Solar pumped Nd:YAG laser with Fresnel lens

Solar energy is the most abundant renewable energy among all kinds of energy sources, solar pumped laser can be the best choice in terms of the fully utilization of solar energy. The solar pumped laser with two stage sunlight concentration system is designed and constructed. A Fresnel lens with large diameter is adopted as a primary optical concentration device, and a cone type diffuse pumping chamber functions as a secondary concentrator is used to enhance the couple efficiency between the incident solar power and laser media. Output laser power is up to 2.85 W, with the use of Nd:YAG crystal as laser media, and 0.43% optical conversion efficiency is achieved. The performance of solar pumped laser is discussed by the concentration efficiency of Fresnel lens and the power distribution along the axis of laser rod in the cavity, as well as the laser characteristic. The reasons for low efficiency are discussed, and improvement approaches are presented.