The characteristic parameters of initiating defects in HfO2/SiO2 high-reflector multilayer thin film at wavelength of 1064 nm

The characteristic parameters of initiating defects in HfO2/SiO2 high-reflector film at wavelength of 1064 nm are investigated through the combined application of laser-conditioning process and the multi-spot damage threshold test. The laser damage tests before and after laser-conditioning are carried out within three different spot diameters. The damage threshold and the density are considered to characterize the initiating defects which are shown to be susceptible to laser damage. These characteristic parameters are obtained through fitting the damage data with the spot size effect. The influence of laser-conditioning effect on the initiating defects is analyzed. The initiating defects are specified by a Gaussian distribution after laser-conditioning. It is discussed the essential roles of the initiating defects to the damage threshold of the film. The investigation on characteristic parameters of initiating defects has potential to be applied in the mechanisms of laser induced damage and laser-conditioning, as well as in the direction the preparation of the films.