Phosphor-converted warm white laser diodes with high saturation threshold through a PiGF-dual sapphire converter

Abstract

Phosphor-converted warm white laser diodes (LDs) with high luminescence saturation threshold through blue LD chips and a phosphor in a glass-dual sapphire (PiGF-D) converter were proposed for high color rendering laser lighting. The red-emitting PiGF-D was prepared by sintering a CaAlSiN₃:Eu²⁺ (CASN) PiGF between dual sapphire substrates via thermocompression bonding. Benefitting from efficient double-sided thermal channels, the R-PiGF-D converter enables a record saturation threshold of 34.5 W mm⁻², which is 3.5 times that of the traditional R-PiGF converter (9.8 W mm⁻²). By mixing the yellow and red phosphor glass composites, the Y/R-PiGF-D based white LD achieves a warm white light with an excellent color rendering index (CRI) of 87.5 and a high luminous flux of 2010 lm@31.7 W mm⁻². The proposed PiGF-D based white LDs may be ideal laser light sources with high light quality and superior luminance for high-brightness lighting.