Thermal Analysis of HO : CaF2 Crystal Pumped by 1.9 μm Laser Diode

In this paper, we establish a three-dimensional heat conduction and thermal stress model of a bulk crystal. Based on planar strain assumption of solid-state lasers, we study the thermal conduction and thermal stress of the bulk Ho : CaF₂ laser-medium end-pumped by the Gaussian beam. We establish a thermal model of the plate crystal with complex boundary conditions and discuss the effect of pump energy and pump beam waist radius on the thermal performance of Ho : CaF₂ crystals in details. Out results show that, as the pump power increases, the thermal effect of Ho :CaF₂ crystal increased with the decrease of the pump-spot radius, and the thermal effect of the crystal increases with increase in the pump power. Furthermore, the absolute value of the shear stress of crystals is far smaller than the absolute value of the corresponding normal stress, and the absolute values of the normal stress and shear stress of small size crystals are greater than those of large size crystals.