Al2O3-YAG:Ce/YAG composite ceramic phosphor in a transmissive configuration for high-brightness laser-driven lighting

Abstract

High-power, high-brightness laser lighting promotes new requirements for light-conversion materials, such as high thermal conductivity, high saturation threshold and compact encapsulation. In this paper, we designed and fabricated a novel composite structure ceramic including a 1.0 × 1.0 mm2 Al2O3-YAG:Ce ceramic and a φ=16.0 mm transparent YAG ceramic for the transmissive configuration in laser lighting. When pumped by blue laser from 0∼60 W mm2, all the samples exhibited no luminous saturation phenomenon, and the 10.0 wt.%Al2O3-YAG:Ce/YAG composite ceramic with the thickness of 0.3 mm maintained white light with a luminous efficacy over 200 lm/W. Moreover, a maximal luminous flux over 1000 lm, a correlated color temperature (CCT) of 5471 K, and an operating temperature as low as 92.3 °C were obtained under the excitation power density as high as 60 W/mm2. The configuration that Al2O3-YAG:Ce encapsulated by YAG reflects an excellent optical and thermal properties by using transparent and highly thermally conductive YAG materials. These results indicate that Al2O3-YAG:Ce/ YAG composite ceramic phosphor is a promising candidate in transmissive configuration for automotive lighting and laser searchlight.