Design and thermal evaluation of a 97 W solar-pumped Ce:Nd:YAG laser with 4.49% solar-to-laser conversion efficiency

A highly efficient 100 W-level solar-pumped Ce:Nd:YAG laser system is reported, achieved using a Fresnel lens with great central focusing capability. The lens, with an effective area of 2.7 m², was utilized for end-side pumping a Ce:Nd:YAG crystal rod with a diameter of 7 mm and a length of 90 mm. At a solar irradiance of 802 W/m², the system produced an output power of 97.28 W, with a collection efficiency of 36.03 W/m² and a solar-to-laser conversion efficiency of 4.49%. This power output is 1.09 times the previous record for Ce:Nd:YAG systems and approaches the highest conversion efficiency of single rod systems using a parabolic mirror, with 8.69 times higher power. Experiments and simulations confirmed that the high-concentration end of the crystal rod is more prone to fracturing when used as the incident end during high-power end-side pumping, especially in systems where incident light is more concentrated in the central region.