Solar side-pumped Nd : YAG single crystal fiber laser

We propose a kind of side pumping configuration with a three-stage solar concentrator to improve the output power of solar-pumped single crystal fiber (SCF) laser. The primary concentrator system consists of 10 off-axis parabolic mirrors, and the secondary and third-stage concentrators are 10 two-dimensional composite parabolic concentrators (2D-CPCs) and the 2V-shaped reflectors, respectively. Sunlight is reflected multiple times in the 2V-shaped reflector and is absorbed by a Nd : YAG SCF (∅1 mm × 80 mm) for laser oscillation. Ray tracing demonstrates that the solar power absorbed by the SCF reaches 132.7 W. We solve the rate equation and transmission equation, the obtained results show that the laser output power, slope efficiency, and solar-laser conversation efficiency are 46.3 W, 38.9%, and 1.5%, respectively. The concentrator system can provide new ideas for solar-pumped SCF lasers.