THERMALLY ROBUST COMPOSITE PHOSPHOR CERAMIC MAKES SOLID STATE LASER LIGHTING COME TRUE

Solid state laser lighting is a newly emerging technology that combines a blue laser diode (LD) with a yellow-emitting phosphor converter to generate high-brightness white light. Due to high flux irradiation as well as thermal attacks from the incident laser, this technology draws a demanding requirement on the thermal performance of the phosphor converter. In this work, we design a Al2O3-YAG:Ce composite ceramic with a unique microstructure, where yellow-emitting YAG:Ce particles are embedded in a non-luminescent Al2O3 matrix. The composite ceramic exhibits a high thermal conductivity of 18.5 Wm(-1)K(-1) and a remarkable improvement in thermal stability (15% improvement at 300 degrees C). When irradiated under a high power density of 5000 Wcm(-2), the output luminous flux increases linearly as the incident current increases from 0.4 to 1.6 A, validating its superior reliability in high power solid state laser lighting.