High-Particle-Density YAG:Ce Phosphor Coating for High Power Laser Lighting

Inorganic Ce doped yttrium aluminum garnet (YAG:Ce) fluorescent plates based on various manufacturing methods have been studied in recent years for laser lighting systems. A laser lighting optical system is designed to generate high central intensity beam, and light spreading effect for both YAG single crystal and YAG/Al2O3 composite is investigated. YAG single crystal and YAG/Al2O3 composite lose 50.8% and 25.9% of their light power from central pumping area, respectively, resulting in proportional decrease in central intensity. To solve this problem, a low-cost YAG:Ce high-particle-density phosphor coating (HPD-PC) was prepared for Etendue-limited applications. With only 8.5% of light spreading, under 47.7 W/mm2 pumping power density, YAG HPD-PC emits 1880 lm with the conversion efficiency of 157 lm/W. YAG HPD-PC also could work well under power density more than 100 W/mm2.