TiO_2 nanoparticle thin film-coated optical fiber Fabry-Perot sensor

Abstract

In this paper, a novel TiO(2) nanoparticle thin film coated optical fiber Fabry-Perot (F-P) sensor had been developed for refractive index (RI) sensing by monitoring the shifts of the fringe contrast in the reflectance spectra. Using in situ liquid phase deposition approach, the TiO(2) nanoparticle thin film could be formed on the fiber surface in a controlled fashion. The optical properties of as-prepared F-P sensors were investigated both theoretically and experimentally. The results indicated that the RI sensitivity of F-P sensors could be effectively improved after the deposition of nanoparticle thin-films. It was about 69.38 dB/RIU, which was 2.6 times higher than that of uncoated one. The linear RI measurement range was also extended from 1.333~1.457 to 1.333~1.8423. More importantly, its optical properties exhibited the unique temperature-independent performance. Therefore, owing to these special optical properties, the TiO(2) nanoparticle thin film coated F-P sensors have great potentials in medical diagnostics, food quality testing, environmental monitoring, biohazard detection and homeland security, even at elevated temperature.

High Sensitivity Refractive Index Sensor by D-Shaped Fibers and Titanium Dioxide Nanofilm

“…The thin film coatings combined with side-polished optical fibers can produce two different resonance types: one is surface plasmon resonances (SPRs) [8] and the other is lossy mode resonances (LMRs) [9][10][11]. The surface plasmon resonance (SPR) occurs when the real part of the thin film permittivity is negative and higher in magnitude than both its own imaginary part and the permittivity of the material surrounding the thin films.…”

“…The effects of depositing a thin, highly refractive index (RI) layer onto the cladding over the grating region have been reported [8,9]. Since titanium dioxide (TiO 2 ) is one of the highly refractive index materials, TiO 2 is known to be a good photocatalytic material under UV radiation.…”

An in-line optical fiber refractometer with porous thin film coating

“…The former includes fiber Bragg gratings (FBGs) [1][2][3][4][5], and long period gratings (LPGs) [6][7][8], in which the resonant wavelengths of gratings depend on RI of external environment due to the mode coupling. While the later includes interference structure such as Mach-Zehnder (M-Z) interferometer [9][10][11] and Fabry-Perot (F-P) interferometer [12][13][14][15][16][17][18][19][20].…”

Optical fiber-based sensor for in situ monitoring of cadmium sulfide thin-film growth

“…Optical interferometry techniques [11], particularly Fabry-Perot interferometric fiber-based optical sensors [12], have been utilized for optical characterization of thin films. The use of fiber optics allows sensing in toxic biological reactions [13] or gases [8].…”

“…Both methods depend on laser light illumination; however, they need dark chamber setup and both the techniques are sensitive to vibration. To improve the sensitivity of the fiber-based sensors, high refractive index material, like TiO 2 , coated fiber tips have also been used recently, and more than 2 times higher sensing sensitivity has been demonstrated compared to the uncoated fiber tips [12]. However, this method needs the coated fiber tips to be immersed directly into the measured medium during sensing, which is not suitable in case of the corrosive deposition solutions.…”