Resonance-based refractometric response of cladding-removed optical fibers with sputtered indium tin oxide coatings

Here it is presented the fabrication of thin and homogeneous indium tin oxide (ITO) coatings onto cladding-removed optical fibers by means of the sputtering technique. ITO coatings permit to couple light at specific resonance from the optical fiber core to the coating. Fabricated devices show a resonance shift in the visible and near infrared region when the refractive index of the surrounding medium in contact with the coating is varied, which makes possible its utilization as a refractometer. It has been also demonstrated that a post-processing of the sputtered ITO coatings by means of a thermal annealing enables to shift the resonances. Furthermore, the high attenuation of the resonances in the visible spectral range facilitates the observation of a change in the output light color, which could be useful for the fabrication of optical filters or even the determination of refractive index by means of color detection. (C) 2011 Elsevier B.V. All rights reserved.