Microcavities with 3D optical confinement

We have fabricated microcavities with three-dimensional optical confinement by the combination of epitaxially grown vertical cavity surface emitting cavity structures and lithographic patterning. The emission spectra of semiconductor pillars fabricated by this technique show a number of optical modes, which can be tuned by changing the lateral dimensions of the structures. By using angle-resolved photoluminescence spectroscopy, the dispersion of the optical modes in these photonic dots has been investigated. In contrast to microcavities with confinement in one direction only, microcavities with three-dimensional optical confinement show no dispersion of the mode energies in angle resolved photoluminescence experiments. Studies of 1D photonic wires show suppression of dispersion perpendicular to the wires whereas dispersion is observed along the 1D structures. By investigations of the far field intensity distribution of different modes, information on the internal electromagnetic field distributions is obtained. The energies of the optical modes in the photonic dots as well as the intensity variations in angle resolved experiments have been modelled by numerical approaches, which agree quantitatively with the experimental results.