Fig. 1. (a) Schematic of the experimental setup for a CW laser irradiation system. (b) Thresholds of Er:CaF₂ crystals with different doping concentrations under CW laser irradiation at 976 nm.

Fig. 2. SEM images of typical damage morphology. (a) 1% Er:CaF₂ and (b) 2% Er:CaF₂ top views of the damage region resulting from CW laser irradiation, respectively. (c), (d) Magnified images of the rectangular region.

Fig. 3. Relationship between the maximum temperature and pump power at the incidence surface of the (a) 1% Er:CaF₂ and (b) 2% Er:CaF₂. The temperature field at the incidence surface of (c) 1% Er:CaF₂ and (d) 2% Er:CaF₂, under a pump power of 8 W.

Fig. 4. Temperature profiles in the x-axis direction of the incidence surface for 1% and 2% Er:CaF₂ for pump power from 4.17 to 16.50 W using a three-dimensional finite-element simulation model.

Fig. 5. (a) Schematic of crystal fracturing under tensile stress. Stress fields of (b) 1% Er:CaF₂ and (c) 2% Er:CaF₂ crystals as damage occurs, calculated with a three-dimensional finite-element coupled thermodynamic model.