Aligned Fiber Induced Laser‐Driven Bamboo Diffuser Enabling Highly Directional Illumination Applications

Abstract Directional optical diffusers provide customizable spatial intensity light distributions and have potential applications in next‐generation directional lighting devices. The manufacturing procedures for directional lighting devices suffer from insufficient directionality, complex manufacturing conditions, and unsustainability. Herein, bamboo is processed directly into a directional laser‐driven bamboo diffuser (LDBD) by delignification and subsequent impregnation with a polymer (poly(ethylene glycol)diacrylate and epoxy acrylate) with a mismatched refractive index. The LDBD shows a distinctly elliptical directional light distribution under laser irradiation. Then, a bright, efficient, and tunable white directional lighting from Y 3 Al 5 O 12 :Ce 3+ (YAG: Ce)‐added LDBDs is obtained by regulating the power of a 450 nm laser and YAG: Ce concentration. Optimal white lighting by the LDBD is obtained at a power of 400 mW and 1% YAG: Ce concentration. This provides standard white CIE 1931 chromaticity coordinates (0.33, 0.33), suitable correlated color temperature (5406 K), and high color rendering index (81.2%). Furthermore, the optimized bamboo diffuser exhibits satisfactory mechanical properties, as well as long‐term thermal and water resistance. Due to the unique materials design and facile fabrication strategy, LDBD shows promise for optical fiber‐guided, non‐contact, long‐distance, undersea, and other highly directional laser lighting applications.