氟磷酸盐玻璃材料的高能激光辐照发光与激光诱导损伤机理研究

Nowadays, the laser induced damage of optical materials including fused silica et. al. under high energy laser irradiation has been a key limiting factor for the high flux output of laser driven inertial confinement fusion (ICF) systems. Thus, the importance of exploring novel optical materials, which have higher laser-induced damage threshold (LIDT), is becoming increasingly urgent. For the fluorphosphate glass with high LIDT (almost being two times of fused silica) that is explored by our research group, basing on both the fact that the laser-induced damage mechanisms for those widely researched optical materials at present can hardly explain its high LIDT characteristic, and the spontenous volume luminescence as irradiated by high energy pulse laser, as well as the existing relationship that a larger luminescent intensity brings a rather high LIDT, in the project, we take the research on the laser-induced damage mechanism and luminescent physical nature as the main line, take the investigations on the material's structurial response mechanism to high energy pulse laser irradiation and the potential energy transfer mechanism in the materials as the intermediate links, to establish the laser-induced damage model for the fluorophosphate glass in the presence of the luminescence and disclose its laser-induced damage mechanism. Together with the study on the interrelationship between material composition, structure, luminescence and laser-induced damage resistance, new materials with improved LIDT are expected to be obtained through optimizing the glass components and their microstructure tailoring. Therefore, this work,which focuses on disclosing the novel material's high energy laser-induced damage mechanism, will provide theoretical guidance and technical support for developing new glasses with high LIDT, and is of great significance for promoting the development of high energy, high-power laser technology.

在高能激光辐照下，熔石英等光学元件的激光诱导损伤已成为目前限制激光驱动惯性约束核聚变系统高通量输出的主要因素，研究开发具有更高损伤阈值的新材料的重要性日益凸现。本项目针对项目组研究发现的一种高损伤阈值(约为熔石英的2倍)氟磷酸盐玻璃材料，基于现有光学材料激光损伤理论不能解释其高损伤阈值特性，以及高能脉冲激光辐照该材料时伴随出现体发光现象和材料发光强-损伤阈值高的关系；以该材料的激光诱导损伤机理和发光的本质研究为主线，以其对高能脉冲激光的结构响应机制和材料中能量转移机制研究为桥梁，建立发光形式下的材料损伤理论模型，揭示其高能激光诱导损伤机理；研究材料组成-结构-发光-抗激光损伤能力间的关系，以指导通过材料组成优化和结构设计获得更高损伤阈值的材料。本项目揭示新材料的高能激光诱导损伤机理，能够为进一步研究开发新的高损伤阈值材料提供理论指导和技术支持，对促进高能、高功率激光器技术发展具有重要意义。

高损伤阈值、透紫外氟磷酸盐玻璃材料作为新型紫外光学元件在ICF终端光学组件中具有重大的潜在应用。为了揭示其高抗激光损伤的机理，本项目首先通过对系列氟磷酸盐玻璃材料的结构及高能辐照前后微观结构变化、缺陷的产生及转化机制进行研究分析，阐明了材料的材料结构对高能脉冲激光的响应机制。.并且，实验研究了氟磷酸盐玻璃材料在高能激光辐照下的损伤阈值、损伤形貌及其发展规律：对系列氟磷玻璃材料的激光损伤形貌特征、损伤增长趋势进行了离线观察分析。并且，对系列氟磷酸盐玻璃材料的后表面及体损伤的产生与发展过程进行了在线实验研究。研究结论可为延缓材料损伤增长、增加元件使用寿命提供有益的工程指导。.继而，通过对材料激光损伤相关的机械、热学、介电等关键材料性能进行评价，并结合材料的光学、非线性等特性参数的研究和损伤过程研究，以及材料体内发光参数研究，建立了亚稳态下光子吸收和电子跃迁的模型，基本揭示高损伤阈值玻璃材料在高能脉冲激光辐照时辐射发光的物理本质。阐述了材料结构发光等能量转移转化机制对材料损伤阈值的影响，建立了材料体发光条件下，氟磷玻璃材料通过发光释能、减少材料中热沉积造成的热与机械损伤的高损伤阈值理论。.最后，应用高损伤阈值氟磷酸盐玻璃材料的组成、结构、发光与损伤阈值内在关系及辐照诱导缺陷的产生与转化机制，通过组成优化，借助特殊的玻璃熔制制备工艺，对玻璃网络结构进行设计，取得了进一步进展：一方面，透紫外氟磷酸盐玻璃材料的三倍频紫外透过、基频/二倍频吸收等光谱性能可设计、可控制、可实现；另一方面，继续提高了透紫外氟磷酸盐玻璃材料的三倍频紫外激光损伤阈值。进一步验证了透紫外、高损伤阈值氟磷酸盐玻璃材料通过结构发光释能提高损伤阈值的理论，最终获得了从材料组成优化、结构设计出发提高材料抗激光损伤能力的理论和技术方法。.本项目揭示新型紫外光学材料的高能激光诱导损伤机理，能够为进一步研究开发基于氟磷酸盐玻璃的高损伤阈值材料提供理论指导和技术支持，也体现了对促进高能、高功率激光器技术发展的重要意义和应用价值。