Thermal analysis of a high-power cw solar-pumped laser under development as a magnesium energy cycle driver has
been conducted experimentally and analytically. The laser system is equipped with a Fresnel lens and a cone-shaped
secondary mirror chamber (SMC). The SMC realizes a hybrid-pumping scheme combining axial- and side-pumping
configurations to enhance solar light absorption to a rod-shaped laser medium. A non-uniform temperature profile was
obtained during experiments due to combination of volumetric heating and surface cooling, which leads to a nonuniform
variation of index of refraction in the laser medium. The thermal lensing and thermal stress-induced
birefringence are analyzed.