Diagnostics of nanoparticle formation process by laser ablation in a background gas

摘要

We have developed a new visualization technique named as re-decomposition laser-induced fluorescence (ReD-LIF), in order to investigate the dynamics of clusters, which are difficult to be visualized by any other means. In the ReD-LIF technique, clusters or nano-particles synthesized in the laser ablation plume are decomposed by laser irradiation and the atoms generated by the decomposition are visualized by LIF. This technique is very sensitive than the other visualization technique, because we can use the sensitive LIF technique. Decomposition of nano-particles by the laser irradiation is considered theoretically and the characteristics of ReD-LIF technique are compared with other visualization techniques such as laser-induced fluorescence (LIF) and Rayleigh scattering. The ReD-LIF technique has been applied for the visualization of the Si nano-particle synthesis process. Based on the results, the particle dynamics in the ablation plume generated in the background gas during Si nano-particle synthesis are described besides the basic characteristics of the ReD-LIF signal.