The effect of oxygen vacancy on the laser-induced damage behaviors of HfO₂/SiO₂ high reflective coating was investigated by single 355nm-8ns laser. The oxygen vacancy was tuned by controlling the oxygenation of the outmost HfO₂ layer during the deposition procedure. The reflectivity of the coating with higher oxygen vacancy drops by 0.2% and the damage threshold drops by 60%, compared with the normal coating. Damage morphologies of samples were obtained by optical microscope, AFM, SEM and FIB technology. Typical morphologies of these coatings show little difference. Average oxygen vacancy of single HfO₂ layer prepared on the BK7 substrate measured by XPS is about 43%. Theoretical analysis with a nonlinear thermodynamics model shows that the damage can be attributed to nonlinear thermal process. Moreover, the size of damage crater can be interpreted by a mechanics model.

Date Published: 9 July 2013
PDF: 17 pages
Proc. SPIE 8786, Pacific Rim Laser Damage 2013: Optical Materials for High Power Lasers, 878622 (9 July 2013); doi: 10.1117/12.2020363

Published in SPIE Proceedings Vol. 8786:
Pacific Rim Laser Damage 2013: Optical Materials for High Power Lasers
Jianda Shao; Takahisa Jitsuno; Wolfgang Rudolph, Editor(s)