Chinese Optics Letters, Vol. 17, Issue 11, 113101 (2019)
Effect of annealing on the damage threshold and optical properties of HfO2/Ta2O5/SiO2 high-reflection film
Jianing Dong, Jie Fan*, Sida Mao, Yunping Lan, Yonggang Zou, Haizhu Wang, Jiabin Zhang, and Xiaohui Ma
- State Key Laboratory of High-Power Semiconductor Laser, Changchun University of Science and Technology, Changchun 130022, China
The effect of thermal annealing on the optical properties, microstructure, and laser-induced damage threshold (LIDT) of HfO2/Ta2O5/SiO2 HR films has been investigated. The transmission spectra shift to a short wavelength and the X-ray diffraction peaks of monoclinic structure HfO2 are enhanced after thermal annealing. The calculated results of the m(−111) diffraction peak show that the HfO2 grain size is increased, which is conducive to increasing the thermal conductivity. Thermal annealing also reduces the laser absorption of high-reflection films. The improvement of thermal conductivity and the decrease of laser absorption both contribute to the improvement of LIDT. The experimental results show that the highest LIDT of 22.4 J/cm2 is obtained at 300°C annealing temperature. With the further increase of annealing temperature, the damage changes from thermal stress damage to thermal explosion damage, resulting in the decrease of LIDT.