Description du sujet de thèse

ICB laboratory offers a PhD fellowship (CNRS) on nonlinear optical waveguides and resonators based on tellurite and chalcogenide glasses for chemical sensing into the mid-infrared. Mid Infrared (MIR), from 2 to 20 µm, is an attractive spectral range for many applications, particularly in sensing, as it matches with chemical bond resonances. Atmospheric pollutants, explosive substances and biological liquids among other can be targeted.

ICB has strong expertise in IR fiber based on heavy oxides and chalcogenide glasses, which exhibit wide transmission in this range and strong nonlinear optical properties. Mid-IR laser sources based on nonlinear optics in chalcogenide (S, Se and Te-based glasses) and tellurite (TeO2) fibers have been developed at ICB. Supercontinuum generation in such fibers has led to a sup-100 mW IR source covering the 1-16 µm range [1]. Proof-of-concept experiments have demonstrated the potential of such fibered IR sources for CH4 sensing up to 8 µm at ppm level [2]. The goal of the project is now to extend the potentialities of chalcogenide and tellurite glasses by shaping them into functionalized devices such as optical tapers or microresonators. In this context, a funded international ANR (France) – FAPESP (Brazil) project has been secured in collaboration with the Institute of chemistry of Sao Carlos (IQSC) from University of Sao Paulo to develop mid IR fibered sensors. The PhD thesis will build on the team's previous results to develop mid IR fiber-optic sensors that can act both as an IR light source (via supercontinuum generation) and as a sensing element. The strategies being considered relate to fiber geometry and fiber surface engineering.
Fibers with a locally reduced diameter, known as tapers, strongly enhance the confinement of the electromagnetic field, and therefore facilitate the generation of new wavelengths as well as sensing through evanescent wave spectroscopy. They have already yielded promising results [3] and work in this direction will be continued. Microspheres that enable both resonators fabrication and sensing, for which promising preliminary results have already been obtained, will also be considered. Numerical analysis, based on codes developed at ICB, will guide the investigations towards the development of Raman and Brillouin laser, supercontinuum and Kerr frequency comb generation.

Another strategy of the project is to amplify the signal propagating at the surface of the glass fiber using chemical approach in collaboration with our Brazilian partner, who has developed a technique to coat the glass with a rare-earth-containing metal organic framework (Ln-MOF) that allow for ratiometric (intensities ratio fluctuation) sensing through energy transfer between the ligands and the rare earth [4]. The glass fiber surface can also be leveraged through physical phenomena based on plasmonic resonances. The deposition of a structured metallic nanolayer onto the glass fiber surface, with controlled morphology, leads to localized surface plasmon resonances which strongly enhanced the near field confined at the fiber surface [5]. This near field interacts with adsorbed molecules, resulting in an enhanced response for both Raman scattering and IR absorption. Both phenomena will be investigated.

ICB facilities allow for glass synthesis and fiber fabrication (2 drawing towers), post processing operation (such as taper and microsphere fabrication) and linear/nonlinear optical characterization as well as ultrafast pulsed regimes in the IR range (form near IR up to 22 µm) within the Smartlight platform. Deposition of structured metal nanoparticles will be carried out using ICB's facilities (ARCEN technological platform). Our Brazilian partner, IQSC, is highly skilled in rare earth spectroscopic characterizations and glass surface functionalization through MOFs coating and chemical nanoparticle deposition with controlled morphology.

Depending on the candidate's profile and interests, the subject will focus either on material or optical aspects. Applicants should have a good background in materials science (physical chemistry of materials) or optics and physics. Experience in glass synthesis, cleanroom work, thin metallic film deposition or numerical simulation would be an advantage. The candidate should possess good English communication skills, both oral and written.

Submittals
• Letter of recommendation
• Cover letter
• Curriculum vitae
• Transcripts of academic results
[1] E. SERRANO, D. BAILLEUL, F. DÉSÉVÉDAVY, P. BÉJOT, G. GADRET, P. MATHEY, F. SMEKTALA, AND B. KIBLER, Accepted in Photonics Research, (2024).
[2] R. BIZOT, I. TILIOUINE, F. DÉSÉVÉDAVY, G. GADRET, C. STRUTYNSKI, E. SERRANO, P. MATHEY, B. KIBLER, S. FÉVRIER, AND F. SMEKTALA, APL Photonics, 9, No. 11.
[3] D. BAILLEUL, E. SERRANO, B. MAHLOOVANYI, C. BROUSSARD-PLEDEL, L. C. DAVID, F. DÉSÉVÉDAVY, P. MATHEY, G. GADRET, C. STRUTYNSKI, Y. MESSADEQ, F. SMEKTALA, AND B. KIBLER, Submitted to Applied Optics, (2025).
[4] R. G. CAPELO, C. STRUTYSK, F. DÉSÉVÉDAVY, F. SMEKTALA, AND D. Manzani, Anais, (2024).
[5] J. KOZUCH, K. ATAKA, AND J. HEBERLE, Nature Reviews Methods Primers, 3, No. 1, (2023).

Contexte de travail

This PhD thesis will be conducted within the framework of an international collaboration between the ICB laboratory and the University of São Paulo (Brazil), supported by the ANR (AAPG 2024 project call, RAISES 24-CE08-4812).
This position is funded for 36 months and is expected to start between 1st of September and 31st of December 2025.

ICB's interdisciplinary research spans a continuum from fundamental science to applied technologies. This approach enables the development of new materials, their design through numerical simulation, and their physical and chemical characterization. Areas of study include nonlinear optical effects, ultrafast pulsed optics, and the physicochemical analysis of interfaces (AFM, XPS, SIMS), as well as near-field characterizations such as SNOM.

Its specialized activities cover a wide range of fields including optical and electron microscopy, optical fibers, lasers, quantum nanophotonics, nanomedicine, surface and interface analysis, chemical reactivity, and the characterization and development of materials (processes, fuel cells, powder metallurgy, additive manufacturing, sintering, cements, sensors, and non-destructive testing). These activities are supported by five technological platforms.

The laboratory's multidisciplinary expertise is leveraged for research projects and made available to regional, national, and international innovation hubs and industries.

Le poste se situe dans un secteur relevant de la protection du potentiel scientifique et technique (PPST), et nécessite donc, conformément à la réglementation, que votre arrivée soit autorisée par l'autorité compétente du MESR.