  Plasmonic vapour nanobubbles are currently considered for a wide variety of
applications ranging from solar energy harvesting and photoacoustic imaging to
nanoparticle-assisted cancer therapy. Yet, due their small size and unstable
nature, their generation and consequences remain difficult to characterize.
Here, building on a phase-field model, we report on the existence of strong
pressure waves that are emitted when vapor nanobubbles first form around a
laser-heated nanoparticle immersed in water, and subsequently after bubble
rebound. These effects are strongest when the fluid is locally brought high in
its supercritical state, which may be realized with a short laser pulse.
Because of the highly out-of-equilibrium nature of nanobubble generation, the
waves combine a high pressure peak with a fast pressure rising time, and
propagate in water over micron distances, opening the way to induce spatially
and temporally localized damage. Discussing the consequences on biological cell
membranes, we conclude that acoustic-mediated perforation is more efficient
than nanobubble expansion to breach membrane. Our findings should serve as
guide for optimizing the thermoacoustic conversion efficiency of plasmonic
vapor nanobubbles.
