Chinese Optics Letters, Vol. 5, Issue 8, 487 (2007)
Effects of water vapor in high vacuum chamber on the properties of HfO2 films
Bo Ling1,2,*, Hongbo He1,2, and Jianda Shao1
- 1Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800
- 2Graduate School of the Chinese Academy of Sciences, Beijing 100039
The influence of water vapor content in high vacuum chamber during the coating process on physical properties of HfO2 films was investigated. Coatings were deposited on BK7 substrates by electron beam evaporation and photoelectric maximum control method. An in situ residual gas analyzer (RGA) was used to monitor the residual gas composition in the vacuum chamber. The optical properties, microstructure, absorption and laser-induced damage threshold (LIDT) of the samples were characterized by Lambda 900 spectrophotometer, X-ray diffraction (XRD), surface thermal lensing (STL) technique and 1064-nm Q-switched pulsed laser at a pulse duration of 12 ns respectively. It was found that a cold trap is an effective equipment to suppress water vapor in the vacuum chamber during the pumping process, and the coatings deposited in the vacuum atmosphere with relatively low water vapor composition show higher refractive index and smaller grain size. Meanwhile, the higher LIDT value is corresponding to lower absorbance.
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