Chalcogenide glasses offer transmission windows within the far-visible, near- and midinfrared (IR) range. They exhibit potentially excellent linear and large non linear optical properties, photosensitivity and their low phonon energies are conducive to efficient dopant rare earth transitions. These properties enable many potential infrared applications: large-scale optics; fibreoptics; integrated optics; optical imaging; optical data storage and all-optical switching. Two lines of experimental work were followed in this project based on chalcogenide glasses, as below: (1) Antimony was used to replace arsenic, to fOIm the ternary Ge-Sb-Se glass system. Nine compositions of Ge-Sb-Se glasses were synthesised and characterised to reveal their glass forming abilities, thermal properties and optical properties. Glass pairs, with close thermal propeIties and relatively high refractive index contrast, were developed for fabricating core-clad. structure step index fibre and micro structured optical fibres (MOFs). (2) Fabrication of an all-solid chalcogenide glass micro structured fibre (MOF), which was designed as a mimic of the holey suspended structure silica MOF, was canied out. A cane-drawing technique and a real-time contactless diameter monitor of the chalcogenide canes were developed to improve the precision of the fabrication. Stacking equipment was designed to improve the technique of the chalcogenide preform stacking.

The problem of residual stress measurement in industrially manufactured tempered glass components has been addressed by the development and application of an experimental stress analysis technique known as pulsed magneto-photoelasticity. In the manufacture of tempered glass, residual stress is intentionally introduced in order to strengthen the material. However, the exact nature of the stress distribution remains unknown and, as a consequence, the strength of tempered glass products can vary significantly. A pulsed magneto-polariscope has been developed to allow the residual stress in glass to be quantified both through the thickness of the material and over the surface plane. Developments to the theory of the technique have enabled optical data, collected in the presence of multiple magnetic fields, to be used to provide a more detailed analysis of the residual stress distribution than has previously been possible. In the first phase of development, a pulsed magneto-polariscope with a continuous bore solenoid coil was designed and constructed. This enabled the proposed developments to be validated by testing birefringent specimens of epoxy resin and sectioned tempered glass test specimens. In addition, computer programs were developed to reduce the experimental complexity of the technique and to provide a platform upon which further research can be undertaken. The technique was extended by the design and inclusion of a novel component termed the dual coil solenoid which enabled high instantaneous magnetic flux densities to be generated, homogenously, over a wo.rking volume thereby allowing industrially manufactured tempered glass products to be analysed. Furthermore, this enabled test specimens of glass to be placed under known loads in order to precisely validate the proposed methodology. The pulsed magneto-polariscope was used to successfully quantify the residual stress distribution within a selection of automotive tempered glass products. The results demonstrated the ability of the developed technique to measure the residual stress in these components and to detect defects incurred in the manufacturing process.

L’efficacité des cellules solaires peut être améliorée en exploitant pleinement la partie UV-bleue du spectre solaire, par un mécanisme de conversion de fréquence de type down-conversion. Ce processus utilisant des transferts d’énergie entre ions de terre rare (TR) ou métal de transition 3d (paires TR3+/Yb3+ avec TR = Pr, Tm,… et Cr3+/Yb3+) requiert des matrices à basse énergie de phonon pour réduire les relaxations non radiatives.Jusqu’à présent, les matériaux étudiés sont principalement sous forme de poudre polycristalline, ce qui limite leur utilisation à cause de la diffusion, ou de monocristaux dont le coût de fabrication est élevé.Dans le cadre de cette thèse, les verres fluorés à base de fluorozirconate ZLAG (ZrF4-LaF3-AlF3-GaF3) et ZBLA (ZrF4-BaF2-LaF3-AlF3) ont été préparés par la technique de fusion-coulée. Ces derniers sont adaptés du fait de leurs propriétés intrinsèques de transparence et de leur faible énergie de phonon. Les matériaux obtenus ont ensuite été caractérisés par, analyse thermique, diffraction des rayons X, microscopie électronique à transmission et luminescence.Des études par dynamique moléculaire et fluorescence par affinement de raies ont été effectuées sur la matrice ZLAG afin de suivre les modifications structurales lors du passage du verre à la vitrocéramique.La luminescence de l’ion Yb3+ a été observée dans l’infra-rouge à 980 nm sous excitation bleue dans toutes les séries étudiées, signature d’un transfert d’énergie. ans le verre ZLAG, l’efficacité atteint 92% pour le transfert d’énergie Pr3+ → Yb3+ et 65% pour le transfert d’énergie Tm3+ → Yb3+. L’efficacité est plus faible dans le verre ZBLA et la vitrocéramisation du verre ZLAG n’améliore pas les performances. / The efficiency of solar cells can be improved by fully exploiting the UV-blue portion of the solar spectrum, through a frequency converting mechanism of type downconversion. This process using energy transfer between rare earth ions (RE) or 3d transition metal (pairs RE3+/Yb3+ with TR = Pr, Tm,… and Cr3+/Yb3+) requires a matrix with low phonon energy to reduce non radiative relaxation.So far, the studied materials are mainly in the form of polycristalline powder, which limits their use due to diffusion or single crystals which manufacturing cost is high.As part of this thesis, fluoride glasses based on fluorozirconate ZLAG (ZrF4-LaF3-AlF3-GaF3) and ZBLA (ZrF4-LaF2-LaF3-AlF3) have been prepared by the melting-casting technique. These are suitable because of their intrinsic properties of transparency and low phonon energy. The resulting materials were then characterized by thermal analysis, X-ray diffraction, transmission electron microscopy and luminescence.Molecular Dynamics simulation and Fluorescence line narrowing of ZLAG matrix have been performed in order to investigate the structural modification during the transformation of the glass into the glass-ceramic.Luminescence of Yb3+ ion was observed in the near IR at 980 nm under blue excitation in all studied series, which is the signature of energy transfer. In the ZLAG glass, the efficiency reaches 92% for Pr3+ → Yb3+ energy transfer and 65% for Tm3+ → Yb3+ energy transfer. The efficiency is lower in the ZBLA glass and the ZLAG ceramisation does not improve the performances.