An approach for determining the optical constants of the weakly absorbing substrate is developed and applied to obtain the parameters of CaF2 and fused silica substrates in deep ultraviolet (DUV) and vacuum ultraviolet (VUV) range. A method for extracting the optical constants of thin films deposited on strongly absorbing substrate, which is based on the reflectance spectra measured at different angles of incidence, is also presented. The optical constants are determined by fitting the measured spectra to the theoretical models. The proposed method is applied to determine the refractive index and extinction coefficient (n, k) of MgF2 film deposited on silicon substrate by electron beam evaporation with substrate temperature 300 oC and deposition rate 0.2 nm/s. The determined n, k values at 193 nm are 1.433 and 9.1 \times 10-4, respectively.

We report the simulation results on the thickness uniformity of optical coatings deposited on spherical substrates by optimizing the geometric configuration parameters, such as tilting angle of the substrate holder and position of the evaporation source in a 1 000-mm-diameter planetary rotation stage (PRS). We reveal that good film uniformity on convex spherical surfaces or flat substrates, as well as concave surfaces with weak to moderate curvatures can be obtained through appropriate tilting of the substrate holder. For 300-mm-diameter substrates with clear aperture to radius of curvature (CA/RoC) between -0.3 and 0.7, the achievable film uniformity is above 99%. The source position is optimized to achieve good film uniformity.

分别建立了真空镀膜机行星系统中平面光学元件薄膜厚度模型和修正挡板校正薄膜厚度非均匀性模型，并运用数值计算方法完成修正挡板优化设计；研究了使用修正挡板校正薄膜厚度分布时平面行星夹具上热蒸发薄膜材料的沉积效率。实验结果表明：依据修正挡板校正薄膜厚度非均匀性模型优化设计的修正挡板能使口径为310 mm、无倾斜放置的平面行星夹具上，由电子束热蒸发工艺制备的MgF2薄膜厚度均匀性优于99.6%，并且热蒸发MgF2薄膜材料的沉积效率高于87.4%。