Inorganic positive uniaxial films fabricated by serial bideposition

The physical vapor deposition process of serial bideposition is adapted to the fabrication of uniaxial optical coatings. During the coating process the vapor impinges at an angle of incidence of about 70degrees on to the substrate, and a stepwise axial rotation with 90degrees increments causes a columnar structure to grow normal to the substrate. Symmetry considerations that follow from the choice of 90degrees for the stepwise increment ensure that the film is achiral and has negligible in-plane linear birefringence. Optical characterization techniques confirm that films of tantalum oxide, titanium oxide and zirconium oxide are positive uniaxial with n(e)-n(o) in the range 0.10 to 0.14. (C) 2004 Optical Society of America.