Optical Devices Based on Chalcogenide Glasses for Mid- and Far-Infrared Supercontinuum Generation

Context : This PhD project is part of the ANR FIRST-LIGHT program, which aims to develop compact, ultra-broadband light sources and sensors covering both the mid- and far-infrared regions, using advanced glass and optical fiber technologies combined with state-of-the-art laser systems. The project seeks to bridge the gap between recent advances in mid-infrared photonics and the terahertz domain, recognizing the far-infrared (12–50 µm) as a major remaining frontier in the electromagnetic spectrum. This multidisciplinary effort lies at the interface of materials chemistry, nonlinear optics, and spectroscopy. It focuses on advancing the state of the art by developing novel nonlinear optical glasses, controlling broadband frequency conversion processes driven by ultrashort laser pulses, and enabling fiber-based platforms for far-infrared spectroscopy.

Methodology and tasks : The PhD candidate will be responsible for the synthesis, optimization, and purification of Te-rich chalcogenide glasses for far-infrared optical applications, starting from existing reference compositions and extending toward novel tellurium-halide systems to widen the transmission window up to 40–50 µm. The work will involve materials engineering to improve glass-forming ability and resistance to crystallization, alongside the implementation of high-purity synthesis protocols under vacuum and advanced purification techniques (thermal treatments, getters, distillation) to minimize optical losses. The candidate will fabricate bulk glass samples and preforms, and subsequently develop optical fibers with various geometries (multimode, single-mode, suspended-core, step-index), using different processing techniques such as rod-in-tube drawing, tapering, and co-extrusion, while addressing challenges related to thermal stability and loss reduction (target ≈ 1 dB/cm up to 25 µm). In parallel, the candidate will carry out comprehensive characterization of the materials and fibers, including thermal, structural, linear and nonlinear optical properties, using a wide range of experimental techniques (DSC, FTIR, ellipsometry, z-scan, microscopy, Raman spectroscopy). Additional experimental setups will be developed to measure dispersion, nonlinear coefficients, and laser-induced damage thresholds in the mid- and far-infrared. Finally, the candidate will analyze and compare the results with literature data and numerical models in order to validate material performance and guide further optimization.

The Institut des Sciences Chimiques de Rennes (ISCR) is a joint Research Department (UMR: Unité Mixte de Recherche) associating the CNRS (INC et INSIS), The Université de Rennes, the Ecole Nationale Supérieure de Chimie de Rennes (ENSCR) and the Institut National des Sciences Appliquées de Rennes (INSA de Rennes).

This Institute, founded in January 1st, 2006, gathers together all the academic forces in chemistry from the Rennes site. At the beginning of 2026, it brings together more than 270 permanent people, including approximately 140 assistant-professors and professors, 60 CNRS researchers and 80 engineers and technicians, at the Rennes Beaulieu, Rennes Villejean and Lannion IUT sites, leading to an overall workforce of more than 500 people. 

Master’s degree (Bac +5, engineering degree, research Master’s or equivalent level) with a specialization in Materials Science. Skills in synthesis under inert atmosphere, optics, and/or optical materials will be appreciated. A strong interest in experimental work is essential.