This paper presents a comprehensive analysis of white light generation and the associated aging dynamics using high-power blue laser diodes (LDs) combined with transmissive single crystal remote YAG phosphors. By systematically varying input currents (ranging from 0.6 A to 3 A) and phosphor thicknesses (250 μm and 500 μm), this study elucidates the optical and electrical characteristics of LD-phosphor systems under diverse operating conditions. The results highlight the system’s potential for stable and efficient white light generation, making it suitable for high-power lighting applications. Experimental setups included both single LDs and a 4 × 2 LD array. For the single LD, a peak optical output of 4.16 W was achieved at 3 A, corresponding to an initial luminous flux of approximately 700 Lm and a correlated color temperature (CCT) of 4653 K, with minimal color temperature shift observed during a 60 min aging process. The 4 × 2 LD array demonstrated consistent white light output across varying phosphor thicknesses, with maximum luminous fluxes of 1857 Lm at 1.4 A and 2622 Lm at 1.6 A for phosphor thicknesses of 250 μm and 500 μm, respectively. Importantly, the phosphor exhibited excellent thermal stability throughout the aging process, with the CCT maintained within a range of 4600 K to 5500 K. These findings underscore the reliability and applicability of LD-based white light systems in demanding high-power lighting environments, offering a promising alternative to conventional light sources for automotive, industrial, and specialized lighting applications.

In this paper, a large-capacity white light source module using a high-power blue laser diode and a reflective spaced phosphor was designed. The reflective spacing phosphor ensured thermal stability. The proposed white light module is a reflective phosphor structure with a bi-directional optical system based on a rhombus prism lens. The rhombus prism optical system can greatly narrow the blue laser beam width and a long-wavelength band-pass filter of 500 $\mathrm{nm}$ or more is applied to change the movement path of the laser beam and transmit white light excited by the phosphor. A dichroic filter was applied to the fold mirror part and a planar convex lens was designed to focus the blue laser beam so that the phosphor was irradiated. Finally, a high-power white light source is obtained from the pre-optics unit to which the dichroic filter is applied. In order to use the proposed white light source as a searchlight, a divergence angle of 4° or less is required. For this implementation, a large-area collimating lens combining an aspheric condensing lens and an achromatic lens was applied. It was confirmed that the divergence angle of 4 degrees or less was satisfied at the focal length (FL) of 38.5 to 42.5 mm of the optical lens of the laser white light module emitter and the collimating optical system.

This study experimentally evaluates two Ce³⁺ single-crystal phosphor configurations and implements a laser-diode-driven remote-phosphor (LDRP) module for high-intensity searchlight applications. Phosphor plates with thicknesses of 0.71 and 1.24 mm were characterized under excitation from a 450 ± 5 nm blue laser-diode array. Photometric, colorimetric, and 20-min temporal measurements were performed at selected drive currents between 1.2 and 2.2 A. At 2.0 A, the 0.71 mm phosphor produced approximately 12.5% higher luminous flux than the 1.24 mm phosphor, mainly because its shorter optical path increased the contribution of residual blue light. The 1.24 mm phosphor exhibited smaller current-dependent chromaticity variation. The 0.71 mm phosphor maintained stable output up to 2.0 A but fractured shortly after the application of 2.2 A. In contrast, the 1.24 mm phosphor remained stable at 2.2 A without measurable flux degradation during the 20-min measurement interval. The 1.24 mm phosphor was therefore employed in the integrated module. The module was characterized at 11.84 V and 2.202 A, corresponding to an electrical input power of 26.07 W. It produced near-white emission with chromaticity coordinates of (0.3123, 0.3434). Far-field goniophotometry measured a peak luminous intensity of 280 kcd with an FWHM beam divergence of 2.5°. The estimated on-axis illuminance was 1.12 lx at 500 m under clear atmospheric conditions; this value represents a theoretical propagation estimate rather than a direct field measurement. These results demonstrate the measured trade-off between luminous output and chromaticity stability, together with the different luminous-flux behaviors observed for the two evaluated configurations during the 20-min measurement interval.