Study on Brewster angle thin film polarizer using hafnia-silica mixture as high-refractive-index material

摘要

Two kinds of polarizer coatings were prepared by electron beam evaporation, using HfO_2 - SiO_2 mixture and HfO_2 as the high-refractive-index materials, respectively. The HfO_2 - SiO_2 mixture layer was implemented by coevaporating SiO2 and metal Hf, the materials were deposited at an oxygen atmosphere to achieve stoichiometric coatings. The certain HfO_2 and SiO_2 content ratio is controlled by adjusting the deposition rate of HfO_2 and SiO_2 using individual quartz crystal monitor. The spectral performance, surface and interfacial properties, as well as the laser-induced damage performance were studied and compared. Comparing with polarizer coating using HfO_2 as high-refractive-index material, the polarizer coating using HfO_2 - SiO_2 mixture as high-refractive-index material shows better performance with broader polarizing bandwidth, lower surface roughness, better interfacial property while maintaining high laser-induced damage threshold.