真空环境下光学薄膜抗激光损伤降级机理研究

With the development of space technology, laser technology has been widely used in vacuum. Optical thin film, as a pivotal component, the laser-induced damage threshold is greatly reduced and the service life is shortened in vacuum environment, which has become an important bottleneck to restrict the application of laser technology in vacuum or space. Aiming at the serious degradation of optical thin film in vacuum environments, the study purpose in this project is to reveal the serious degradation mechanisms of laser-induced damage resistance for optical coating. Based on the laser-induced damage behaviors and characteristics of optical coatings in vacuum environments, and as the prerequisite of the change of photo-thermal characteristics, structural properties of optical film in vacuum environments, the present work will be devoted to analyzing the laser coupled thermal-mechanical damage process, defect induced damage process, ionization and damage process of the optical film induced by plasma due to laser irradiation, as well as the inter-coupling process of defects and organic contamination in vacuum environments. By this investigation, the degradation mechanism of the interaction between laser and optical films in vacuum environments will be established. At the same time, a theoretical model for the laser-induced damage of optical films induced by organic contamination will also be presented. On that basis, for enhancement of laser damage resistance ability and service life of optical thin film in vacuum environment, the improvement techniques of the laser-induced damage resistance of optical films will be explored.

空间技术的发展使激光技术在真空领域得到了广泛应用，光学薄膜作为激光系统中关键部件，在真空环境中损伤阈值极大降低、使用寿命严重缩短，已经成为限制激光技术在真空或空间领域应用的重要瓶颈。本项目将针对光学薄膜在真空环境中抗激光损伤严重降级问题，揭示其降级的机理。项目将以真空系统中光学薄膜元件激光损伤行为及特性为基础，以真空环境中光学薄膜光热特性和结构特性的变化为前提，深入分析真空环境中光学薄膜在激光辐照下光、热、力耦合损伤过程、缺陷诱导损伤过程、激光辐照诱导等离子体对材料离化和损伤过程以及有机污染与薄膜中缺陷的相互耦合过程，建立真空环境下光学薄膜抗激光损伤降级的本征机理以及有机污染诱导光学薄膜抗激光损伤降级的机理模型，探索改善真空环境中光学薄膜元件抗激光损伤降级的技术途径，提升光学薄膜在真空环境中抗激光损伤能力和使用寿命。

空间技术的发展使激光技术在真空领域得到了广泛应用，光学薄膜作为激光系统中关键部件，在真空环境中损伤阈值极大降低、使用寿命严重缩短，已经成为限制激光技术在真空或空间领域应用的重要瓶颈。本项目详细研究了真空环境中激光辐照下缺陷诱导的光、热、力、等离子体耦合损伤及激光辐照诱导等离子体对薄膜材料的离化、改性过程，揭示了真空环境中光学薄膜抗激光损伤降级的本征机理；其次从缺陷与有机污染之间光场及温度场的耦合分析揭示了密闭真空环境中放气有机污染诱导光学薄膜元件抗激光损伤降级的机理，提出了真空激光系统中尽可能抑制光学薄膜表面缺陷及采用高折射率的封装材料，降低缺陷与有机污染的耦合效应。在此基础上，提出了适当的水蒸气气氛保护技术对真空环境下光学薄膜损伤阈值提高改善技术；揭示了热退火技术对真空环境下光学薄膜的抗损伤能力改善的机制；提出了基于热反射测量实时监控激光预处理效应的方法，发展了真空环境中改善光学薄膜抗损伤降级的激光后处理技术。这些科学问题的解决提升了对真空环境下光学薄膜损伤机制的理解，为真空环境下高损伤阈值强光薄膜的制备提供了理论指导和技术支撑，将会促进高能、高功率激光技术在真空和空间领域的发展。在项目执行期间，共发表标注项目资助的高水平学术论文12篇，申请国家发明专利3项，出版学术专著一项。开展了广泛的课题组之间的交流与合作，完成了本项目的既定目标。