Solar-pumped Nd:YAG laser with 31.5 W/m2 multimode and 7.9 W/m2 TEM00-mode collection efficiencies

•Most efficient multimode Nd: YAG solar laser with 31.5 W/m2 collection efficiency.•Most efficient TEM00-mode Nd: YAG solar laser with 7.9 W/m2 collection efficiency.•First highly efficient solar laser emission from a stationary solar laser head within a laboratory.

We report here significant progresses in both multimode and TEM00-mode solar-pumped laser collection efficiencies by end-side-pumping a 4.0 mm diameter 35 mm length Nd: YAG single-crystal rod with a heliostat-parabolic mirror solar energy concentration system. An aspheric fused silica lens was used to couple the concentrated solar radiations from the focal zone of a 1.4 m effective diameter parabolic mirror into the laser rod within a conical pumping cavity. 37.2 W continuous-wave multimode solar laser power was measured, corresponding to 31.5 W/m2 multimode laser collection efficiency and 8.9% slope efficiency. 9.3 W continuous-wave TEM00-mode (M2 ≤1.2) solar laser power and consequently 7.9 W/m2 fundamental-mode laser collection efficiency was registered, doubling the previous record.