Multilayer dielectric optical coatings, nominally consisting of 1000 or more optical-quarterwave layers, have been prepared by reacting SiCl4 and a halogenated dopant (e.g. GeCl4) with O2 in a microwave-driven plasma. The dopant concentration is such that the index difference (An) between adjacent quarterwave layers is about 0.02 or less. The deposition is carried out at high substrate temperatures (850 to 1100°C) producing a fully dense, fused silica coating. Surface damage thresholds of high reflectivity (HR) coatings prepared by this plasma process are comparable to those for fused silica. For example, at 1.06 μm and 16-ns we measure surface damage thresholds greater than 45 J/cm2 compared to about 45–60 J/cm2 for super-polished optical fused silica.