Values of the transmittance <i>T</i><sub><i>s</i></sub> and the phaseretardation Δ were recorded <i>in situ</i> at two angles duringthe growth of thin films of tantalum oxide, titanium oxide, andzirconium oxide for deposition angles θ<sub>ν</sub> in the range40°–70°. Column angles for the same films were determined<i>ex situ</i> from scanning electron microscopy photographs ofdeposition-plane fractures. We show that the experimental columnangles are smaller than the corresponding values predicted by thetangent-rule equation ψ = tan<sup>−1</sup>(0.5 tan θ<sub>ν</sub>) and that the experimental values fit a modifiedform of the equation ψ = tan<sup>−1</sup>(<i>E</i><sub>1</sub> tan θ<sub>ν</sub>) where <i>E</i><sub>1</sub> is less than 0.5. We also show that theprincipal refractive indices are represented well by quadraticfunctions of the deposition angle, for example, <i>n</i><sub>1</sub>(θ<sub>ν</sub>) = <i>A</i><sub>0</sub> + <i>A</i><sub>2</sub> θ<sub>ν</sub><sup>2</sup>.
© 1998 Optical Society of America
Ian Hodgkinson, Qi hong Wu, and Judith Hazel, "Empirical Equations for the Principal Refractive Indices and Column Angle of Obliquely Deposited Films of Tantalum Oxide, Titanium Oxide, and Zirconium Oxide," Appl. Opt. 37, 2653-2659 (1998)