Solar-pumped Cr:Nd:YAG ceramic laser with 6.7% slope efficiency

We report here a significant progress in solar laser slope efficiency by end-side-pumping a 4.5 mm diameter, 35 mm length Cr:Nd:YAG ceramic rod with a 1.0 m2 effective collection area heliostat-parabolic mirror solar energy concentration system. A novel fused silica liquid light guide lens with unique water cooling approach was used to efficiently couple the concentrated solar radiations from the focal zone of a parabolic mirror into the laser rod within a conical pumping cavity. 32.5 W continuous-wave 1064 nm solar laser power was measured, corresponding to 6.7% slope efficiency, being 1.28 times more than the previous record. The highest solar laser collection efficiency of 32.5 W/m2 was also achieved.