Thermo-mechanical properties and laser-induced damage behaviors in NYCF and NYSF crystals with different orientations

Nd,Y:CaF₂ (NYCF) and Nd,Y:SrF₂ (NYSF) crystals are excellent types of laser gain media owing to their enhanced absorption-emission cross sections and fluorescence lifetimes, and high thermal conductivity. In this study, the laser damage behaviors of crystals with different orientations under a 1064 nm nanosecond laser are analyzed through investigation of the thermo-mechanical properties with different orientations. The results demonstrate that the superior thermal conductivity and flexural strength of NYCF crystals contribute to a higher thermal shock resistance parameter and laser-induced damage threshold (LIDT) compared to NYSF crystals. The {110} plane exhibits the highest LIDT due to optimal thermo-mechanical properties, while the {111} plane shows the lowest LIDT due to its minimal flexural strength and weakest thermal shock resistance. A strong linear correlation between radial flexural strength and LIDT further confirms the critical role of intrinsic thermo-mechanical properties in determining the damage resistance for nanosecond laser pulses. This work could provide insights for designing high-power laser gain media and optimizing crystallographic orientations to enhance performance under extreme laser conditions.