冲击压缩下蓝宝石窗口的光折射率和结构相变的实验与理论计算研究

In this project, the optical refractive index and phase transition of sapphire under shock pressure range from 65 to 200 GPa will be investigated by using a two-stage light gas gun in accord with a time-resolved in-situ diagnostic technique and theoretical calculation. A quantitative description of optical refractive index as a function of the shock state will be carefully determined. It will be paid more efforts to explore the influence of shock-induced phase transition, defects on the refractive index behavior, and clarify the controversy of the shock-induced phase transition and understand its physical mechanism. This project not only puts forward a method which combines the refractive index measurement with theoretical calculation analysis to study the shock-induced phase transition, but also gives the velocity correction factors for sapphire window shocked above 65 GPa, and provides some insights on the underlying mechanism of the optical refractive index, phase transition and optical transparency of shocked sapphire window.

本项目拟以二级轻气炮为冲击加载手段，结合原位实时诊断技术及理论计算分析，研究65-200 GPa冲击压力范围内蓝宝石的光折射率及结构相变，获得精确的光折射率随冲击密度变化的定量关系，揭示冲击诱导的结构相变、点缺陷等因素对光折射率的影响规律，并澄清冲击相变争议，认识其相变机理。本项目不仅提出一种通过开展冲击压缩下光折射率测量与计算分析相结合，研究材料冲击相变的新方法，研究成果还为冲击压力高于65 GPa时使用蓝宝石窗口提供粒子速度修正因子，并有助于认识蓝宝石在高压下的光折射率和相变规律，最终为理解蓝宝石窗口的冲击光学透明性下降机理提供物理指导。

蓝宝石作为冲击波物理实验中重要的窗口材料，深入认识其在冲击压缩下的光学和力学性质，对正确解读实验信号至关重要。此外，蓝宝石还是下地幔的主要成分，深入探索其在高压下光折射率变化和结构相变机制也具有重要的科学意义。本项目以二级轻气炮为冲击加载手段，结合原位实时诊断技术及理论计算分析，研究了25-200 GPa冲击压力范围内蓝宝石的光折射率及结构相变，获得了精确的光折射率随冲击密度变化的定量关系，揭示了冲击诱导的结构相变、点缺陷等因素对光折射率及光学透明性的影响规律。研究成果不仅澄清了蓝宝石的冲击相变争议，还建立了相变、点缺陷等因素与光学性质间关联，对理解其高压物性及在冲击波物理实验中的应用具有指导意义。