Materials for the fabrication of optical fiber refractometers based on lossy mode resonance

Lossy mode resonances (LMR) have been studied as an exceptional phenomenon for the development of optical fiber refractometers. These sensors rely on the interaction of the light propagating through the waveguide with a thin-film fabricated onto it. The properties of such film will determine the sensitivity of the LMR to surrounding refractive index variations. The nature of the film will also play an important role on the possibilities to develop sensing applications. This thesis analyzes the use of four different materials (tin oxide, aluminum-doped zinc oxide, indium-gallium-zinc oxide and copper oxide) for the development of LMR-based refractometers. First, the optimization on the fabrication process of tin oxide coatings is described, with the purpose of maximizing the sensitivity in a refractive index range close of the fused silica (1.44). Then, materials based on zinc oxide are presented for the first time for the fabrication of LMR-based sensors: aluminum-doped zinc oxide (AZO) and indium-gallium-zinc oxide (IGZO), leading to the development of several sensors working in the visible and near-infrared wavelength range. The last material analyzed in this work is copper oxide, which presents a refractive index considerably larger than the previously studied materials. Such feature is suggested to provide a greater sensitivity of the LMR to SRI variations, promising a better performance than the one achieved with different thin-films.