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Nanostructured magnesium fluoride (MgF 2 ) antireflective films with ultra-high laser induced damage thresholds (LIDTs) have been prepared through dip coating of ~10 nm MgF 2 nanoparticles on fused silica substrates. The films increase transmittance from 93.0% for bare substrates to 99.98% for coated substrates. The LIDTs of the nanostructured MgF 2 films reach as high as 25 J/cm 2 at 351 nm, 34 J/cm 2 at 527 nm and 63 J/cm 2 at 1053 nm, respectively. The LIDTs of the nanostructured MgF 2 films is higher than that of dense MgF 2 films and sol–gel derived silica films. Such high LIDTs of the nanostructured MgF 2 films may be attributed to the large band gap and the quantum size effect of the MgF 2 nanoparticles. These nanostructured MgF 2 films will be utilized as antireflective films used in high-peak-power laser system.

Silica antireflective films by the base catalyzed sol–gel process show poor mechanical property. In this study, silica antireflective films with good mechanical property have been prepared by the acid catalyzed templating sol–gel process. The single-layer film was deposited from an acid-catalyzed silica sol solution with polymer F127 incorporation. The silica sol was first dip deposited onto substrate to form films on both sides of the substrate and then subjected to thermal treatment at 500 °C. After thermal treatment, the abrasion resistant antireflective film was achieved due to the formation of porous structure in the resultant film as a result of decomposing F127. Optical spectroscopic measurement shows that the coated glass with maximum transmittance of 99.5% has been obtained. Nanoindenter measurement shows that the elastic modulus and hardness of films are 16 GPa and 1.3, respectively, which are much better than those films derived from base-catalyzed silica sols. The high transmittance and good mechanical property make such films potential in both military and civil applications.