Laser-driven luminescent ceramic-converted near-infrared II light source for advanced imaging and detection techniques

Near-infrared (NIR) light sources have revolutionized multiple fields including biomedical imaging, material analysis, and security screening through their non-destructive detection capabilities. While traditional incandescent sources suffer from low efficiency and bulkiness, phosphor-converted LEDs (pc-LEDs) initially emerged as compact alternatives. However, three fundamental limitations persist: inherent LED efficiency droop, phosphor thermal degradation and poor thermal conductivity (~0.5 W·m ^-1 ·K ^-1 ) of organic binders. These challenges have propelled the development of near-infrared luminescent ceramic-converted laser diodes (NIR lc-LDs), which combine laser diode excitation with ceramic converters offering superior thermal stability and high-power endurance.

In this work, MgO:Ni ²⁺ ,Cr ³⁺ luminescent ceramics based on non-equivalent cation substitution strategy and high temperature ceramic sintering method was developed. More importantly, non-equivalent cation substitution of Mg ²⁺ by co-doping with Cr ³⁺ results in a high lattice distortion in [NiO ₆ ] octahedral, which breaks the parity-forbidden 3d-3d transition of Ni ²⁺ and consequently improves its luminescence efficiency. At the same time, resonant energy transfer from Cr ³⁺ to Ni ²⁺ further improves the luminescence efficiency of Ni ²⁺ . The resultant MgO:N ²⁺ ,Cr ³⁺ ceramics achieve unprecedented 39.69% EQE with NIR-II emissions at 1330 nm, high thermal conductivity of 31.28 W·m ^-1 ·K ^-1 , and excellent anti-luminescence thermal quenching of 92.11%@478K. Implemented in laser-driven devices, these ceramics enable record 214 mW output power under 21.43 W/mm ² blue laser excitation. Benefitting from the fabricated NIR-II lc-LDs based on translucent MgO:Ni ²⁺ ,Cr ³⁺ ceramics, we successfully demonstrated non-destructive imaging capabilities with spatial resolution of 5.29 lp/mm and 0.97 contrast ratio. This work provides rational design of Ni ²⁺ -activated NIR-II luminescent ceramics for next-generation laser-driven NIR-II lighting source, thereby meeting the growing demands in non-destructive detection and imaging applications.

10.1038/s41377-025-01953-4

Laser-driven luminescent ceramic-converted near-infrared II light source for advanced imaging and detection techniques