Solar-pumped TEM₀₀ mode laser simple design with a grooved Nd:YAG rod

A simple high-brightness TEM₀₀ mode solar laser design with a grooved Nd:YAG rod pumped through a heliostat-parabolic mirror system is proposed here. A fused silica semi-cylindrical lens was combined with a 2V-shaped pumping cavity to provide efficient side-pumping along the grooved 1.0at.% Nd:YAG rod. Optimum pumping and laser beam parameters were found through ZEMAX and LASCAD numerical analysis. The proposed scheme offered a circularly symmetric and uniform absorption profile. Maximum TEM₀₀ mode solar laser power of 25.5W was numerically achieved with a 3.5mm diameter grooved rod, corresponding to 8.5W/m² collection efficiency. 17.1W laser beam brightness figure of merit was attained, being 4.3 times more than the previous record with TEM₀₀ mode Nd:YAG solar laser, and 10,000 times higher than last year's result with a large grooved Nd:YAG rod. To validate the proposed pumping scheme, a solar laser prototype was built and firstly tested with a small-scale heliostat-parabolic mirror system of Universidade NOVA de Lisboa, producing 4.0W continuous-wave TEM₀₀ mode solar laser power at 3.6W/m² collection efficiency and 3.0W laser beam figure of merit.