Substantial improvements in the properties and performance of optical coatings have been obtained by retrofit of a 96-inch vacuum evaporation coating chamber with a high-current, low-voltage ion gun for ion-assisted deposition. Improved optical coatings for large laser optics, astronomy mirrors, or batch production of small or midsize optics are now available, without the need for substrate heating. This paper presents the technical approach and the earliest results for recent successful ion assist implementation in Itek''s largest coating chamber. Optimal use of ion assist in harmony with the evaporation process is described, and chamber geometry, ion gun installation, and related technical issues are briefly discussed. Property enhancement data are presented for several classes of coating materials, including oxides, fluorides, and sulfides. Improvements in refractive index, density, abrasion resistance, adhesion, mechanical stress, and stability to temperature and humidity exposure are included. Results for large optics coated to date are presented
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