Near-field mapping of the electromagnetic field in confined photon geometries

We study the optical modes in resonator structures obtained by assembling microcavities with a three-dimensional confinement of light. We used scanning confocal microscopy in order to measure light emission from these structures in the near optical field. Our studies give direct and detailed insight into the spatial distribution of the electromagnetic fields of confined modes in these photonic structures. We find similarities between the spatial modes of two coupled resonators and those of a diatomic molecule, and between modes of a chain of resonators and those of a periodic molecular crystal. In particular, we show that deviations of cavity size in the chain give rise to localized photonic modes which resemble impurity states in molecular crystals.