Sputtering Deposition of TiO2 Thin Film Coatings for Fiber Optic Sensors

Thin films of titanium dioxide (TiO2) and titanium (Ti) were deposited onto glass and optical fiber supports through DC magnetron sputtering, and their transmission was characterized with regard to their use in optical fiber-based sensors. Deposition parameters such as oxygen partial pressure, working pressure, and sputtering power were optimized to attain films with a high reflectance. The films deposited on glass supports were characterized by UV-Vis spectroscopy, X-ray diffraction (XRD), and scanning electron microscopy (SEM). Regarding the deposition parameters, all three parameters were tested simultaneously, changing the working pressure, the sputtering power, and the oxygen percentage. It was possible to conclude that a lower working pressure and higher applied power lead to films with a higher reflectance. Through the analysis of the as-sputtered thin films using X-ray diffraction, the deposition of both Ti and TiO2 films was confirmed. To study the applicability of TiO2 and Ti in fiber sensing, several thin films were deposited in single mode fibers (SMFs) using the sputtering conditions that revealed the most promising results in the glass supports. The sputtered TiO2 and Ti thin films were used as mirrors to increase the visibility of a low-finesse Fabry-Perot cavity and the possible sensing applications were studied.

Automated summary

Thin films of titanium dioxide (TiO2) and titanium (Ti) were deposited on glass and optical fiber supports via DC magnetron sputtering. The transmission characteristics were characterized for their use in optical fiber-based sensors. Optimization of deposition parameters resulted in high reflective films, with lower working pressure and higher applied power leading to higher reflectance. X-ray diffraction analysis confirmed the deposition of Ti and TiO2 films. Deposition of the most promising films on single mode fibers enhanced visibility of low-finesse Fabry-Perot cavities, and potential sensing applications were studied.