25 W/m(2) collection efficiency solar-pumped Nd:YAG laser by a heliostat-parabolic mirror system

摘要

A large aspheric fused silica lens was used to couple efficiently the concentrated solar radiation from the focal zone of a 1.5-m-diameter primary concentrator into a 4-mm-diameter, 35-mm-long Nd:YAG single-crystal rod within a conical pump cavity. Continuous-wave laser power of 29.3 W was measured, attaining 25.0 W/m(2) solar laser collection efficiency, corresponding to a 19% increase over the previous record. Its laser beam figure of merit-the ratio between laser power and the product of M-x(2), M-y(2) beam quality factors-of 0.01 W is 1.6 times higher than that of a direct tracking solar laser with 30 W/m(2) collection efficiency. A strong dependency of solar laser power on laser resonator cavity length was found. (C) 2016 Optical Society of America