2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/83406We show numerically for the first time that ultra-refractive phenomena do exist in one-dimensional photonic crystals: we exhibit the main features of ultra-refraction, that is the enlargement and the splitting of an incident beam. We give a very simple explanation of these phenomena in terms of the photonic band structure of these media.5 pages (Revtex), 6 figures (Postscript)OpticsComputational Physicstext