Inorganic positive uniaxial films fabricated by serial bideposition

Abstract

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 70 on to the substrate, and a stepwise axial rotation with 90 increments causes a columnar structure to grow normal to the substrate. Symmetry considerations that follow from the choice of 90 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 ne -no in the range 0.10 to 0.14.

A Birefringent and Transparent Electrical Conductor

“…For example, the vertical posts shown in Figure 3e were produced by holding the substrate at a fixed deposition angle of a ¼ 858 while continuously and rapidly rotating in w. These conditions produce a microstructure which is optically uniaxial and exhibits large birefringence values out of the plane of the substrate. [15,16] Alternatively, the vertical columns shown in Figure 3f were fabricated by holding the substrate at a fixed deposition angle of a ¼ 858 while rapidly rotating about w in steps of 1808. This process is commonly referred to as serial bideposition (SBD) and results in vertical columns with a pronounced elliptical cross-section (typical cross-sectional profiles for the vertical uniaxial and vertical biaxial structures are provided in the insets of Fig.…”

Optical properties of phase shift on reflection and/or transmission through biaxial anisotropic thin films

“…Three-dimensional nanostructured anisotropic sculptured thin films (STFs) [1] prepared via GLAD technique resemble an artificial material with interesting optical properties and are extensively adopted in designing and developing optical components, including phase retardation devices [2,3], polarization converter [4], polarization-selective beam splitters [5], and broadband antireflective coatings [6] etc. In addition, such films deposited in a controllable manner during growth process that the nanocolumn microstructures exhibit continuum and anisotropic characteristics, but the molecules and clusters of small size retain their individuality.…”

Use of <inline-formula><math display="inline" overflow="scroll"><mrow><msub><mrow><mi>Ta</mi></mrow><mrow><mn>2</mn></mrow></msub><msub><mrow><mi mathvariant="normal">O</mi></mrow><mrow><mn>5</mn></mrow></msub></mrow></math></inline-formula> biaxial thin film as a high-efficiency polarization converter

“…This method utilizes physical vapor deposition to deposit films on a substrate that is tilted at a deposition angle to the vapor source. 1, the birefringence properties of these films originate from the nanostructure and the orientation of the three principal axes (1,2,3) so that axis 1 is in the columnar growth direction; axis 2 is in the deposition plane; and axis 3 is perpendicular to the deposition plane, i.e., the plane defined by the surface normal and the columns. Deposition angle α refers to the angle between substrate normal and the incident direction of the vapor flux, while column angle β refers to the angle between substrate normal and the direction of column growth.…”