High-Luminance White-Light Point Source Using Ce,Sm : YAG Double-Clad Crystal Fiber

Ce and Sm ions codoped yttrium aluminum garnet (Ce,Sm : YAG) double-clad crystal fibers (DCFs) were successfully fabricated using the codrawing laser-heated pedestal growth method. At a pump wavelength of 446 nm, white-light point source was produced from a 10--core DCF. The amplified spontaneous emissions and the residual pump resulted in a directional high brightness point source. A luminance of 4.5 × 10⁹ cd/m² was generated. The luminous flux of the point white light was 6.2 lm. When coupled to a 200-core multimode fiber, the output power and coupling efficiency were 4.8 mW and 36.8%, respectively. Point white-light sources are useful for biomedical endoscopic application and long-range directive illumination. The generated broadband yellow emission can also be served as the light source for optical coherence tomography system. Using the 91-nm yellow emission, an axial resolution of 1.5-optical coherence tomography can be achieved for ultrahigh-resolution ocular and industrial applications.