Efficient 38.8 W/m2 solar pumped laser with a Ce:Nd:YAG crystal and a Fresnel lens.

Herein, we report a significant improvement in solar-pumped laser collection efficiency based on end-side pumping a 6-mm-diameter 95-mm-length Ce:Nd:YAG/YAG grooved bonded crystal rod. A Fresnel lens, quartz cooling-water tube, and gold-plated conical cavity constituted the solar-energy collection and concentration system, which was designed to maximum pump light absorption and minimize thermal effects in the Ce:Nd:YAG laser medium. To the best of our knowledge, this is the first time that a Ce:Nd:YAG crystal has been pumped by a Fresnel-lens solar-energy collection and concentration system. The 0.69-m2 effective solar-collection area produced 26.93 W of continuous-wave laser power, corresponding to 6.33% slope efficiency. The collection efficiency (38.8 W/m2) was 1.21 times higher than the highest previously reported value for Fresnel-lens solar collection, and is a record for single-beam solar-pumped lasers.