Optimization of laser plasma for in situ underwater surface elemental analysis

对于通过脉冲激光照射水中固体表面所产生的等离子体的发射光谱法对浸没在水中的固体材料进行原位元素分析，难以获得稳定且明确的原子发射谱线。本文着重研究了辐照激光的时间分布对等离子体和空泡行为的影响，并试图通过优化辐照条件和发射光谱检测技术来获得更清晰的原子发射谱线。此外，我们试图从等离子体形成机制的角度来澄清为什么这样的条件给出清晰的原子发射线的原因。

For in situ elemental analysis of solid materials submerged in water by the emission spectroscopy of the plasma generated by the pulsed laser irradiation of the solid surface in water, it is difficult to obtain stably well-defined atomic emission lines. In the present study we focused on the effects of the temporal profile of the irradiation laser upon the behavior of the plasma and the cavitation bubble, and tried to obtain clearer atomic emission lines by optimizing the irradiation conditions as well as the detection techniques for the emission spectra. Also, we tried to clarify the reason why such conditions give clear atomic emission lines from the point of view of the plasma formation mechanism.