Laser-Driven Dual-Ceramic Converters enabling High‐Luminance White Light

The significant expansion of the luminescent area on transparent phosphor ceramics relative to laser spot limits the laser lighting operating in transmission configuration to achieve both high luminous flux and high brightness. Herein, by introducing polymethyl methacrylate (PMMA) as a pore-forming agent during the secondary forming process and employing a secondary sintering process under an inert protective atmosphere, we successfully fabricated a dual-ceramic converter. This converter consists of an outer porous ceramic (68wt%Al 2 O 3 -(Gd 0.1 ,Y 2.90 )AG) and an inner small-sized transparent phosphor ceramic (70wt%Al 2 O 3 -(Gd 0.1 ,Y 2.89 )AG: 0.01 Ce). Benefiting from the miniaturization of the phosphor ceramic and the enhanced cavity effect and thermal conduction provided by the high-refractive-index porous ceramic, the actual luminescent area was reduced from 7.75 mm 2 to 1.73 mm 2 , achieving a luminous exitance of 1969 lm/mm 2 – a 607% enhancement over conventional phosphor ceramics – while delivering 3407.6 lm white light of 6000 K. This work establishes a universal strategy for ceramic-based color converters through microstructural engineering, resolving the critical flux-brightness trade-off in high-power solid-state lighting.