Review on experimental and theoretical investigations of the early stage, femtoseconds to microseconds processes during laser ablation in liquid-phase for the synthesis of colloidal nanoparticles

Laser ablation in liquid-phase (LAL) has been developed since the 1990s, but the interest in laser synthesis of colloids has emerged in the last decade due to a significant improvement in the production rate, proven comparative advantages in biomedical and catalysis applications, and recent commercialization. However, the method relies on highly transient phenomena, so that the fundamental understanding lacks behind the LAL synthesis refinement research. The complexity of the physics and chemistry involved has led to experimental and theoretical investigations that attempt to provide a basic description of the underlying processes but face the challenge of temporal and spatial resolution as well as non-equilibrium conditions. It appears that the processes occurring at the early time scales, ranging from femtoseconds to several microseconds are critical in the definition of the final product. The review is mainly dedicated to the comprehensive description of the processes occurring at early time scales, which include the description of laser-matter interaction for ultrashort and short laser pulses, plasma formation processes as well as comparison of the measured plasma parameters at these time scales, and subsequent description of the cavitation bubble dynamics. Furthermore, the plasma and cavitation bubble chemistry are addressed, and their impact on the nanoparticle formation is emphasized.