When sourcing laser mirrors, you must prioritize Substrate Material (such as Silicon, Molybdenum, or K9 Glass) based on the laser's power. For high-power CO2 lasers, Silicon (Si) or Molybdenum (Mo) are preferred due to their high thermal conductivity. You must also verify the Reflectivity Rate, which should ideally be ≥99.2% to minimize energy loss. Additionally, check the Surface Quality (Scratch-Dig); a standard of 40-20 or better is required for precision industrial applications to prevent beam distortion.