A new report from Prof. Takashi Yabe: 100 W-class solar pumped laser for sustainable magnesium-hydrogen energy cycle, J. Appl. Phys. 104, 083104 (2008). They used a Fresnel lens (2×2 m, f=2000 mm) for collecting solar radiation, a Cr:Nd: YAG ceramic rod as gain medium, and get 80 W maximum laser power, corresponding to a 4.3% net conversion from solar light. That's really a cool result.

I always say to my colleagues that solar pumped laser is my dream research project, because then I can do experiments under sunshine instead of in a basement lab. ;)