Kang Jian, Liu Xuanchu, Liu Zitong, Sun Bingheng, Li Yang, Strekand Wieslaw, Tomala Robert Andrzej, Stefanski Mariusz, Zhang Le, Chen Hao
Opt Lett. 2024 Oct 15;49(20):5933-5936. doi: 10.1364/OL.538961.
Ceramic phosphors have high thermal conductivity and high thermal stability, showing great potential for use in laser lighting. However, it is difficult to further improve the forward efficiency in transmissive mode because of the arbitrarily emitting ceramic phosphors and light loss by secondary optical components. Here, an effective design of rod-shaped LuAG:Ce transparent ceramics was proposed, and the silicone encapsulated ceramic-based devices could operate stably under 3.5 W laser excitation, possessing a luminous efficiency of 150-180 lm/W, far exceeding the level of existing commercial transmissive mode. Besides, because of the gradual absorption of blue light and the gradient distribution of heat, the rod-shaped LuAG:Ce transparent ceramics could bear a power density of 46 W/mm without luminous saturation, and the thermal-induced luminous degradation only accounted for 7% under a 15 min operation. The ceramic-based laser lighting sources with low divergence angle (∼4°) and uniform spatial distribution were obtained. Our optimized transparent ceramic rod and encapsulation scheme provided a solution to improve the efficiency of a transmissive mode for laser lighting.
陶瓷荧光粉具有高导热性和高热稳定性，在激光照明领域展现出巨大的应用潜力。然而，由于陶瓷荧光粉的出光方向任意以及二次光学元件造成的光损失，透射模式下的正向效率难以进一步提高。在此，我们提出了一种有效的棒状LuAG:Ce透明陶瓷设计方案，基于该陶瓷封装硅胶的器件在3.5 W激光激发下能够稳定运行，发光效率为150 - 180 lm/W，远超现有商用透射模式的水平。此外，由于蓝光的逐渐吸收以及热量的梯度分布，棒状LuAG:Ce透明陶瓷能够承受46 W/mm的功率密度而不会出现发光饱和现象，并且在15分钟的运行时间内热致发光退化仅占7%。我们获得了具有低发散角（约4°）和均匀空间分布的基于陶瓷的激光照明光源。我们优化后的透明陶瓷棒和封装方案为提高激光照明透射模式的效率提供了解决方案。
