Abstract
Quarterwave antireflective coatings of CaF2 and MgF2 have been prepared on fused silica and calcium fluoride substrates from colloidal suspensions of the relevant fluorides in methanol. These coatings have high optical efficiency and laser damage thresholds at 350 nm in the 6–8-J/cm2 range for single shots of 0.6-ns pulse length and 20–25 J/cm2 for 25-Hz multishots of 25-ns pulse length.