2. Origin of laser damage

Laser damage results from the coupling and transfer of laser energy into the material. Schematically, two main types can be distinguished:

• coupling by residual intrinsic absorption of the material or defects in the material. This mechanism leads to heating and consequent thermal effects in the component;

• coupling by photo-ionization, when the electric field is sufficiently intense to ionize the material and induce electron avalanche effects; this mechanism is non-linear (does not depend linearly on the electric field) and can occur in a perfectly transparent material at low intensity.