High-Damage-Threshold Mirror Coatings for Pulsed and CW Laser Applications
High-Damage-Threshold Mirror Coatings for Pulsed and CW Laser Applications Introduction Laser-induced damage remains the single most common reason optics fail in high-power systems. A mirror coating that performs flawlessly at 5 J/cm² in a continuous-wave (CW) setup can fracture catastrophically when hit with a 10-nanosecond pulsed beam at the same fluence. The physics differ, the failure modes differ, and the coating designs must differ accordingly. Engineers specifying optics for laser systems face a difficult trade-off: maximize reflectance, minimize absorption, and push the damage threshold as high as the substrate and coating stack will allow. Traditional off-the-shelf mirrors often fall short because their coatings are optimized for imaging or illumination, not for surviving megawatt-level peak powers. This guide walks through the practical steps of selecting, specifying, and validating high-damage-threshold mirror coatings for both pulsed and CW laser applications. It cover...