降低薄膜的吸收对于氧化物薄膜在深紫外波段的应用具有重要意义，为此采用离子束溅射方法分别制备了用于深紫外波段的Al2O3和SiO2薄膜，利用光度法和椭圆偏振法相结合，计算得到其在190~800 nm范围内折射率n和消光系数k的色散曲线。在此基础上，以这两种氧化物材料作为高低折射率材料进行组合，设计并制备了λ/4规整膜系的193 nm多层高反射膜。实验结果表明，退火前薄膜的光学损耗相对较大，其中散射损耗较小，吸收损耗是光学损耗的主要部分。退火后光学损耗明显减小，散射损耗随着表面粗糙度增加而略微增加，表明光学损耗的减小是由吸收损耗下降所引起的。通过工艺优化，改善了氧化物薄膜在深紫外波段的损耗状况，使其在深紫外波段具有较好的光学特性，退火后高反射膜的反射率在193 nm处达96%以上。

In order to improve the absorption of oxide thin films in wavelength of deep ultraviolet (DUV), Al2O3 and SiO2 thin films for DUV are fabricated by ion beam sputtering (IBS). The refractive index n and extinction coefficient k of the thin films are obtained using spectrophotometry and ellipsometry in the 190~800 nm. High reflectance (HR) Al2O3/SiO2 coatings are designed and produced at 193 nm. After annealing, the optical loss of the coating becomes smaller. The scattering loss is much lower than the absorption loss which occupies the main role of the total loss. Oxide coatings deposit according to optimized process can have more suitable optical properties at DUV. The optical loss reduces so considerable that the reflectance of HR coatings reach more than 96% at 193 nm.