A super-high brightness and excellent colour quality laser-driven white light source enables miniaturized endoscopy.

A laser-driven white light source promises intrinsic advantages for miniaturized endoscopic illumination. However, it remains a great challenge to simultaneously achieve high brightness and excellent colour rendition due to the shortage of highly efficient and thermally robust red-emitting laser phosphor converters. Here, we designed CaAlSiN:Eu@Al (CASN@Al) converters with neglectable efficiency loss by tightly bonding all-inorganic phosphor films on an aluminium substrate.