Bubble Generation in Fluid Containing Gold Nanoparticles by Laser Irradiation. (2) Evaporation with a long temporal delay*

A nanosecond pulse laser irradiated gold nanoparticles in the water, causing plasmonic bubbles around the nanoparticles. According to the simple numerical simulation, the water temperature surrounding the nanoparticles increases over boiling in several nanoseconds. The superheating water generates rapid bubble generation, with some external events, such as pressure pulse. The high-speed camera (360~900kfps) resolved the bubble generation and collapsed with a microsecond scale. We observed the bubble generation at the wall just after the laser irradiation. The gold nanoparticle stacked on the wall may generate a giant wall bubble. Then, at 50 microseconds after the laser irradiation, tiny bubbles were generated in the middle of the cell. This means the superheating water surrounding the nanoparticles remains stable for over 50 microseconds, following boiling and condensation in 10 microseconds. Superheating stabilization will be the key to such a long temporal delay phenomenon.