Numerical evidence of ultrarefractive optics in photonic crystals

This paper is devoted to a numerical demonstration of a conjecture of specialists of photonic band structures: the existence of ultrarefractive optics phenomena. Near the edges of a transmission gap, the permittivity of a dielectric photonic crystal becomes close to zero. As a consequence, surprising refractive effects should be observed on the light transmitted and reflected by a slice of photonic crystal. A property of beam translation very similar to the Goos-Hanschen effect (but in transmission) is shown, as well as a strange phenomenon: a beam incident on a slice of photonic crystal can be enlarged or even split into some separate transmitted beams. (C) 1999 Elsevier Science B.V. All rights reserved.