シリコンナノ粒子の液体中パルスレーザーアブレーション合成における最適なレーザーフルエンス

In this study, we identified the optimal laser fluence range for the synthesis of optically relevant silicon nanoparticles (SiNPs) via femtosecond pulsed laser ablation in liquid (fs-PLAL). We used optimization via minimization to extract total nanoparticle population and concentration from UV-Vis absorption spectrum, and compared them to both single- and multiple-pulse ablation crater volumes. The optimal fluence between 20-30 J/cm² is found to maximize SiNP yield and minimize beam loss caused by persistent bubbles. A systematic analysis of ablation volumes showed that while single-pulsed crater volume increased with fluence, both multi-pulsed ablation volumes and measurable SiNP volumes peak near 25 J/cm² before decreasing. This drop is due to the formation of persistent cavitation bubbles that scatter incoming pulses and reduce ablation efficiency. The peak nanoparticle synthesis yield was ∼ 0.311 μg/min, which is comparable to the literature values. Importantly, this yield value is expected to be further improved by using high-speed scanning systems (e.g., galvo mirrors) to reduce pulse overlap and avoid cavitation bubble interference. These findings offer practical guidance for tuning PLAL parameters in future high-throughput, optically tuned SiNP production.