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.
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