Laser-Driven White Light Source with High Luminescence Saturation Through Reflective Color Converter

In this letter, a laser-driven white light source with high luminescence saturation was fabricated by combining blue laser chips and an Al 2 O 3 -doped reflective color converter. The reflective converter was prepared by printing and sintering an Al 2 O 3 -doped phosphor-in-glass (PiG) film on an AlN substrate. The Al 2 O 3 -PiG film with intact crystal structure of YAG phosphor is robustly bonded on the substrate. The optical and thermal performances of Al 2 O 3 -PiG based phosphor-converted white laser diodes (pc-WLDs) were optimized with different Al 2 O 3 contents. The pc-WLD achieves a maximum saturation threshold of 25.2 W/mm 2 and a high luminous flux of 2138 lm (luminance of 1260 Mcd·m -2 ). The working temperature of 6%-Al 2 O 3 -PiG is only 88.4°C, which is reduced by 33.5% compared with that of Al 2 O 3 -free-PiG. The fabricated small pc-WLD device has high-luminance white light, excellent collimation, and long illumination distance, which is a promising light source for high-brightness lighting.