The structure of light at the nanoscale

Through the use of novel near-field microscopy techniques we gained an unprecedented insight into the structure of light around nanophotonic structures. We related the in-plane spatial distribution of vortices above a 3D photonic crystal to its residual disorder. Maps of the light field in three-dimensions above photonic crystal waveguides reveal that the complex evanescent field of a Bloch mode is determined by its build-up from Bloch harmonics each of which may have a different lateral structure, leading to a modified multi-exponential decay.
We experimentally showed how polarization at the nanoscale should be measured. Access to the nanoscale polarization provided proof of the existence of polarization singularities in non-transverse fields and unravelled the mode symmetries of plasmonic nanowire and slot waveguides. The sensitivity to vector fields combined with the use of tailored near-field probes allowed the direct visualization of the magnetic field of light. We induced a resonance blue shift and an increased the cavity Q through a light-matter interaction mediated by the magnetic component of light trapped in a photonic nanocavity.