Solar Energy, Vol.177, 440-447, 2019
Continuous oscillation of a compact solar-pumped Cr, Nd-doped YAG ceramic rod laser for more than 6.5 h tracking the sun
Remaining key challenges for solar-pumped lasers (SPLs) to be applied for terrestrial solar energy utilization are (1) improvement of energy conversion efficiency and (2) ability of continuous laser oscillation during the day time. To address the latter challenge (2), a compact SPL employing a rigid 76.2 mm caliber paraboloidal mirror and a 10 mm-long, 1 mm diameter Cr, Nd-doped YAG ceramic rod was developed to realize more stable oscillation performance by introducing rapid cooling by free/natural air convection and increased mechanical stability during wind exposure in contrast to the conventional large solar pumped lasers (SPLs) employing typically a 2 m size conversing lens or mirror. Arrays of the compact SPLs could be used for harvesting sunlight across a large area. Outdoor, solar tracking experimentation with the compact SPL yielded continuous oscillation exceeding 6.5 h, improving upon previously determined maximum continuous oscillation times of 11 min. This is an indispensable experimental step if SPLs are to be applied to terrestrial solar energy utilization.