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 Al2O3-doped reflective color converter. The reflective converter was prepared by printing and sintering an Al2O3-doped phosphor-in-glass (PiG) film on an AlN substrate. The Al2O3-PiG film with intact crystal structure of YAG phosphor is robustly bonded on the substrate. The optical and thermal performances of Al2O3-PiG based phosphor-converted white laser diodes (pc-WLDs) were optimized with different Al2O3 contents. The pc-WLD achieves a maximum saturation threshold of 25.2 W/mm2 and a high luminous flux of 2138 lm (luminance of 1260 Mcd
$\cdot \text{m}^{-{2}}{)}$
. The working temperature of 6%-Al2O3-PiG is only 88.4°C, which is reduced by 33.5% compared with that of Al2O3-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.