Transparent Ceramic@Sapphire Composites for High-Power Laser-Driven Lighting

Although phosphor ceramics are promising candidates for high-power laser lighting applications, their performance is seriously restricted by luminance saturation effects. This study proposes a novel transparent ceramic@sapphire composite material design, fabricated via a straightforward high-temperature sintering process, which differs from the conventional approach of incorporating high-thermal-conductivity microcrystalline grains. This kind of composite can effectively avoid luminescence grain dilution, and deliver significantly enhanced thermal conductivity (36.9 W·m^-1K^-1) alongside superior luminescence performance. This strategy demonstrates exceptional versatility across various ceramic systems, delivering luminescence improvements of 152-319% and enhancing luminance saturation thresholds by 100-233%, relative to traditional ceramic converters. Using Lu_2-xCaMg₂Si₃O₁₂: xCe³⁺@sapphire as a representative example, the optimized composite enables substantial enhancements in luminous flux (5902 lm) and luminous efficacy (148 lm W^-1) under blue laser excitation. Compared with commercial counterparts, practical applications in automotive headlights further validate the potential of this design, offering far higher luminance intensity, extended illumination distances (> 400 m), and more uniform color distribution. This study provides a scalable and universal strategy for advancing next-generation solid-state lighting.