Light refraction, i.e. the bending of the path of a light wave at the
interface between two different dielectric media, is ubiquitous in optics.
Refraction arises from the different speed of light and is unavoidable in
continuous media according to Snell's Law. Here we show rather
counterintuitively that omnidirectional refractionless propagation can be
observed for discretized light crossing a tilted interface separating two
homogeneous waveguide lattices.Comment: 6 pages, 4 figures, to appear in Optics Letter
