[13a-2A-1~10] 3.2 Equipment optics and materials

△ [13a-2A-9] Low-temperature Preparation of High-n Rutile-type TiO₂ Thin Films and Their Application to Optical Coatings

〇(M2)Akihiro ISHII¹, Itaru OIKAWA¹, Masaaki IMURA², Toshimasa KANAI², Hitoshi Takamura¹ (1.Tohoku Univ., 2.Nippon Electric Glass)

Keywords:Optical coatings,High refractive index,TiO2 thin films

A rutile-type TiO₂ thin film with high refractive index is highly demanded to improve the reflection properties of optical coatings (e.g. antireflection coatings and dielectric mirrors), and also expected to extend their design flexibility; however, at this moment, the rutile-type TiO₂ thin films is difficult to prepare below 700°C as a single phase. This high temperature processing leads to rough surface morphology and poor optical properties. This study proposes a new way to control the crystal growth of TiO₂ thin films by Al doping, which enables a low-temperature preparation of the rutile-type TiO₂ thin films. In addition, a dielectric mirror was fabricated using the high refractive Al-doped rutile-type TiO₂ thin films, and their reflection properties will be presented.