Development of a polymer-lanthanide composite for deposition on optical fiber tip surface by 3D printing

Abstract

Optical fibers have been used for many applications due to their features like immunity to electrical interference, miniaturization, bending flexibility, remote and on-time acquisition of data for inaccessible locations or harsh environments. In general, optical fibers are used in sensing to guide the signal to the detectors. However, in the last few years, chemical and physical modification processes on the optical fibers have allowed them also to act as a sensing platform. Distinct types of modifications are performed on core and cladding regions, including processes to change the fiber itself, such as physical stretching or chemical modification by deposition of optical active substances. Many types of materials have already been used as surface modifiers, as graphene oxide, metallic nanoparticles, Molecular Imprinted Polymers, and so on for varied applications in temperature sensing, pressure, or volatile organic compounds. However, a good control of the deposited material, etching or tapering processes, the limit of detection, sensitivity, and complex structures on the surface of the optical fiber are topics still to be investigated. One of the promising approaches is the micro and nanofabrication by 3D printing on the top end of optical fibers. This method allows a great control over thickness, geometry, and distribution, as much as eliminating the step of removing part of the cladding or tapering the fiber, a problem for reproducibility of the sensing platform. In this sense, this project aims to build a polymeric microstructure on the tip of a multimode silica-based optical fiber using a Nanoscribe GT2 printing, combining the resin with a RE3+ complex (Eu/Tb and Er/Yb) as benzyl-carboxylic acid derivatives in which the ligand act as sensitizer for the rare-earth luminescence. The optical properties such as emission and excitation spectra, or lifetime measurements, will be analyzed in different temperatures for optical luminescent thermometry. (AU)