Single-shot large beam laser induced damage threshold measurement on dielectric coatings

A novel method for laser induced damage threshold (LIDT) test of dielectric coatings is discussed in order to solve the time-consuming problem in traditional LIDT test. Single shot with large beam is used to get the LIDTs based on image processing technique. Following the coordinate conversion, image girding and compression procedure, the damage information could be extracted by comparing the sub-damage-spots distribution with the laser intensity distribution in the irradiated region. And finally the LIDT could be obtained from this information. This new method could greatly increase the efficiency of LIDT test. Moreover, the single-shot large beam LIDT testing bench is introduced and the availability of this method is confirmed on HfO₂/SiO₂ high reflectors. (authors)