Laser-driven Al2O3-YAG:Ce composite ceramic phosphors-a trade-off between the low Etendue requirement and thermal management

Ceramic phosphors offer extremely high brightness and are well-suited for low-etendue optical systems. However, efficient heat dissipation under high-power-density excitation remains a key challenge. In this work, the influence of Al 2 O 3 addition on the densification, photoluminescence performance, and laser-induced damage behavior of YAG:Ce ceramic phosphors is systematically investigated. The main contribution of this study is to reveal the trade-off between low etendue and effective thermal management. The results show that a suitable amount of Al 2 O 3 addition can promote grain growth and reduce porosity. Under low power density, the emission intensity is maximized at moderate Al 2 O 3 content. As the power density increases, samples with higher Al 2 O 3 content exhibit more stable emission due to enhanced thermal conductivity and improved heat dissipation. The 20 wt% sample achieves balanced performance, exhibiting a relatively small emission spot that ensures low etendue while maintaining a comparably higher damage threshold, representing a key trade-off between low etendue and efficient thermal management.