title: Photonic crystals: imaging by flat lens using negative refraction.
abstract: The positive refractive index of conventional optical lenses means that they need curved surfaces to form an image, whereas a negative index of refraction allows a flat slab of a material to behave as a lens and focus electromagnetic waves to produce a real image. Here we demonstrate this unique feature of imaging by a flat lens, using the phenomenon of negative refraction in a photonic crystalline material. The key advance that enabled us to make this observation lies in the design of a photonic crystal with suitable dispersion characteristics to achieve negative refraction over a wide range of angles.
authors.affiliation: Department of Physics and Electronic Materials Research Institute, Northeastern University, Boston, Massachusetts 02115, USA.
authors.forename: Patanjali V
authors.initials: PV
authors.lastname: Parimi
authors.forename: Wentao T
authors.initials: WT
authors.lastname: Lu
authors.forename: Plarenta
authors.initials: P
authors.lastname: Vodo
authors.forename: Srinivas
authors.initials: S
authors.lastname: Sridhar