Optical constants and dielectric permittivity of lutetium oxide films deposited with an electron gun

Lu₂O₃ films deposited by electron-beam evaporation exhibit interesting optical properties in the range 0.2 - 2 μm. The films exhibit very good transparency over a wide spectral range. Only a very small influence of the deposition pressure as well as thermal annealing of specimens on optical properties was observed. Refractive index and its dispersion over a wide spectral region was determined. Films exhibit only a weak absorption in violet and ultraviolet ranges. The high-frequency dielectric permittivity was estimated. Thin films of LU₂O₃ can be useful for thin-film optics. Lu₂O₃-Si antireflection coatings were fabricated. These coatings reduce reflectivity of silicon-based photocells from 35% at λ=0.56 μm down to 0.9%