Optical authentication component and method of fabricating said component

An optical authentication component visible in reflection, comprising:

• at least one structure imprinted on a substrate of refractive index n0;
• a thin layer having a thickness between 50 and 150 nanometers, made of a dielectric material having a refractive index n1 different from n0, deposited on said at least one structure;
• and
• a layer, made of a material having a refractive index n2, encapsulating the at least one structure coated with the thin layer, wherein n2 is approximately the same as n0,
• wherein the at least one structure comprises a first pattern and a second pattern that modulates the first pattern:
• the first pattern being a bas-relief comprising an array of facets the shapes of which are defined in order to simulate an image in relief of an object in relief;
• the second pattern being a periodic grating that modulates the first pattern in order to produce, after the thin layer has been deposited and said at least one 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 optical authentication component.