Sol-gel-derived transparent glass-ceramics for photonics

Photonic glass-ceramics are two-phase materials constituted by nanometer sized crystals, passive or activated by luminescent species, embedded in a glass matrix. Among the different techniques used to fabricate transparent glass ceramics the sol-gel route is highly appreciated because it allows to explore different compositions and develop novel functionalities. By engineering glass-ceramics chemistry, nature, or volume fractions of crystalline and amorphous phases, several interesting properties can be achieved and tailored so that the sol-gel technique appears one of the most versatile processes for the fabrication of photonic systems. The aim of the present paper is to give a brief state of the art and some significant examples of systems developed, even in our research network, during the last ten years of activity, in order to highlights the reliability and versatility of sol-gel -derived glass-ceramics for photonics application. With this aim, the main topics discussed here deal with: (i) transparent rare-earth-activated SiO2–SnO2 glass-ceramics; (ii) mechanical properties of glass ceramics coatings.