Abstract
We investigated the effect of applying external pressure to ambient water on the size of nanoparticles synthesized by liquid-phase laser ablation. The in-situ diagnostics of the ablation space clearly indicated that the size of nanoparticles was a function of water pressure. On the other hand, we observed no temporal evolution of the size of nanoparticles beyond 0.2 µs after the irradiation of the laser pulse for ablation. These results suggest the importance of parameters in the laser-ablation plasma in the control of the size of nanoparticles.