Overlapping of Laser Pulses and its Effect on the Yield of Silver Nanoparticles in Water

Laser pulse overlapping is one of the least studied parameters involved in the production of nanoparticles by laser ablation confined in liquids. In order to explore its effect on the yield of nanoparticles, we employed a motorized XY translation stage with speed control, which allowed us to regulate the overlapping of laser pulses on the target. Four different XY speed settings were used in the laser ablation of a silver target in distilled water; each process in a virgin surface, using the 532 nm emission of a Nd：YAG laser, with fixed spot diameter of 1 mm and pulse energy of 0.5 J/pulse. Peak optical absorption, in UV-Visible measurements of each nanoparticle suspension, decreases as the employed pulse overlapping increases. According to the well known Beer-Lambert relation, this implies that nanoparticle yield decreases as the pulse overlapping increases.