Laser-driven broadband near-infrared light source with watt-level output

High-power broadband near-infrared (NIR) light sources based on laser-excited phosphors are highly desirable for photonics applications in night vision, biomedical imaging and sensing; however, the inherent energy gap law poses a great challenge for the development of efficient NIR luminescent materials. Herein we report a translucent MgO:Cr 3+ ceramic fabricated by spark plasma sintering, which exhibits a broadband NIR emission peak at 810 nm, with an external quantum efficiency of 81% and ultra-high thermal conductivity of 52 W m –1 K –1 . When pumped with a blue laser, the MgO:Cr 3+ ceramic provides an output power exceeding 6 W with a light conversion efficiency of 29%. This laser-driven broadband NIR light source makes it possible to perform NIR imaging with a spatial resolution of 6 lp mm –1 , and is a promising technology for emerging imaging applications. A transparent ceramic phosphor based on Cr 3+ -doped MgO offers a route to a powerful broadband near-infrared light source.