Highly Stable Phosphor in Glass‐Ceramic Film Composites for Laser‐Driven Lighting Sources

ABSTRACT Laser‐driven phosphor‐converted white‐light (pc‐wLD) sources require color converters that simultaneously deliver high luminescence quality, excellent spatial color uniformity, and robust thermal stability. Here, a highly stable phosphor in glass‐ceramic film (PiGCF) is developed by embedding (Lu, Y, Gd) 3 (Al, Ga) 5 O 12 : Ce 3+ phosphors into a lithium silicate glass‐ceramic on sapphire substrates. The interlocked microcrystalline network serves as both an efficient thermal‐conduction framework and an effective light‐scattering medium, ensuring a low internal quantum‐efficiency loss of only 4.6%, a high thermal conductivity of 23 W m −1 K −1 and outstanding spatial color uniformity. For instance, the YAG:Ce PiGCF achieves a high incident laser power density (LPD) of 22 W opt mm −2 and a lumen density of 2022 lm mm −2 . To enable practical integration, a dedicated packaging strategy based on a copper‐cladding structure (CCS) with multi‐channel thermal pathways was implemented. Meanwhile, a laser‐driven layered CASN‐PiG/YAGG PiGCF@CCS configuration enables warm‐white emission with a high color rendering index (CRI) of 92.9 and a low correlated color temperature (CCT) of 3450 K, demonstrating significant potential for applications in medical endoscopic illumination. Overall, this study underscores the considerable promise of glass‐ceramic matrix architectures for next‐generation laser‐driven lighting technologies.