Wang X, Wu G, Zhou B, Shen J
Improvement on laser-induced damage threshold of sol-gel ZrO2 coatings by crystal structure tuning.
Optics express. 2012 Oct 22; 20: 24482-7.
With the development and construction of high peak power lasers it has become more and more important to improve the laser-induced damage threshold (LIDT) of optical coatings. In this paper, ZrO2 coatings were deposited by sol-gel dip-coating method and further treated by conventional furnace annealing (CFA) and rapid thermal annealing (RTA) at different temperatures. By measuring the Raman spectra, optical constants and LIDT, the influence of annealing on the crystal structures, refractive indices, laser-induced damage characters of ZrO2 coatings were analyzed. The results show that RTA is effective in tuning the crystal structures of ZrO2 coatings. Lattice mismatch between monoclinic and tetragonal phases happened on CFA treated film reduces its refractive index, hence the film annealed by RTA at 800 °C realizes a higher refractive index. Compared with CFA annealed films, RTA annealed films were no more susceptible to laser damage due to their crystal structure difference caused lager band gap.