Unique Design Strategy for Laser-Driven Color Converters Enabling Superhigh-Luminance and High-Directionality White Light

Robust ceramic color converters withstanding strong laser irradiations have recently drawn great attention for laser-driven white lighting. However, the local emission within the incident laser spot usually expands to the whole surface area of the ceramics, which definitely makes it hard to achieve white light with high luminance and high directionality. Herein, a new strategy is proposed to solve the problem by elaborately introducing uniform spherical pores (diameter of ≈2 µm) into the phosphor ceramics with controlled contents from 8 to 24.6 vol%. The well-distributed pores, acting as light scattering centers, enable reduction of the luminescent spot size greatly but without any losses in conversion efficiency. By using the high-scattering ceramic color converters with 15% porosity, the light spot diameter is decreased by 46% and the central illuminance is increased by 156%. Moreover, laser-driven white light with an enhanced beam directionality and uniformity is also achieved. A superhigh luminous flux of 7199 lm is realized by using this promising color converter in a rotary mode. The designed high-scattering ceramics with controllable microstructures show great potential for use in extra-high luminance laser-driven lighting and projection.