Research progress on Dy-activated crystals to realize yellow emission in one step via commercial blue LD pumping

As is well known, Dy-doped crystals are capable of exhibiting yellow emission in the range of 570–590 nm. Owing to their potential use in the fields of biomedical instruments, optical storage, precision measurements, illumination displays, Bose–Einstein condensation, etc., Dy-activated yellow luminescent crystals have attracted considerable attention. In recent years, due to the widespread use of light-emitting diodes, considerable progress has been made on InGaN/GaN-based blue laser diodes (LDs), which provide a new approach for rare-earth-ion-activated crystals to obtain yellow lasers in one step. This has become a hot topic in the scientific and technological research communities and has prompted the development of research on yellow lasers. Based on Dy-doped crystals, we first summarize the research results and progress that has been made to achieve yellow emission in one step using the blue LD pumping technology. Besides, the prospect of obtaining yellow emission from Dy-activated crystals is also presented. Finally, this review aims to help researchers to further develop Dy-activated crystals with yellow emission under the excitation of blue LDs.