Local interaction of light with periodic photonic structures

Photonic crystals are structures with a strong relation between geometry and op- tical properties. The application of near-field methods is a new and challenging approach to investigate the local optical properties of photonic crystals. The op- tical signals obtained in crystal structures of various dimensionalities can be di- rectly related to the local geometry of the structure. In contrast to this local probe technique that enables sub-wavelength resolution, far-field approaches return in- formation that is spatially averaged. Reflectivity experiments, for example, reveal the long-range quality of a crystalline structure or the effect of stopgaps on the overall light propagation. By combining the complementary near-field and far-field results, a complete picture of the optical properties in a photonic crystal structure emerges.