Laser Damage Threshold

Laser damage to optical filters is strongly dependent on many factors, and thus it is difficult to guarantee the performance of a filter in all possible circumstances. Nevertheless, it is useful to identify a Laser Damage Threshold (LDT) of pulse fluence or intensity below which no damage is likely to occur. Laser damage may be broadly classified into two types: absorption-driven and dielectric-breakdown damage. Which type dominates depends on the material properties (absorption coefficient, specific heat, melting temperature, as well as defects that cause scattering and concentrated electric field effects), geometric properties of the sample (thickness, homogeneity, surface morphology, etc.), and of course the properties of the laser beam itself.