5.04% system slope efficiency solar-pumped Nd:YAG laser by a heliostat–parabolic mirror system

We demonstrated a solar-pumped laser with a heliostat–parabolic mirror system. A designed conical pump cavity with a water-filled quartz tube lens was used to couple efficiently the concentrated solar radiation from the focal zone of the primary concentrator into a 5.5-mm-diameter, 95-mm-length grooved Nd:YAG crystal rod within a gold-plated conical pump cavity. For 1.0-m2 effective solar radiation collection area, 20.1-W continuous-wave (CW) output laser power was obtained, corresponding to a total system slope efficiency of 5.04%. This value was 1.31 times higher than the previous with the same solar facility. For 1.5-m2 effective collection area, 34.6-W CW output laser power was achieved at the total system slope efficiency of 4.51%. A strong dependency of laser power on laser rod mounting position was also found.