According to one aspect, the invention relates to an optical security component (10) intended to be observed in a spectral band between 380 and 780 nm and in direct reflection mode, comprising: a layer of dielectric material (101), transparent in said observation spectral band, a continuous metallic layer (102) forming, with said layer of dielectric material, a metal-dielectric interface, having a sufficient thickness (t) to allow the reflection of the incident light on said interface in the observation spectral band with a maximum residual transmission as a function of the wavelength of 2%, and structured at said interface to form, in a first coupling area, two sets of undulations extending in two directions and forming a first grating with two dimensions, of subwavelength periods (Λ1, Λ2) in each of the directions.