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Development of High Quality and High Laser-Resistive Multilayr Dielectric Thin Films by Means of Chemical Surface Reaction

利用化学表面反应开发高质量高抗激光多层介质薄膜

基本信息

批准号：
07558286
负责人：
YAMANAKA Tatsuhiko
金额：
$ 1.41万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1997
项目状态：
已结题

项目摘要

It is very expensive to make meter size multilayr optical films with high uniformity and high laser damage threshold by an evaporation method. In order to develop a cost-effective method, we have studied a chemical surface reaction technique applied an atomic layr epitaxy method. In the chemical surface reaction, the films can be easily deposited by introducing a reactant and an oxidizer alternatively, and the thickness can be precisely controlled only by the number of reactive cycles with a reaction chamber of which size is as large as substrate size. Aluminium oxide (Al_2O_3) films were grown using trimethylaluminium (TMA) as a reactant gas and hydrogen peroxide (H_2O_2) as an oxidizer for a low refractive index layr. Titanium dioxide (TiO_2) films were grown using tetrachlorotitanium (TiCl_4) and hydrogen oxide (H_2O) for a high refractive index layr.The deposited film on glass plates showed very uniform distribution of thickness within 1% over 250-mm region which limited by a chamb … More er size. The results mean that this method is effective to grow the films with high uniformity and precise thickness for large optics. The refractive indices depended strongly upon the substrate temperature, and the growth rate depended upon the exhaust performance of the residual gas and upon the introduced pressure of oxidizers. The properties of films were not serious effected by other deposition parameters. These results suggest that this method can grow films by a stable and reproducible manor without any sensitive controls. Anti-reflective coatings consisting of Al_2O_3 and TiO_2 Layrs were deposited, and the optical characteristics were measured. The tested anti-reflective coatings are for 532-nm and 1064-nm light. Residual reflectivity of lower than 0.1% was easily obtained and was agreed well with the design value. The laser-induced damage threshold of Al_2O_3 and TiO_2 fulms was 7 J/cm^2 and 3.5 J/cm^2 at 1-ns, 1064-nm laser pulse, respectively. These films are applicable to lasers although some improvements are required for high power lasers such for laser fusion.In conclusion, the developed chemical surface reaction method showed an excellent controllability in thickness and uniformity and was applicable for any large optical apparatus. It is expected to improve laser damage threshold for high power lasers. Less

采用蒸发法制备高均匀性、高激光损伤阈值的米级多层光学薄膜是非常昂贵的。为了开发一种经济有效的方法，我们研究了一种应用原子层外延法的化学表面反应技术。在化学表面反应中，通过交替引入反应物和氧化剂，可以很容易地沉积薄膜，并且在与衬底尺寸一样大的反应室中，仅通过反应循环次数就可以精确控制薄膜的厚度。以三甲基铝（TMA）为反应物，过氧化氢（H_2O_2）为氧化剂，制备了低折射率层氧化铝（Al_2O_3）薄膜。采用四氯钛（TiCl_4）和氧化氢（H_2O）制备高折射率层二氧化钛（TiO_2）薄膜。在250-mm范围内，受腔室尺寸的限制，沉积膜的厚度分布非常均匀，在1%以内。结果表明，该方法可以有效地生长出具有高均匀性和精确厚度的大型光学薄膜。折射率在很大程度上取决于衬底温度，生长速率取决于残余气体的排气性能和氧化剂的引入压力。其他沉积参数对膜的性能影响不大。结果表明，该方法可以在不受任何敏感控制的情况下，在稳定、可重复的条件下生长薄膜。制备了由Al_2O_3和TiO_2层组成的增透膜，并测量了其光学特性。测试的抗反射涂层适用于532 nm和1064 nm光。残余反射率很容易得到小于0.1%，与设计值吻合较好。在1-ns、1064 nm激光脉冲下，Al_2O_3和TiO_2薄膜的激光损伤阈值分别为7 J/cm^2和3.5 J/cm^2。这些薄膜适用于激光器，但对于高功率激光器，如激光聚变，还需要一些改进。总之，所建立的化学表面反应方法在厚度和均匀性上具有良好的可控性，适用于任何大型光学仪器。它有望提高高功率激光器的激光损伤阈值。少