Preparation of a dense TiO2 thin film by oxidizing metallic titanium

We prepared a dense rutile TiO2 thin film that has a refractive index as high as that of the bulk crystal by oxidizing metallic Ti thin film. The TiO2 thin film with a thickness of 260 nm is optically transparent and has low coefficients of absorption and scattering. We annealed a Ti thin film at 1000 °C for oxidation and crystallization after deposition of metallic Ti by electron-beam evaporation. By optimizing the annealing conditions, we obtained a rutile TiO2 thin film with a refractive index of 2.72 at a wavelength of 1030 nm, the highest refractive index ever reported.