Composite structure Al₂O₃/Al₂O₃–YAG:Ce/YAG ceramics with high color spatial uniformity for white laser lighting

Composite ceramic phosphor (CCP) is a candidate light-conversion material to obtain the high-quality laser lighting source. Phosphors based on the transmissive configuration model could not simultaneously meet the requirements of angular color uniformity and high thermal stability. In this study, a novel composite structure ceramic was designed, including Al₂O₃–YAG:Ce/YAG layered ceramic with a size of 1 mm × 1 mm for lighting, and Al₂O₃ ceramic (φ = 16.0 mm) was used as the wrapping material due to its outstanding thermal stability. The prepared ceramics exhibited excellent thermal performance and no yellow ring phenomenon. Through this design, we achieved the match of the intensity distribution of the blue and yellow lights, resulting in a high angular color uniformity of 0.9 with a view angle of ±80°. All ceramics showed no luminous saturation phenomenon, even the laser power density was increased up to 47.51 W/mm². A high-brightness white-light source with a luminous flux of 618 lm, a luminous efficiency of 126 lm/W, a CCT of 6615 K, and a CRI of 69.9 was obtained in the transmissive configuration. In particular, the surface temperature of the ceramic was as low as 74.1 ℃ under a high laser radiation (47.51 W/mm²). These results indicate that Al₂O₃/Al₂O₃–YAG:Ce/YAG composite structure ceramic is a promising luminescent material in the high-power laser lighting applications.