A great advantage of glasses is that we can easily modify their optical properties by acting on their chemical composition. The mixture of the basic components of glass, such as silica (SiO2), with rare earths, such as erbium (Er), terbium (Tb), ytterbium (Yb) or europium (Eu), has a large number of applications in photonics.
In this way, it is possible to manufacture glasses that emit light in the dark, thanks to photoluminescence, a phenomenon in which bodies absorb light with a determined energy (for example, ultraviolet radiation) and emits it with inferior energy (in this case, visible light). By changing the quantity and the rare earth elements, photoluminescent glasses which emit different coloured light are obtained. Moreover, the introduction of nanoparticles makes it possible to obtain photoluminescent glasses, with improved thermal and mechanical properties, which have a wide range of applications in laser devices, screens and photovoltaic cells.