A review of contamination-resistant antireflective sol-gel coatings

Sol-gel derived silica antireflective (AR) coatings have been widely used as the optical components for high peak power laser systems because of their excellent optical properties and high laser-induced damage thresholds. However, the sol-gel derived coatings have a high surface area that is more susceptible to be contaminated by absorption of trace amounts of water vapor and other volatile organic compounds from the environment. In this paper, the major approaches to fabricate contamination resistant sol-gel derived silica AR coatings have been extensively reviewed. Different approaches, including solution-phase and vapor-phase silanization, ammonia-water vapor treatment and fluorine modification have been discussed. The optical properties and laser-induced damage thresholds of modified coatings have also been evaluated. The improved sol-gel AR coatings have been shown to possess superior contamination resistance to work in vacuum systems compare to the traditional sol-gel AR coatings.