The temperature profile within Er 3+: Yb 3+: LuAl 3 (BO 3 ) 4 crystal: Insights uncovered by a combined theoretical and experimental study

This work reports a measured temperature profile along the pump light beam inside the Er 3 + :Yb 3 + : LuAl 3 (BO 3 ) 4 crystal and the simulated ones. The temperature profile featured by a high and asymmetrical peak structure shows rather localized nature with respect to its transversal distribution. By scrutinous examination of the discrepancies between the experimental and simulated ones, a) a heat deposition mechanism elucidating the steady state of local heat generations and various heat transfers was suggested; b) a three -beam of lights model together with a formula for analyzing the fractional thermal load was developed, which leads to a good agreement between the simulated and experimental temperature profiles. The new formula provides a more transparent tool in physics to evaluate the various energy losses; The model can easily be adapted to solve the thermal problem in a laser medium, in particular when a medium show unignorable absorption effect for the laser signal.