The invention relates to a plasmonic optical security component comprising two layers (2, 4) made of transparent dielectric material and a metal layer (3) arranged between said transparent dielectric material layers in order to form two dielectric-metal interfaces (31, 32). The metal layer is structured to form, on a first coupling region, a first periodic, two-dimensional coupling array (C1) which is capable of coupling surface plasmon modes, which are supported by said dielectric-metal interfaces, to an incident light ray, the first coupling array having a profile which does not have point symmetry in any of the directions thereof, and, on a second coupling region, a second periodic, two-dimensional coupling array (C2) which is capable of coupling surface plasmon modes, which are supported by said dielectric-metal interfaces, to an incident light ray, the second coupling array having a profile which does not have point symmetry in any of the directions thereof and is different from that of the first coupling array.