Transition metals as optically active dopants in glass-ceramics

Over the past few decades, glass-ceramics doped with transition metals have become promising materials for the development of active and passive optical functional devices, including a wide variety of commercial applications due to their unique properties. In this Perspective paper, the intrinsic advantages of these composite materials are outlined, and we provide an overview of recent and on-going progress and state-of-the-art knowledge of the main applications: broadband amplifiers, tunable lasers, long persistent phosphors, noninvasive optical temperature sensors, saturable absorbers, high IR emitters, and thermal shock-resistant color filters. Finally, today's challenges and future prospects are exposed to provide guidelines for future research.