Investigation of defect, mechanical, thermal properties and refractive index on an Er:LuYSGG mixed laser crystal

We investigate the defect, mechanical, thermal properties, and refractive index of Er:LuYSGG mixed crystal grown by the Czochralski method. The chemical etching pit patterns present a regular tetrahedron, which consists well with the corresponding atomic arrangement schematics. The Mohs hardness is obtained to be 6.60. The thermal expansion coefficient and the thermal conductivity along <111> crystallographic orientation are achieved to be 7.91×10-6 K-1 and 3.423 W m-1 K-1, respectively, indicating the Er:LuYSGG has a relatively high damage threshold. Based on the measured values of refractive index, the Sellmeier equation is fitted and the refractive index curve in the range of 400-3000 nm is displayed. All these results are of great significance for the further research and laser application of Er:LuYSGG crystal.