Porous Ce:YAG ceramics with controllable microstructure for high-brightness laser lighting

In order to meet the increasing demand for high-power laser diode lighting and displays, phosphor converters with high-brightness and high-directionality ought to be constructed to enhance the luminance and luminous efficacy. However, the pores formed during the sintering of phosphor ceramics affect the scattering effect and directionality of light. Therefore, porosity optimization and pore size regulation need to be explored. In this work, a series of Ce:YAG ceramics with various porosities and pore sizes were prepared. The influences of porosity and pore size on the microstructure, light confinement ability, and optical properties of Ce:YAG ceramics were studied. The ceramic phosphor with a porosity of 10 vol.% and a pore size of 3 mu m exhibits a good spot confinement ability and shows a high luminous flux value of 3430 lm and a central luminance (1669 592 cd/m(2)) under blue laser excitation. The 10 vol.% Ce:YAG ceramic phosphor with a pore size of 5 mu m has the highest emission intensity and gives a maximum luminous efficacy of 268 lm/W and a luminous flux of 4020 lm under 30 W/mm(2) blue laser excitation. Thus, the porous Ce:YAG ceramics are expected to be a promising candidate for high-brightness laser lighting and projection applications.