Photonic crystals: imaging by flat lens using negative refraction.
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.
Parimi
Patanjali V
PV
Department of Physics and Electronic Materials Research Institute, Northeastern University, Boston, Massachusetts 02115, USA.
Lu
Wentao T
WT
Vodo
Plarenta
P
Sridhar
Srinivas
S