SEMINAR LMGP - June 14, 2022 - Ibtihel MARZOUK

Ibtihel MARZOUK

PhD student,
Univ. Grenoble Alpes, CNRS, Grenoble INP, LMGP, F-38000, Grenoble, France
Univ. Grenoble Alpes, CNRS, Grenoble INP, IMEP-LAHC, F-38000, Grenoble, France

Abstract

We present a fluorescent wave-guiding micro-structured architecture on glass entirely elaborated by sol-gel processing. This architecture is composed of a channel waveguide doped with an oxygen sensitive fluorophore (Rudpp) and endowed with diffraction gratings. It particularly takes advantage of a high refractive index titanium oxide based sol-gel photoresist that can be imprinted through a single photolithography step. The gratings enable to inject the green excitation signal in the axis of the waveguide core and to extract the red signal emitted by Rudpp toward a photodetector. We firstly present the multi-step elaboration process leading to this architecture. Opto-geometrical properties of the channel waveguide and diffraction gratings are assessed and optimized on the basis of optical and AFM characterizations. According to these properties, best injection and extraction angles of the excitation and emission signals have been determined thanks to optical simulation. Then, we present fluorescence measurements performed in wave-guiding configuration using a specifically designed optical bench. These measurements demonstrate that the waveguide enables efficient propagation of light at the excitation and emission wavelengths of the fluorophore and that the diffraction gratings are compatible with efficient injection and extraction of the excitation and emission signals. This work constitutes a promising first step towards a new class of oxygen sensors based on the well-known principle of oxygen driven extinction of the Rudpp fluorescence.