28 W Solar-pumped laser with a grooved Nd:YAG rod

We demonstrate a solar pumped laser with a grooved Nd:YAG rod. A Fresnel lens with a surface of 1.03 m2 is used as the primary solar light concentrator. A copper conical cavity with a water tube lens is used as the secondary concentrator, 28 W output power is obtained, corresponding to an optical-optical efficiency of laser output power with respect to focused solar power of 6.7% and a slope efficiency of 9.4%. The performances of the grooved rod are compared with a normal Nd:YAG rod usually used for flash light pumping in our solar pumped setup. Both the efficiency and the beam quality with grooved rod are superior to the unpolished rod.