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.
- Publication:
-
Nature
- Pub Date:
- November 2003
- DOI:
- 10.1038/426404a
- Bibcode:
- 2003Natur.426..404P