Glass-Based Materials for (Bio)Photonic Applications

Glass-based materials are of interest for the engineering of photonic devices, due to their easy processing. Depending on their composition, they can be engineered with good thermal stability, excellent optical properties and high rare-earth ions solubility. The concept of laser glasses relates to the doping of a glass with rare-earth (RE) ions. These materials have been developed since 1961, when Nd ³⁺ ions were first considered for laser applications. Glasses with persistent luminescence have been also of great importance as they emit light for hours once the excitation source, responsible for charging it, is removed.[1] This persistent luminescence (PeL), also called afterglow, is a consequence of energy storage in the material during excitation, when the absorption of the excitation light leads to charge trapping at a defect site which is then followed by the spontaneous release of the trapped charge and the emission of a photon, provided that sufficient thermal energy is available. However, the afterglow is mainly obtained using UV-visible light.