Photonics Glass-ceramics
Résumé
Transparent glass ceramic are nanocomposite systems that exhibit specific mor-phologic, structural and spectroscopic properties allowing to develop interesting new physical concepts, for instance the mechanism related to the high observed transparency and to the peculiar thermal properties, as well as novel photonic devices based on the enhancement of the luminescence and photons management. At the state of art, the fabrication techniques based on bottom-up and top-down approaches appear to be viable although a specific effort is required to achieve the necessary reliability and reproducibility of the preparation protocols. In particular, the dependence of the final product on the specific parent glass and on the employed synthesis still remain an important task of the research in material science. Looking to application, the enhanced spectroscopic properties typical of transparent glass ceramic activated by rare earth ions, in respect to those of the amorphous structures constitute an important point for the development of integrated optics devices, including optical amplifiers, monolithic waveguide laser, novel sensors, coating of spherical microresonators, and up and down converters for solar energy exploitation. The more important point to be resolved now is to develop a specific protocol for the patterning of the glass-ceramic avoiding worsening of the optical properties induced, for instance by the reactive ion etching process. In the case of oxide glasses exploitation of photorefractive properties is recently attempted with promising preliminary results. The excellent flexibility of the physical vapor deposition technique could be employed to deposit the material into suitable channels and layouts previously fabricated on the substrate. This lecture presents a short overview of the state of art in transparent glass ceramics focusing the discussion on photonics application and evidences the capital scientific and technological interest of this kind of two-phase materials, which require and allow common multidisciplinary research involving scientists coming from a large spectrum of disciplines.