Optical anisotropy of TiO2 and MgF2 thin films prepared by glancing angle deposition

In this paper, the relationship between the optical anisotropy and. the columnar microstructure in TiO2 and MgF2 thin films deposited by glancing angle deposition (CLAD) and the effects of the optical anisotropy of the films on the refractive index and the microstructure are investigated. The results show that as the glancing angle increases, the column angle and the porosity of the TiO2 and the MgF2 films increase due to the shadow effects, and the refractive index decreases. The optical anisotropy of the tilted and the zigzag structures of TiO2 films reaches a maximum at a glancing angle of 60 degrees. TiO2 films deposited during rotation of the substrate at a high glancing angle show a small anisotropy due to the symmetry of the helical microstructure. On the other hand, the anisotropy of MgF2 film deposited by using GLAD is very small, nearly isotropic, due to the low refractive index of MgF2. We found that the microstructure, as well as the refractive index of film, plays an important role in the optical anisotropy of the thin films deposited by using GLAD.