title: Optimization of thickness uniformity of optical coatings on a conical substrate in a planetary rotation system.
abstract: For a coating machine with a planetary rotation system and counterrotating shadowing mask configuration, a shadowing mask was designed using a numerical optimization algorithm to control the thickness uniformity of optical coatings formed on conical substrate. Single-layer magnesium fluoride (MgF(2)) and antireflective (AR) coating at 193 nm were fabricated on a convex conical substrate holder (with diameter 225 mm, apex angle 140 deg, and height 41 mm) by thermal evaporation. Thickness distribution determined from the transmittance spectra of single-layer MgF(2) thin films on BK7 slices showed that uniformities better than 99.3% were experimentally achieved with the designed counterrotating shadowing mask. From the reflectance spectra, uniform optical performance was also obtained for the 193 nm AR coating deposited on fused-silica substrates.
authors: Institute of Optics and Electronics, Chinese Academy of Sciences, Chengdu, China.
authors: Chun
authors: C
authors: Guo
authors: Mingdong
authors: M
authors: Kong
authors: Cunding
authors: C
authors: Liu
authors: Bincheng
authors: B
authors: Li