The invention concerns an optical coating (3, 3′), having a high refractive index and good optical properties (i.e., low absorption and scatter) and limited internal stresses in a spectral range extending from the visible to the near UV range (i.e., up to a wavelength of 220 nm). The coating (3, 3′) according to the invention consists of a hafnium- or zirconium-containing oxide HfxSiyOz or ZrxSiyOz containing an silicon fraction (y) between 1 at. % and 10 at. %, especially between 1.5 at. % and 3 at. %.