Sputtering Deposition of TiO<sub>2</sub> Thin Film Coatings for Fiber Optic Sensors
Daniela Silva,
Catarina S. Monteiro,
Susana O. Silva,
Orlando Frazão,
Joana V. Pinto,
Maria Raposo,
Paulo A. Ribeiro,
Susana Sério
Affiliations
Daniela Silva
Department of Physics, NOVA School of Science and Technology, NOVA University Lisbon, 2829-516 Almada, Portugal
Catarina S. Monteiro
Department of Engineering Physics, Faculty of Engineering, University of Porto, R. Dr. Roberto Frias, s/n, 4200-465 Porto, Portugal
Susana O. Silva
Centre for Applied Photonics, Institute for Systems and Computer Engineering, Technology and Science (INESC TEC), Rua do Campo Alegre, 687, 4150-179 Porto, Portugal
Orlando Frazão
Centre for Applied Photonics, Institute for Systems and Computer Engineering, Technology and Science (INESC TEC), Rua do Campo Alegre, 687, 4150-179 Porto, Portugal
Joana V. Pinto
i3N/CENIMAT, Department of Materials Science, NOVA School of Science and Technology and CEMOP/UNINOVA, NOVA University Lisbon, Campus de Caparica, 2829-516 Caparica, Portugal
Maria Raposo
Laboratory of Instrumentation, Biomedical Engineering and Radiation Physics (LIBPhys-UNL), Department of Physics, NOVA School of Science and Technology, NOVA University Lisbon, 2829-516 Caparica, Portugal
Paulo A. Ribeiro
Laboratory of Instrumentation, Biomedical Engineering and Radiation Physics (LIBPhys-UNL), Department of Physics, NOVA School of Science and Technology, NOVA University Lisbon, 2829-516 Caparica, Portugal
Susana Sério
Laboratory of Instrumentation, Biomedical Engineering and Radiation Physics (LIBPhys-UNL), Department of Physics, NOVA School of Science and Technology, NOVA University Lisbon, 2829-516 Caparica, Portugal
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.
