Effect of the interface on femtosecond laser damage of a metal-dielectric low dispersion mirror
Yuhui Zhang, Yanzhi Wang, Ruiyi Chen, Zhihao Wang, Jiaoling Zhao, Dawei Li, Meiping Zhu, Yuanan Zhao, Yunxia Jin, Kui Yi, Yuxin Leng, Ruxin Li, Hongbo He, Jianda Shao
Abstract
Metal-dielectric low dispersion mirrors (MLDM) have a promising application prospect in petawatt (PW) laser systems. We studied the damage characteristics of MLDM and found that the damage source of MLDM (Ag + Al 2 O 3 +SiO 2 ) is located at the metal-dielectric interface. We present the effect of the interface on the femtosecond laser damage of MLDM. Finite element analysis shows that thermal stress is distributed at the interface, causing stress damage which is consistent with the damage morphology. After enhancing the interface adhesion and reducing the residual stress, the damage source transfers from the interface to a surface SiO 2 layer, and the damage threshold can be increased from 0.60 J/cm 2 to 0.73 J/cm 2 . This work contributes to the search for new techniques to improve the damage threshold of MLDM used in PW laser systems.