LaF3/MgF2 reflection filters with a high spectral-discrimination capacity of the atomic-oxygen lines at 130.4 and 135.6 nm, which were employed in vacuum ultraviolet imagers, were prepared by molybdenum-boat thermal evaporation. The optical properties of reflection filters were characterized by a high-precision vacuum ultraviolet spectrophotometer. The vulnerability of the filter's microstructures to environmental contamination and the recovery of the optical properties of the stored filter samples with ultraviolet ozone cleaning were experimentally demonstrated. For reflection filters with the optimized nonquarter-wave multilayer structures, the reflectance ratios R-135.6nm/R-130.4nm of 92.7 and 20.6 were achieved for 7 degrees and 45 degrees angles of incidence, respectively. On the contrary, R135.6nm/R130.4nm ratio of 12.4 was obtained for a reflection filter with a standard p-stack multilayer structure with H/L = 1/4 at 7 degrees AOI. (C) 2015 Optical Society of America
英文摘要:
LaF3/MgF2 reflection filters with a high spectral-discrimination capacity of the atomic-oxygen lines at 130.4 and 135.6 nm, which were employed in vacuum ultraviolet imagers, were prepared by molybdenum-boat thermal evaporation. The optical properties of reflection filters were characterized by a high-precision vacuum ultraviolet spectrophotometer. The vulnerability of the filter's microstructures to environmental contamination and the recovery of the optical properties of the stored filter samples with ultraviolet ozone cleaning were experimentally demonstrated. For reflection filters with the optimized nonquarter-wave multilayer structures, the reflectance ratios R-135.6nm/R-130.4nm of 92.7 and 20.6 were achieved for 7 degrees and 45 degrees angles of incidence, respectively. On the contrary, R135.6nm/R130.4nm ratio of 12.4 was obtained for a reflection filter with a standard p-stack multilayer structure with H/L = 1/4 at 7 degrees AOI. (C) 2015 Optical Society of America
