| 题名 | 高功率激光器用溶胶－凝胶增透膜相关研究 |
| 作者 | 贾巧英 |
| 学位类别 | 博士 |
| 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 | 姜中宏 |
| 关键词 | 溶胶-凝胶 增透膜 强激光负载 改性 悬胶体 |
| 其他题名 | Research related to sol-gel derived antireflective (AR) coatings for high-power lasers |
| 中文摘要 | 与物理气相沉积薄膜相比，溶胶一凝胶光学薄膜在抗激光破坏和大面积涂膜等方面具有明显优势，在惯性约束核聚变实验装置（激光核聚变）中得到较好应用。本论文主要围绕"神光"系列高功率固体激光器的主放大器隔板玻璃表面增透膜、超短脉冲高功率钦宝石激光器的钦宝石晶体表面增透膜以及激光核聚变中广泛使用的多孔5102增透膜的稳定性与改性等内容展开研究。论文第一章综述了溶胶一凝胶技术原理与应用，对该技术制备薄膜过程的各个环节和特点作了详细介绍，概述了溶胶一凝胶薄膜在激光聚变装置中的使用状况，重点介绍了增透膜与磷酸二氢钾晶体表面防潮增透膜的研究进展。此外，根据论文研究背景，简单介绍了悬胶体涂膜液的制备。论文第二章主要研究了隔板玻璃表面宽光谱增透膜的制备。结果发现，通过配方优化可以制备性能稳定、成膜质量良好的TiO2薄膜；随着单次涂膜厚度和热处理过程中升温速度的增加，TiO2薄膜的开裂程度变大，在适当温、湿度条件下对薄膜进行预处理可有效抑制TiO2薄膜的开裂。通过不同溶胶间复合制备了可用于隔板玻璃表面增透的双层、三层宽光谱增透膜，使隔板玻璃的透过率在主放大器钱玻璃主吸收峰波段处的平均提高6％以仁。"神光II"第九路主放大器在线试验结果表明，隔板玻璃表面涂制由1．90／1．44折射率薄膜组成的双层增透膜使主放大器的增益提高5％以上，经高能氛灯的上百次放电辐照，薄膜表面没有出现明显的破坏迹象，透过率基本保持不变，达到了预期目的。论文第三章重点研究了水热合成原理制备TiO2悬胶体过程中制备条件对胶溶反应和胶溶颗粒粒度的影响。结果表明，沉淀要完全胶溶，r（［H2O／[Ti]）必须大于某一数值，本实验中r大于5。；介质的pH值眼四交溶刊）对胶溶反应至关重要，TiO2沉淀只有在强酸或强碱作用卜刁能完全胶溶，在酸性环境中，胶溶反应速度随胶溶剂浓度的增加而增人，［H+]［Ti］0.9时，胶溶悬胶体的稳定性较差；温度对胶溶反应速度影响较大，在20一80℃范围内，胶溶反应速度随温度升高首先加快，50℃左右达到最大值，随后随温度的进一步升高稍有一下降；醇、聚乙二醇和聚乙烯毗咯烷酮（PVP）不利于胶溶反应进行，但有利于涂膜液成膜胜能改善，月义溶反应速度随醇分子中烃基链的增大和异构化而变慢；陈化有利于TiO2，旨胶体中颗粒粒度的均一化，随[H+]J／[Ti]的增加，TiO2粒径呈先降后增趋势，其最小值对应的[H＋]／[Ti]与r密切相关；含醇TiO2悬胶体中颗粒粒度和粒度分散性随烃基链的增大与异构化而增大，聚乙二醇和PVP有利丁'胶粒粒径的均匀化；HNO3和胺碱胶溶得到TiO2悬胶体中颗粒主要为多晶锐钛矿。第四章主要针对钛宝石表面强激光负载增透膜进行相关研究。结果表明，用(Hr3S15掺杂S102悬胶体制备得到的51O2改性薄膜具有较强的抗激光负载能力，在激光波民800nm、脉宽300ps时的激光破坏闽值不低于2．2）／cm2，且能大幅度降低认宝石表而反射，使饮宝石在激光输出波段（7750-850nm1）的平均透过I率从涂膜前的85．6％提高到99％左右，激光输出峰值功率处的透过率和反射率分别为99．10％和0．38％，在超短脉冲强激光领域具有潜在的应用价值。在第四章第三节中，重点研究了CH3SIO15对5102改性悬胶体与相应薄膜性能的影响。结果发现，改性悬胶体粘度受CH3SiO1.5的影响较大，稳定性所受影响较小，改性溶胶的使用寿命超过两个月；改性薄膜的折射率随其中CH3siol．5含量的增加而增大，当CH3SiO1.5的体积含量超过50％时，改性薄膜的折射率趋于稳定，同时改性薄膜的表面形貌也发生了明显变化；热处理温度超过150℃时，薄膜的稳定性能大幅度提高，其透过率在室温放置半年后基本保持不变。第五章主要讨论了多孔S1O2薄膜的潮解破坏，并进行了相应的改性研究。结果表明，环境温、湿度增大明显加速了多孔S1I2薄膜的潮解破坏过程，其破坏主要是由吸附在薄膜孔隙中的水气分子引起，从点破坏开始、逐渐扩大形成分枝、分枝发展形成网络遍布整个薄膜；CH3SiO1.5、二甲基二乙氧基硅烷（DMDES）与六甲基二硅氮烷（HMDS）可有效提高薄膜的耐环境稳定性，当改性剂含量相差不大时，改性薄膜的潮解破坏程度，HMDS改性薄膜的最小，CH3SiO1.5与DMDES改性薄膜的稍大些；改性薄膜的机械性能，HMDS的改善效果明显不如CH3SiO1.5与DMDES的效果好；用三氟丙基二氯硅烷（TFPMDCS）改性51O2薄膜，在改性薄膜中引入甲基的同时也引入三氟丙基，改性薄膜对水的接触角变化较小，其环境稳定性和机械性能明显提高：在SiO2悬胶体制备过程中掺入PVP，有利于薄膜机械性能的提高，改性薄膜具有良好的增透效果和较强的抗激光损伤性能，在多孔SiO2薄膜改性中具有潜在的应用前景。最后是本论文的结论，概括了全文的主要研究结果和创新点。 |
| 英文摘要 | In recent years, sol-gel derived optical coatings were widely used in Inertial Confinement Fusion (ICF) system due to their superior properties such as high laser resistance and easy to deposit large area coatings compared with conventional physical vapor deposition (PVD) ones. In this article, AR coatings for amplifier blastshields in "Shenguang" high-power solid lasers and Ti-sapphire in ultrashort pulse high-power lasers were prepared, and humidified damage mechanism and modification of porous silica coatings were investigated. In chapter one, the basic principle and applications of sol-gel technique were reviewed, as well as sol-gel derived coatings. Research progress of sol-gel derived coatings in ICF system was summarized in detail, especially AR and protective ones for KDP crystal. In addition, based on the research background, preparation of different colloidal suspensions was also introduced. In chapter two, emphases were placed on broadband AR coatings for amplifier blastshields. Results showed that stable and excellent performance titania coatings can be obtained by optimizing molar ratio of raw materials. It was also observed that the extent to cleavage of titania coatings deposited became more serious with the increase of thickness of coatings-deposited once and the rate of rising temperature, which could be improved after being exposure to the relative humidity of 95% at about 50 °C for hours. Two- or three-layer broadband AR coatings, which could enhance the blastshields transmission over 6% in the range of absorption bands of laser glass, were both-sided coated from the different composite sols in dip-coating methods on amplifier blastshields. The results in "Sheng-Guang II" ninth pass testing online showed that amplifier gain was more than 5% when two-layer AR coatings composed of 1.90/1.44 index pairs were deposited on both-sided blastshields, which remained the same after flashlamp glow-discharges test. The effects of process parameters were mainly studied on the peptization reaction and peptized particle sizes in the preparation of titania colloidal suspensions from alkoxides by means of hydrothermal synthesis in chapter three. It was estimated that complete peptized titania suspension could be obtained only if when r value (that is the ratio of water to titanium) was large enough, which was more than 50 in our experiments, and that titania precipitate could be peptized fully in strong acid and alkali. Peptization reaction rate, sensitive to the peptization temperature, enhanced with [it] concentration increase when the molar ratio of [H^/fTi] was in the range from 0.1 to 0.9 in acid-peptized state. The organics, such as alcohols, polyethylene glycol and polyvinylpyrrolidone (PVP), hindered the peptization reaction but could be in favor of coatings-formed performance. With the molecular weight increase and isomerization of acohol (with exception of butanol), the peptization rate decreased, and the peptized particle sizes and size distribution became larger. The peptized titania exhibited polycrystal anatase phase both under HNO3- and tetramethylammonium hydroxide-peptized conditions. In chapter four, AR coatings with high laser resistance were discussed for Ti-sapphire used mainly in ultrashort pulse high-power lasers. Results indicated that the modified silica AR coatings, formed on Ti-sapphire crystal from the modified silica colloidal suspension with CH3SiOi 5 prepolymer, demonstrated laser damage thresholds more than 2.2 J/cm2 at 800nm with the pulse of 300 picosecond (ps), meeting the experimental requirements, and enhanced the transmission rate from uncoated 85.6% to over 99% after coated within the range of laser output waveband. The reflectivity and transmission of coated Ti-sapphire at output power peak of ultrashort pulse high-power lasers were 0.38% and 99.10% respectively. The influence of CH3Si0i5 prepolymer on the properties of modified silica suspension and derived coatings were stressed in the third section. It was discovered that the viscosity of modified silica suspension changed apparently with CH3Si0i.5 content increase, and the modified silica suspensions were demonstrated relatively stable for two months at room temperature. The refractive index of modified coatings increased with CH3Si0i5 prepolymer increase, and tended to be unchanged with CH3SiOi 5 prepolymer over 50% in volume, at the same time the morphology changed greatly. The stability of coatings deposited improved in some degree after heat treatment above 150°C. The humidity induced damage of standard porous silica coatings deposited on BK7 glass substrates, as well as some modifications, was discussed in chapter five,. It was demonstrated that humidity increasing, or temperature rising, could speed up the humidity induced damage of porous silica coatings, which might be caused by the water vapor molecule adsorbed in the porosity. Humidity induced damage began with points, which slowly enlarged to form ramification, and ramification further developed into damages network throughout the coatings. The humidity stability resistance of coatings could be enhanced when they were modified with CH3S1O15 prepolymer, dimethyldiethoxysilane (DMDES) or hexamethyldisilazane (HMDS), in which humidity stability resistance of HMDS-modified coatings was better than that of CH3SiOi sand DMDES modified ones at the same content in modified coatings. As for the mechanical properties, the coatings modified with CH3SiOi 5 and DMDES would be better than that of HMDS-modified. Although the contact angles for water of coatings modified with trifluoropropylmethyldichlorosilane (TFPMDCS) were relatively small, both the humidity induced resistance and mechanical property were enhanced distinctly. Mechanical property of modified coatings, which having excellent AR effect and high laser damage resistance, could also be enhanced when PVP was introduced into silica suspension during the preparation stage, which made them particularly suitable for modification of porous silica coatings. At the end of this dissertation, main findings of the present work are outlined, and the innovative points are presented. |
| 语种 | 中文 |
| 内容类型 | 学位论文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/15405]  |
| 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 | 贾巧英. 高功率激光器用溶胶－凝胶增透膜相关研究[D]. 中国科学院上海光学精密机械研究所. 2005. |
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