All captions are in the order of appearence in the text. FIG. 1: A rigourous representation of the magnetic (a) and electric (b) fields in the vicinity of a circular aperture in a metallic screen. The aperture has subwavelength size and the screen has an infinite conductivity. The fields reduce to uniform far-fields E$_{0}$ , B$_{0}$ incident part of space (-), and to a dipolar field in the other part (+). 17