Femtosecond laser-produced plasma driven nanoparticle formation in gold aqueous solution

We report an experimental study of laser-induced plasma in a gold aqueous solution (H[AuCl4]) and we explore the correlation between plasma properties and rate of the synthesis of gold nanoparticles (Au NPs). The concentration of photo-excited carriers produced by a Ti-sapphire laser (wavelength 800 nm, pulse duration 120 fs) was probed in a extremely wide range of laser energies (∼0.2–200μJ) using a pump–probe and scattering microscopy techniques. The experimental data that we obtained enabled us (i) to identify the multiphoton and avalanche regimes of the ionization process in liquid water and (ii) to link the mechanisms of laser ionization with the possibility of NPs synthesis.