An interference filter, including a first interface layer; a first dielectric portion of a first dielectric material, having a first thickness and resting on the first interface layer at a first location; a second dielectric portion of the first dielectric material, the second dielectric portion resting on the first interface layer at a second location, the second dielectric portion having a second thickness greater than the first thickness; a third dielectric portion of a second dielectric material having a refraction index smaller than the refraction index of the first material, the third dielectric portion having a third thickness and resting on the first dielectric portion, the sum of the first thickness and of the third thickness being equal to the second thickness; and a second interface layer resting on the second and third dielectric portions.