APPJ加工对熔石英元件表面化学重构及其损伤特性影响研究

The surface chemistry reconstruction during APPJ (Atmospheric Pressure Plasma Jet) processing is an imperative scientific problem, which is vital to the performance of fused silica optical components. The proposal focuses on the formation mechanism of surface chemistry reconstruction and its effect on damage characteristics. The physical properties on micro-scale morphology, mechanical properties, adhesion strength and chemical properties on element composition, bond energy, density dynamic changes will be full characterized. The chemical reactions between active atomics, radicals ionized from reaction gas and fused silica surface are to be analyzed to better understand the interface competition behaviors of active atomics etching and radicals reconstruction, thereby revealing the formation mechanism of the chemistry reconstruction. And the effect on transmittance, heat absorption, laser damage threshold of optical components will be investigated, besides the influence of power of radio frequency resource, reactive gas ratio, temperature and flow field on surface chemistry reconstruction will be analyzed. Finally, inhibition strategy of the surface chemistry reconstruction with multi-parameter coupling will be established, providing the theoretical basis for the promotion of fused silica optical element performance.

大气等离子体射流（APPJ, Atmospheric Pressure Plasma Jet）加工过程中出现的表面化学重构层是影响熔石英光学元件性能提高而亟需解决的重要科学问题。课题针对APPJ加工中表面化学重构层的形成机理及其对光学元件损伤特性的影响，全面表征化学重构层的微观结构特征、力学性能、附着强度等物理特性，以及其元素组成、结合键能和键能密度动态变化等化学特性；深入研究反应气体激发电离产生的活性原子和自由基团与元件表面的化学反应过程，理论揭示反应原子刻蚀和自由基团重构的反应竞争机制；探讨表面化学重构作用对光学元件透射率、热吸收和激光损伤阈值等的影响程度，为化学重构层对元件损伤特性的影响评定提供依据；分析等离子体放电功率、反应气体配比以及表面温度、流场等多参数耦合作用下对化学重构作用的影响，并提出抑制表面化学重构过程的多场调控策略，为提升熔石英光学元件性能提供理论基础。

项目针对大气等离子射流加工过程中出现的表面化学重构层及其对元件光学损伤特性影响，通过对化学重构层的物理、化学特性表征，明确了反应气体电离生成的氟碳基团是导致表面化学重构形成的主要原因；通过对大气等离子体激发、反应气体电离及等离子体与工件表面的反应三个阶段分析，并结合发射光谱诊断工艺实验，建立了F原子和CF2基团在刻蚀去除和化学重构反应中的对应关系；通过激光损伤平台测试，研究了表面化学重构对透射率和激光损伤阈值等光学特性的影响；基于COMSOL仿真分析，对等离子体气流场及放电过程建模，计算求解F原子、O原子和活性CFx基团表面的分布形态，为表面化学重构的调控提供有效的理论指导。