全固态激光器用光学薄膜的设计制备与性能研究
文献类型：学位论文
| 作者 | 马小凤 |
| 学位类别 | 硕士 |
| 答辩日期 | 2005 |
| 授予单位 | 中国科学院上海光学精密机械研究所 |
| 导师 | 王英剑 |
| 关键词 | 全固态激光器 减反膜 倍频双波长分离膜 半波孔 激光损伤阈值 |
| 其他题名 | Design fabrication and characteristic study of optical coatings for all solid state lasers |
| 中文摘要 | 本文围绕全固态激光器用光学薄膜的特点，主要做了三方面的工作：几种氧化物膜料光学常数的研究；减反膜的制备与性能研究；倍频双波长分离膜的制备与性能研究。本文采用电子束热蒸发和双离子束溅射等技术，制备了7种氧化物膜料的单层膜样品，用光度学方法计算出这几种膜料在400lun到1ZOOIun波段内折射率n的色散关系。实验结果发现ZrO2、HfO2、Ta205、Y2O3和SiO2等膜料的光学常数比较稳定且色散程度比较小；而A12O3膜料在镀制过程中易发生喷溅而导致膜层折射率的厚度非均匀性增大；TiO2膜料在蒸镀过程中易失氧而形成氧空位缺陷。这几种膜料折射率色散关系及各自成膜特性的获得为以后设计、制备和研究相应的光学薄膜元件打下了基础。在矢量设计法的基础上设计出膜系结构规整且光谱性能优良的1064nln单波长减反膜、532m单波长减反膜以及1064nm与532nm双波长减反膜。采用电子束热蒸发技术，制备出这三种减反膜样品。样品的光谱曲线与其理论光谱曲线均有很好的一致性。为研究不同基底、不同基底清洗工艺及内保护层对双波长减反膜激光损伤闭值的影响，分别采用Kg玻璃和石英做基底，从两种基底中分别取部分基底进行超声波清洗，设计出两种膜系结构，采用电子束热蒸发技术制备了薄膜样品。采用波长为IO64nmNd：YAG电光调Q单模激光对薄膜的激光损伤阈值进行测量。结果表明，镀在石英基底上的减反膜其激光损伤阐值较镀在K9玻璃基底上的高；超声波清洗能够提高薄膜的激光损伤闭值；内保护层对减反膜的基底有修复作用。采用对主膜系添加匹配层的方法设计出结构规整、性能优良的lO64nm高透射倍频双波长分离膜，用电子束热蒸发制备样品。样品的实验光谱性能与其理论光谱性能有很好的一致性，完全满足全固态激光器系统所要求的光学性能指标。分别从样品的光谱性能、弱吸收以及激光损伤闽值等方面研究了260℃退火对IO64nm高透射倍频双波长分离膜性能的影响。结果表明，退火后样品的光谱曲线几乎没有发生温漂，说明样品的热稳定性好；而退火使得样品的弱吸收减小；同时其激光损伤闹值提高。分析发现260℃退火能使样品中的ZrO2膜料进步氧化来弥补膜层内的氧空位缺陷，使得膜层内非化学计量比缺陷减少。指出膜料色散、膜层折射率非均匀性以及膜厚控制误差积累等是导致半波孔产生的几个因素，并针对各个因素作了相应的数值计算分析。结果表明膜层厚度周期性误差积累和敏感层厚度误差是导致半波孔产生的主要因素，此外半波孔大小与膜系结构有关。最后从理论上分析了半波孔产生的原因。设计出两种膜系结构，分别采用射频双离子束溅射和电子束热蒸发技术制备出不带半波孔的1064nn高反射倍频双波长分离膜。 |
| 英文摘要 | In this paper, the main topic includes the following aspects: the refractive indices of oxide; AR coating; harmonic beam splitter. Single-layer films of seven kinds of oxides had been fabricated through electron beam evaporation or RF ion beam sputtering technique. The refractive indices and its dispersion from 400nm to 1200nm of these materials are determined with spectrophotometer methods. From the experimental results we concluded the following conclusions. Firstly, the refractive indices of ZrC>2, H1O2, Ta2Os, Y2O3 and S1O2 are stable and their dispersions small. Secondly, AI2O3 material is so prone to sputter during the process of fabrication that its refractive index in-homogeneity of film materials is high. Thirdly, during the process of fabrication TiO2 is easy to loss oxygen so as to form oxygen vacancies. Following the vector method, 1064nm AR coating, 532nm AR coating and a double AR coating were designed respectively. Three kinds of samples were all fabricated through electron beam evaporation, and a good agreement between the theoretical and the tested curves was obtained. In order to study the effects of substrate materials, cleaning technology of substrates and inner protecting layer on laser-induced damage threshold (LIDT) of double AR coatings, we designed two regular film stacks. Samples were deposited on K9 glass and fused quartz substrates by electron beam evaporation, and some substrates were cleaned only by acetone and others by ultrasonic then acetone. Single-shot LIDT was assessed using 1064nm Q-switched Nd:YVC>4 pulsed laser at a pulse length of 12ns. It was found that fused quartz increased LIDT, ultrasonic cleaning increased LIDT, and inner protecting layer can protect the substrate. A harmonic beam splitter al 1064nm with a regular film stack and good optical characteristics was designed by adding matching layers. Coating was deposited by electron beam evaporation. A good agreement between the theoretical and the experimental transmittance was obtained. From three aspects, the above sample annealed in air at 260 °C temperature was studied. It was found that there was almost no shift for the center wavelength after annealing, which showed the sample had a good temperature stability, the absorption of the coating decreased after annealing, and a remarkable increase of LIDT was found. Post-deposition annealing could repair oxygen vacancies in ZrC>2. The dispersion and refractive index in-homogeneity of film materials and error accumulation of layers thickness are all the factors that cause the half-wave hole for a harmonic beam splitter. The numerical calculation and theoretical analysis had been performed. It indicated that among all the factors, the periodic error accumulation and sensitive layer error were the main ones. Furthermore, the stack structure was also related to the half-wave hole. In conclusion, half-wave hole attributed to the admittance mismatching at the half of center wavelength. Two film stacks of harmonic beam splitter were designed, and they were deposited by RF ion beam sputtering technique and electron beam evaporation technique respectively. The half-wave hole was eliminated fundamentally. |
| 语种 | 中文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/16587]  |
| 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 | 马小凤. 全固态激光器用光学薄膜的设计制备与性能研究[D]. 中国科学院上海光学精密机械研究所. 2005. |
入库方式： OAI收割
来源：上海光学精密机械研究所
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