  The understanding of the shrinkage dynamics of plasmonic bubbles formed
around metallic nanoparticles immersed in liquid and irradiated by a resonant
light source is crucial for the usage of these bubbles in numerous
applications. In this paper we experimentally show and theoretically explain
that a plasmonic bubble during its shrinkage undergoes two different phases:
first, a rapid partial bubble shrinkage governed by vapor condensation and,
second, a slow diffusion-controlled bubble dissolution. The history of the
bubble formation plays an important role in the shrinkage dynamics during the
first phase, as it determines the gas-vapor ratio in the bubble composition.
Higher laser powers lead to more vaporous bubbles, while longer pulses and
higher dissolved air concentrations lead to more gaseous bubbles. The dynamics
of the second phase barely depends on the history of bubble formation, i.e.
laser power and pulse duration, but strongly on the dissolved air
concentration, which defines the concentration gradient at the bubble
interface. Finally, for the bubble dissolution in the second phase, with
decreasing dissolved air concentration, we observe a gradual transition from a
$R(t) \propto (t_0 - t) ^{1/3}$ scaling law to a $R(t) \propto (t_0 - t)
^{1/2}$ scaling law, where $t_0$ is the lifetime of the bubble and
theoretically explain this transition.
