Ten W Class of Stable Solar-Pumped Laser Using a Cone-Shaped Solar Cavity and 0.7 m²-Fresnel Lens

Solar energy is gaining attention as a major renewable resource for realizing a sustainable society. Solar-pumped lasers, which convert sunlight directly into coherent light, offer a novel method of energy utilization. Previously, we developed a solar-pumped laser system using a 4 m 2 Fresnel lens and achieved high efficiency; however, we encountered challenges such as thermal damage to the laser medium and instability due to the elevation changes of the Sun. In this study, we designed a compact solar-pumped laser system using a 0.7 m 2 -Fresnel lens and cone-shaped solar cavity. We introduced a mechanically stabilized mounting structure to address the instability of the laser head caused by the motion of the Sun. We achieved stable laser oscillation for 120 s with a peak output that exceeded 10 W and maintained over 80% of that power throughout the duration. This system demonstrated improved stability, compactness, and usability in outdoor conditions, thereby representing a significant advancement in solar-pumped laser technology and its practical deployment.