Phosphor‐in‐Ceramic‐Converted Laser‐Driven Near‐Infrared Light Sources for Multiple Intelligent Spectroscopy Applications

Abstract

Ultrabright broadband near-infrared (NIR) phosphor-converted laser diode (pc-LD) as a light source is increasingly essential for improving the sensitivity and spatial resolution of intelligent NIR spectroscopy technologies. However, the performance of NIR pc-LD is greatly hindered by the low external quantum efficiency (EQE) and poor thermal resistance of phosphor materials. Herein, a highly stable phosphor-in-ceramic (PiC) film deposited on high thermal conductivity substrate, in which the NIR-emitting Ca₃MgHfGe₃O₁₂:Cr³⁺ phosphor is incorporated into a glass-crystallized Ca₃Ga₂Ge₃O₁₂ ceramic matrix, along with the formation of a new type PiC composite material with high efficiency, absorbance, and thermal conductivity, is designed and prepared. The obtained PiC exhibits an impressive EQE of 57.7%, high thermal conductivity of 17.1 W m^-1 K^-1, and the PiC wheel demonstrates a broadband NIR emission exceeding 5 W when excited by a 450 nm laser. Finally, a groundbreaking electrically driven pc-LD device based on PiC achieves 1.6 W of NIR output, enabling multiple intelligent spectroscopy applications in archaeology and night vision imaging. This work paves the way for advancing broadband NIR light sources in a diverse range of photonic applications.