Reflection of Blue Light Using Bi-Layer Al2O3–TiO2 E-Beam Coating Films

Abstract

E-beam deposition was used to deposit Al2O3 and TiO2 single-layer films onto glass substrates at 300 °C, with 6 sccm O2 being introduced during the deposition process. Optical characterization of the films was conducted to evaluate whether the thickness was suitable for the formation of multipair reflective coatings. The refractive indices of the films measured at an optical wavelength of 450 nm were 1.742 (Al2O3) and 2.206 (TiO2). E-beam deposition was then used to deposit Al2O3–TiO2 bilayer films in one, two, four, and six periods on glass substrates to fabricate multilayer films as broadband Bragg-reflecting coatings for blue light. The thicknesses of the Al2O3 and TiO2 films for the quarter wave condition were 51 and 64 nm, respectively. When one period of Al2O3–TiO2 bilayer film was deposited on the glass substrate, the film had high transparency, and no reflective effect was observed. As two, four, and six periods were deposited on the glass substrates, the Bragg reflection effect became apparent. T...