Abstract Transient plasmas generated by ns - laser ablation of graphite in air have been investigated by complementary optical diagnosis techniques to study complex multiple structures generated in carbon laser produced plasmas (C-LPP) during the expansion phase. The overall emission was investigated by ICCD fast camera imaging and revealed the structuring of C-LPP into four distinct structures with different evolutions. The dynamic of the C-LPP was analyzed on various expansion directions in order to understand the formation of the main CN dominant structure and of lateral “flaps” with dominant C2 emission. The kinetic and thermal energies of the resulted atoms, ions and molecules were investigated by means of space-and time-resolved optical emission spectroscopy and using the Boltzmann plot and Stark broadening approaches. The effect of the background gas pressure on the formation of molecular carbon structures is discussed and an optimum range of working pressure which maximizes the generation of C2 is found. Based on the acquired data a scenario for the complex carbon structures generation in C-PLL as function of the background gas is proposed.

中文翻译：

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石墨激光烧蚀产生的瞬态等离子体中的多重结构形成和分子动力学

摘要 已经通过互补光学诊断技术研究了空气中石墨的 ns - 激光烧蚀产生的瞬态等离子体，以研究膨胀阶段碳激光产生的等离子体 (C-LPP) 中产生的复杂多重结构。通过 ICCD 快速相机成像研究了整体发射，并揭示了 C-LPP 的结构化为具有不同演变的四种不同结构。分析了 C-LPP 在不同扩展方向上的动态，以了解主要 CN 主导结构和具有主导 C2 排放的横向“襟翼”的形成。通过空间和时间分辨光学发射光谱并使用玻尔兹曼图和斯塔克展宽方法研究所得原子、离子和分子的动能和热能。讨论了背景气压对分子碳结构形成的影响，并找到了使 C2 生成最大化的最佳工作压力范围。基于获得的数据，提出了在 C-PLL 中作为背景气体函数生成复杂碳结构的方案。