Thermal conditions of the Er:YAG laser under stationary diode pumping

Experimental results and calculation data for the thermal conditions of the YAG:Er laser active element shaped as a flat plate under pumping by continuous radiation of a diode array (λ = 980 nm) with fiber output are presented. The thermal field and temperature in the plate optical excitation channel are measured using the thermal imaging technique. Their dependence on the pump power is studied. A comparison of calculated and experimental data allowed the determination of the heat transfer coefficient from the YAG:Er crystal to air under conditions of natural convection.