多层介质膜激光诱导损伤改进模型与实验研究OA

The structure of multilayer dielectric film will modulate the optical field,thus in the study of laser-induced damage characteristics,it is necessary to consider the energy distribution within the film system and the resulting changes in material optical properties.Taking the HfO2/SiO2 multilayer dielectric film structure as an example,and based on the laser-induced ionization/electron multiplication process,the Drude model is introduced into the optical field calculation,extending the film layer refractive index from a static constant to a dynamic complex refractive index driven by the free electron density.Based on this,a thermal conduction(and thermal stress)model is coupled to calculate the evolution of thermal effects inside the thin film under nanosecond pulsed laser irradiation,and the corresponding damage threshold is determined to be 13.65 J/cm2,and the damage characteristics of the film are studied experimentally.The verification experiment observed that the damage appearance of the HfO2/SiO2 multilayer dielectric film is a round hole type,which is a typic-al thermal melting damage,and is consistent with the conclusion of the theoretical model.The measured damage threshold is 13.75 J/cm2,which is only higher than the theoretical analysis result.The improved mod-el established is helpful to further analyse the interaction between strong laser and multilayer dielectric film from the theoretical level,and to better study the damage resistance of optical thin film.