Ion-assisted deposition (IAD) has been used to deposit magnesium fluoride, cryolite (Na3A1F6), and lanthanum fluoride films on ambient temperature substrates. IAD magnesium fluoride coatings show increased density and moisture resistance, while IAD lanthanum fluoride coatings exhibit increased refractive indices. Cryolite films, however, do not significantly benefit from IAD. Oxygen, rather than argon, as the bombarding species reduces bombardment-induced absorption in the visible, but may produce an additional oxide absorption edge in the ultraviolet.
|