A method for guiding electromagnetic radiation by providing a photonic crystal made of a bulk material with a predetermined refractive index and having a periodic array of holes with predetermined radius, and feeding to that region an electromagnetic radiation having a wavelength in the fundamental photonic band and so related to the refractive index of the bulk material, to the radius of the holes and to the period of the array that, starting from an isotropic distribution of the wave vectors within a first angular range that is twice the angular extension of the first irreducible Brillouin zone of the photonic crystal, the corresponding group velocity vectors are rearranged as concerns direction and module so that at least 50% of them become directed within a second angular range that is about one-third of the first angular range and the width at half-maximum of the distribution of the modules of the vectors is lower than about two-thirds of the second angular range.