Sol–gel planar waveguides for improved fluorescence microarrays

• Published in: Thin solid films Vol. 518; no. 15; pp. 4450 - 4457
• Main Authors: Bedu, Mélanie, Sagarzazu, Gabriel, Gacoin, Thierry, Audebert, Pierre, Weisbuch, Claude, Martinelli, Lucio
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 31-05-2010; Elsevier
• Subjects: Annealing; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Constraining; Cross-disciplinary physics: materials science; rheology; Evanescent waves; Exact sciences and technology; Fluorescence; Fundamental areas of phenomenology (including applications); Liquid phase epitaxy; deposition from liquid phases (melts, solutions, and surface layers on liquids); Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Microarray; Optical materials; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of specific thin films; Optics; Physics; Planar waveguides; Real time; Refractive index; Refractivity; Sol gel process; Sol–gel; Structure and morphology; thickness; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Thin film structure and morphology; Titanium dioxide; Titanium oxide; Fluorescence; Optical materials; Planar waveguides; Microarray; Sol–gel; Titanium oxide; Annealing; Refractive index; Sol-gel; Signal-to-noise ratio; Hybridization; Real time; Heat treatments; Implementation; Fluorescent material; Optical properties; Reaction kinetics; Waveguides; Acetic acid; Microstructure; Sol-gel process
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2010.02.026

The real-time monitoring of the hybridization signal, giving access to the reaction kinetics, can widen the results of a microarray experiment. Nevertheless, the presence of a strong fluorescent mix often degrade the experimental sensitivity, limiting the interest of this technique: the implementation of an evanescent wave excitation scheme can represent in this case a real advantage. In this paper, we propose high refractive index waveguides fabricated by sol–gel process for evanescent wave microarray applications. The influence of the sol composition and annealing parameters on materials microstructure are carefully studied to obtain good optical properties and high refractive index (
n
=
1.8–2.1) using thermal treatments below 250
°C. Monomode TiO
2 planar waveguides chelated by acetic acid are used as substrates for waveguide-based microarray in real-time experiments, demonstrating a significant increase of the signal to noise ratio.