-induced cavitation in pure and gold-nanoparticles-doped liquids in one-dimensional geometries induced by non-diffractive ultrashort Bessel-Gauss laser beams. Covering the complete electronic and thermomechanical cycle, from the early plasma phase to bubble cavitation and collapse on ms timescales, we reconstitute, using time-resolved imaging with amplitude and phase sensitivity, the hydrodynamic phenomena concurring to bubble evolution. We indicate geometry-specific instabilities accompanying the collapse. The insertion of gold nanoparticles of 200 nm size has subtle effects in the process energetics. Albeit a moderate field enhancement minimizing the contribution to breakdown, the nanoparticles play a role in the overall relaxation dynamics of bubbles. The evolving bubble border in nanoparticles-containing liquids create a snow-plough effect that sweeps the nanoparticles at the gas liquid interface. This indicates that during the macroscopic cavity development, the nanoparticles were removed from the interaction region and dragged by the hydrodynamic movement. We thus shed light on the evolution of cavitation bubbles not triggered but perturbed by the presence of nanoparticles.