Plasmonic microbubbles: nucleation, growth and collapse

Noble metal nanoparticles immersed in a liquid and irradiated by resonant light can rapidly heat up to high temperatures, due to their peculiar absorption ability, and transfer the heat to the surrounding liquid, leading to the formation of bubbles, which have broad application potential in many plasmonic-enhanced processes. For further implementation of these systems, many intriguing challenges should be solved. How exactly do these bubbles form? What is their composition? Which parameters are crucial in bubble dynamics? In this thesis, bubble formation due to the collective effect from nanoparticles immersed in liquid under low-intensity cw-laser irradiation has been extensively studied. All phases of the bubble life cycle have been investigated: from nucleation to growth and subsequent collapse with a broad set of parameters. The bubble growth in water consists of 4 different regimes: first, after some delay time after the beginning of the illumination, a bubble explosively grows and collapses again, typically within 10 microseconds (bubble life phase 1). Right after the collapse of the initial bubble, much smaller unstable oscillating bubbles appear (bubble life phase 2) and maintain continuous cycles typically up to several milliseconds. After bubble stabilization, steady growth takes over. The dynamics of this phase can be divided into two regimes: bubble growth controlled by water evaporation (bubble life phase 3) and a subsequent diffusive growth phase (bubble life phase 4). The influence of the liquid type has also been discussed. Significant differences between plasmonic bubble dynamics in water and organic liquids have been demonstrated. Finally, we investigate the shrinkage dynamics of plasmonic bubbles. A plasmonic bubble during its shrinkage undergoes two different regimes: first, rapid vapor condensation, which dynamics strongly depends on the history of bubble formation, and second, a slow diffusion-controlled bubble dissolution, which is mainly defined by the dissolved gas concentration in the surrounding liquid