Local interaction of light with periodic photonic structures

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

Near-field optical studies of photonic structures

Local optical investigations of light propagation have the advantage that the optical phenomena can be directly related to the local geometry of the photonic structure. As such, near-field optical microscopy ideally complements conventional "input-output" techniques

Coherent imaging of local fields in photonic crystals

Summary form only given.\ud In the past years, much research has been focused on so called photonic crystals. Different ways of fabricating and simulating these structures have been introduced. Characterization is performed mostly with black box experiments, where reflected or transmitted light is detected. We demonstrate a different approach, which allows us to take a direct look inside such structures. With a heterodyne interferometric photon scanning tunneling microscope (PSTM), we are able to visualize not only the amplitude of the local optical field, but also the phase information of light propagating inside the crystal. Heterodyne interferometric photon scanning tunneling microscopy gives detailed insight in reflected and transmitted waves as they develop through periodic structures. Ultimately, this method will allow us to visualize the opening of a stop gap in one or two-dimensional photonic crystals

Large area photonic crystal slabs for visible light with waveguiding defect structures: Fabrication with focused ion beam assisted laser interference lithography

Extended photonic crystal slabs with light-guiding defects have been created by a combination of laser interference lithography (LIL) and local focused ion beam (FIB) assisted deposition. Large area, highly uniform photonic crystal slabs for visible light are thus made possible. The Figure shows a freestanding Si3N4-air photonic crystal with a light- guiding defect line running along the center of the slab (total length = 1 mm)