Breakthroughs in Photonics 2013: Flat Optics: Wavefronts Control With Huygens' Interfaces

Recent progress in the fields of nanophotonics and metamaterials has enabled the development of ultrathin and flat optical components, providing physicists and optical engineers a new method to control light. According to the Huygens-Fresnel principle, light gradually propagates step by step by exciting secondary waves that then reradiate to form the next wavefront; the phase and amplitude of these secondary waves are intimately related to the incoming optical wavefront. By using the response of nanoengineered subwavelength optical resonators at interfaces, it is now possible to engineer Huygens' interfaces to achieve an unprecedented control of the wavefront over large bandwidths and subwavelength propagation distances.