We form sub-micrometer-sized vapor bubbles around a single laser heating gold
nanoparticle in a liquid and monitor them through optical scattering of a probe
laser. The fast, inertia-governed expansion is followed by a slower contraction
and disappearance after some tens of nanoseconds. In a narrow range of
illumination powers, bubble time traces show a clear echo signature. We
attribute it to sound waves released upon the initial explosion and reflected
by flat interfaces, hundreds of microns away from the particle. Echoes can
trigger new explosions. A steady state of nanobubble with a vapor shell
surrounding the heated nanoparticle can be reached by a proper time profile of
the heating intensity. Stable nanobubbles could have original applications for
light modulation and for enhanced optical-acoustic coupling in photoacoustic
microscopy