激光陶瓷镀膜元件激光损伤特性和力学特性研究
文献类型：学位论文
| 作者 | 郭佳露 |
| 学位类别 | 硕士 |
| 答辩日期 | 2016 |
| 授予单位 | 中国科学院上海光学精密机械研究所 |
| 导师 | 赵元安 |
| 关键词 | 激光陶瓷 激光损伤 损伤机制 薄膜 膜基结合 |
| 其他题名 | The study on the Laser-induced damage and Mechanical Properties of the films coated on Laser ceramic |
| 中文摘要 | 作为现代材料领域发展迅速的激光陶瓷，具有陶瓷材料的特性，且在制备成本、尺寸（与单晶相比）、热力学性能（与玻璃相比）方面具有明显优势，是最有发展前景的激光增益介质之一。目前美国已成功研制出输出功率超过100KW的陶瓷激光器，日本计划利用Yb:YAG陶瓷搭建千焦耳100Hz的高能重频激光系统。作为增益介质的激光陶瓷不可避免需要镀制各类激光薄膜，而镀膜元件应用于高功率、高能量的激光系统中，对薄膜的抗激光损伤性能和力学性能提出了一定的要求。为此本文针对激光陶瓷镀膜元件的激光损伤特性和力学特性进行了探索研究，主要从以下几个方面开展研究工作： 研究了Nd:YAG和Nd:LuAG激光陶瓷的损伤特性。实验结果表明激光陶瓷的体损伤阈值低于表面损伤阈值，透过率越高的样品的体损伤阈值越高。Nd:YAG激光陶瓷的损伤主要由结构性的气孔缺陷诱导产生，气孔抛光后在陶瓷表面呈凹坑状，对激光表现出散射作用；气孔在体内呈规则圆形，对激光表现出干涉增强作用，这导致Nd:YAG陶瓷的体损伤阈值低于表面损伤阈值。Nd:LuAG陶瓷表面的初始损伤主要由吸收性杂质诱导产生，其在~3J/cm2能量密度辐照下即出现由晶界导致的力学破坏。 对镀制在LuAG激光陶瓷上的单层HfO2薄膜的损伤特性进行了研究。结果发现镀膜后薄膜的表面损伤阈值相较于陶瓷的体损伤和表面损伤阈值有所提高。这主要归结于两个方面：一方面，镀膜前离子源技术对陶瓷基底的清洗降低了陶瓷表面的缺陷密度；另一方面，膜基间作用力使得薄膜一定程度上对基底起到了保护作用。 对单晶晶体和多晶陶瓷上HfO2薄膜的微观结构和力学特性进行了对比研究。结果表明二者均为软膜硬基体系，基底的晶态结构影响着其上薄膜的微观结构和力学特性。HfO2薄膜呈多晶态结构，单晶晶体与薄膜晶态差异较大，结合力较差，为3.99mN；多晶陶瓷与薄膜晶态差异较小，结合力较好，为7.74mN。 |
| 英文摘要 | Laser ceramic is rapidly developed in modern material field. Not only it has the characteristics of ceramic material, it also has outstanding preparation advantage compared to crystal, and excellent thermo-mechanical properties compared to glass. So the laser ceramics has become a very promising laser gain medium. So far the America has built ceramic laser with output power of over 100KW, and the Japan is planning to build a high-energy laser system with a 100Hz repetition rate and power-scaling up to 1KJ. As the gain medium, it inevitably require to be coated with different kinds of laser films. The coated ceramic is used in high-power and high-energy laser system, it’s required to has good resistance of laser damage and mechanical properties. In this dissertation, researches have been carried out on the following aspects: The damage characteristics of Nd:YAG and Nd:LuAG laser ceramic were investigated. It is clarified that for the laser ceramic the bulk laser-induced damage threshold (LIDT) is lower than the surface LIDT, and the ceramic with a higher transmittance has a higher bulk LIDT. The surface damage of Nd:YAG is mostly induced by pore. As the pore in surface will cause the scattering of the light, and the pore in bulk will cause a light field enhancement, so the bulk laser-induced damage threshold (LIDT) is lower than the surface LIDT. In low fluence, the surface damage of Nd:LuAG is mostly induced by absorptive impurity. In about 3J/cm2 fluence, the surface damage of Nd:LuAG is mostly induced by grain boundary. The damage characteristics of HfO2 films coated on ceramic were investigated. The films coated on the ceramic have a higher surface LIDT than the ceramic. There are two possible reasons: On the one hand, the ion-assisted deposition process cleand the substrates which makes the film’s defect density fewer. On the other hand, the adhesion force between the films and the substrate makes the films suppress the defect on the surface, which make the defect harder to induce the damage. By comparing the microstructure and mechanical properties of HfO2 films coated on ceramic and crystal, we found the crystalline structure of the substrate affects the microstructure of the films significantly, and the crystalline orientations of the HfO2 films on both substrates are polycrystalline. The crystalline state difference between the crystal and the films leads to a worse adhesion force, which is 3.99mN. And the adehesive force between the films and ceramic is 7.74mN. |
| 语种 | 中文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/17011]  |
| 专题 | 上海光学精密机械研究所_学位论文 |
| 推荐引用方式 GB/T 7714 | 郭佳露. 激光陶瓷镀膜元件激光损伤特性和力学特性研究[D]. 中国科学院上海光学精密机械研究所. 2016. |
入库方式： OAI收割
来源：上海光学精密机械研究所
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