title: Generalized laws of refraction that can lead  to wave-optically forbidden light-ray fields.
abstract: The recent demonstration of a metamaterial phase hologram so thin that it can be classified as an interface in the effective-medium approximation [Science 334, 333 (2011)] has dramatically increased interest in generalized laws of refraction. Based on the fact that scalar wave optics allows only certain light-ray fields, we divide generalized laws of refraction into two categories. When applied to a planar cross section through any allowed light-ray field, the laws in the first category always result in a cross section through an allowed light-ray field again, whereas the laws in the second category can result in a cross section through a forbidden light-ray field.
authors: SUPA, School of Physics & Astronomy, University of Glasgow, Glasgow, UK. johannes.courtial@glasgow.ac.uk
authors: Johannes
authors: J
authors: Courtial
authors: Tomáš
authors: T
authors: Tyc