超低损耗激光薄膜电子辐照损伤动力学与控制方法研究

The ultra-low loss films mirror is core element for the ring laser gyroscope (RLG). The performance degradation of the ultra-low loss films worked in the discharge area have been a bottleneck problem. It has limited the development of the RLG technology with high precision and long endurance in China. Moreover, it may affect the safety and reliability of the aircraft which equipped the RLG for inertial guidance. The charged particles irradiation effect in the thin films was studied and most of which was the high energy particle more than keV. It is a research focus in the area of the film optics at present. The RLG cavity is a discharge environment with low pressure plasma. So, the project will start from the interaction between the low energy electron (<100eV) and thin film and study on the physical mechanism of the performance degradation of the ultra-low loss films. Three key scientific missions will be completed during the study. The first is the physical model and the calculation method of the relationship between the time-dependent electron radiation and the films optical properties; The second is the theoretical calculation and characterization of the thin films thickness of the damage layer caused by the low energy electron irradiation; The last is the design of the ultra-low loss films with the control of the thin films energy band. The problem of the ultra-low loss films performance degradation will be solve. This project will promote the development of the study on the charged particles irradiation effect in the thin films from high energy (>keV) to low energy (<100eV). The bottleneck problem in the development of the RLG technology with high precision and long endurance will be solved. And the completion of the project will lay a foundation for the safety and reliability of the aircraft which equipped the RLG for inertial guidance. The scientific significance and the application value are obvious.

超低损耗薄膜反射镜是激光陀螺的核心元件，工作在放电区的超低损耗薄膜性能退化成为我国高精度、长航时激光陀螺技术发展的瓶颈问题，影响到装备激光陀螺惯导的飞行器安全可靠性。光学薄膜的带电粒子辐照效应研究主要集中在keV以上的高能粒子辐照效应，是目前薄膜光学领域研究的热点。激光陀螺谐振腔为低压等离子放电环境，因此从低能(<百eV)电子与薄膜相互作用为出发点，探索超低损耗薄膜性能退化的物理机制，突破含时的电子辐照与薄膜光学性能之间的物理模型和计算方法、低能电子辐照薄膜损伤层厚度的理论计算与测试表征问题、以及超低损耗薄膜设计和薄膜能带结构控制三个关键科学问题，解决超低损耗薄膜性能退化问题。本项目推进了光学薄膜带电粒子辐照效应研究从高能(>keV)向低能(<百eV)方向发展，解决我国高精度、长航时激光陀螺技术发展瓶颈问题，为我国激光陀螺惯性导航飞行器的安全可靠性奠定基础，具有显著的科学意义和应用价值。

随着激光器技术和光电探测技术的快速发展，超高精度激光测量装置逐渐成为激光技术重要应用领域之一。以激光惯导为代表的前沿激光测量技术提出了对高性能超低损耗激光薄膜元件迫切的需求，其长期工作可靠性强烈依赖于超低损耗薄膜元件的总损耗稳定性。该项目针对超低薄膜激光薄膜在放电等离子环境下性能退化问题开展了理论和实验研究工作，完成了以下研究：（1）对L型谐振腔放电等离子环境中电子分布和电子能量分布进行了仿真计算，实现了放电等离子环境的表征，并对低能电子辐照薄膜损伤层深度进行了理论计算，建立了基于He-Ne放电光谱的电子温度和浓度的测量装置；（2）采用RFV模型表征了电子辐照感应电导率延迟效应，改进了基于能带结构的光学薄膜介电常数计算物理模型，建立了激光陀螺环境的薄膜损伤在线测量装置，实现了电子辐照下光学薄膜介电常数含时响应的表征；（3）提出了抗电子辐照增强的膜系结构优化设计方法，建立了离子束溅射工艺参数与Al2O3薄膜性能关联性，获得了基于能带调控的高稳定性离子束溅射超低损耗薄膜保护膜制备方法；（4）开展了超低损耗反射镜元件等离子放电环境下光强衰减实验，实验结果表明连续工作23天后光强衰减率为9.4%，达到了预期研究效果。该项目的研究提高了超低损耗薄膜等离子放电环境下工作稳定性，为我国激光陀螺惯性导航飞行器的安全可靠性奠定了技术基础，具有重要的科学意义和应用价值。