Advances in sub-wavelength photonics

The physics and technology of sub-wavelength structured optical materials such as photonic crystals, patterned metallic films and, more generally, artificial optical materials, such as metamaterials (i.e. structured materials with new characteristics obtained by combining materials properties and geometrical patterning), offer novel phenomena and applications over and above classical integrated optics - mainly because of their unique dispersion characteristics, which include photonic band-gap behaviour and slow propagation of light. The associated strong optical confinement has already led to much more compact devices and enhanced non-linear effects, implying the possible replacement of electronic functionality by ultra-fast all-optical operation. This contribution discusses advances and challenges in sub-wavelength photonics, and it reports on the research agenda of a European project COST Action MP0702: Towards Functional Sub-Wavelength Photonic Structures.