An optical authentication component visible in reflection having a structure imprinted on a substrate of index n0, a thin layer, made of a dielectric material having a refractive index n1, deposited on the structure, and a layer made of a material having an index n2 similar to n0, encapsulating the structure coated with the thin layer, is disclosed. The structure has a first pattern modulated by a second pattern, the first pattern is a bas-relief with an array of facets, having shapes which are defined to simulate an image in relief of an object in relief, and the second pattern is a periodic grating that modulates the first pattern which produces, after the thin layer has been deposited and the structure has been encapsulated, a first color at a first viewing angle and a different second color at a second viewing angle, obtained by azimuthal rotation of the component.