Abstract: A transparent substrate and methods of making a transparent substrate having, on at least one of its faces, an antireflection coating made of a multilayer stack of alternating thin layers of high and low refractive indices. Preferably, the thin layers are based on a dielectric material. At least one of the thin high-index layers comprises titanium oxide which is modified so as to reduce its refractive index to a value of at most 2.40, preferably to a value of at most 2.35.