Investigation of laser induced damage threshold measurement with single-shot on thin films

A method for rapid determination of laser induced damage threshold (LIDT) of optical coatings is proposed and investigated in this paper. By use of this method, the LIDT of thin film can be rapidly obtained by only one shot. The modulation of laser beam profile, which is considered as a negative factor in conventional LIDT test, is utilized in this method. Basing on image processing technique, the damage information could be extracted from the comparison between the damage pattern and beam intensity distribution in the test region. The applicability and repeatability of this testing method has been verified on three type reflectors, HfO2/SiO2, HfO2/Al2O3 and Ta2O5/SiO2. In addition, the experimental results showed that appropriate beam size, laser energy and image compression ratio are the key factors to ensure a high accuracy of LIDT.