Contamination driven laser-induced damage threshold of optical components in the 1µm wavelength regime

Contaminations can lead to a reduction of the laser-induced damage threshold (LIDT) leading to an unexpected damage of the components coating inducing damaged areas significantly larger than the beam size. In this study, we developed a process to contaminate the surface of anti-reflective and high-reflective coated optics with Polyether ether ketone particles of the size 10-100 µm. Contaminated samples were then irradiated with a ns-pulsed high repetition 1 µm laser system regarding the determination of the LIDT. We especially illustrate detection as well as the irradiation and monitoring of a single particles during laser irradiation. In conclusion, we have not observed any damages on clean samples up to an energy density of 1 J/cm². However, the particles got already damaged one to two magnitudes below this leading to a significant decrease in the surface damage threshold.