Abstract
We tested the use of two hydrophobic methyl-substituted silane precursors, methyltriethoxysilane and dimethyldiethoxysilane, to synthesize methyl-modified silica sols by a two-step method and a cohydrolysis method to produce durable antireflective films with high laser-induced-damage thresholds (LIDTs). Using small-angle x-ray scattering technology, we obtained details of the microstructure of clusters in sol and found various double fractal structural characteristics in the methyl-modified silica clusters; our findings were confirmed by transmission-electron micrographs. Through a magic-angle spin nuclear magnetic resonance study of the corresponding xerogels, we determined the double-fractal microstructure, which we then related to the LIDTs of AR films. The distribution configuration of methyls in clusters determined the double-fractal microstructure of clusters and then the LIDTs of AR films. The LIDTs of films produced by the cohydrolysis method (the highest was 38 J/cm2 for 1-ns, 1064-nm laser action) were much higher than those from the two-step method because of the loose netlike clusters in the former configuration. During the 220-day aging, the transmittance of hydrophobic AR film decreased ∼0.2%. So it is practicable to prepare durable AR films with higher LIDTs than those of normal AR films only by introducing hydrophobic methyls into a Si–O–Si matrix of clusters if an appropriate hydrophobic precursor is chosen.
© 2005 Optical Society of America
Full Article | PDF ArticleMore Like This
Yao Xu, Lei Zhang, Dong Wu, Yu Han Sun, Zu Xing Huang, Xiao Dong Jiang, Xiao Feng Wei, Zhi Hong Li, Bao Zhong Dong, and Zhong Hua Wu
J. Opt. Soc. Am. B 22(9) 1899-1910 (2005)
Yao Xu, Dong Wu, Yu Han Sun, Zu Xing Huang, Xiao Dong Jiang, Xiao Feng Wei, Zhi Hong Li, Bao Zhong Dong, and Zhong Hua Wu
Appl. Opt. 44(4) 527-533 (2005)
Guohang Hu, Yuanan Zhao, Jianda Shao, Kui Yi, Dawei Li, Xiaofeng Liu, and Qiling Xiao
J. Opt. Soc. Am. B 30(5) 1186-1193 (2013)