VUV optical coatings and film materials

研究了真空紫外光学薄膜的沉积方法，用热舟蒸发制备了LaF3, NdF3, GdF3高折射率材料单层膜和MgF2, A1F3, Na3A1F6低折射率材料单层膜，研究了基底温度和沉积速率对薄膜微观结构的影响。分析了薄膜的微观结构如横截面形貌、表面形貌、晶体结构对薄膜的光学常数、光学损耗以及应力等的影响。要得到光学特性优良的薄膜，氟化物薄膜最好沉积在较高温度的基底上。沉积速率对光学薄膜的影响不如基底温度的影响那么明显，速率太快和太慢都不利于低损耗薄膜的沉积。研究表明，除了冰晶石薄膜，大部分薄膜沉积在3000C温度的基底上，能得到结构致密、高透过率和低光学损耗的薄膜。Fluoride optical coatings in vaccum-ultraviolet have been researched. High-refractive-index materials such as LaF3, NdF3, GdF3, and low-refractive-index materials such as MgF2, A1F3, Na3A1F6 were deposited by a mol沙denum boat evaporation process. Microstructures that formed under different substrate temperature and deposition rate were investigated. The relation between their microstructures (including cross section morphology, surface roughness and crystalline structure), the optical properties (including refractive index and optical loss) and mechanical properties (stress) were investigated. To obtain better optical characteristics, Fluoride material films should be deposited at a higher substrate temperature and a appropriate deposition rate. It is shown that most fluoride materials, except Na3A1F6, deposited on the 300 0C substrate temperature, can obtain good films with high transmittance and little optical loss at 193 nm and 157nm