Investigation of directivity of the nanoantenna by its inherent resonant states

We present a quasinormal mode (QNM) approach for modeling the nanoantenna and describe the response of localized dielectric cylinder resonators. The inherent resonant states of the dielectric cylinder nanocavity are investigated for modified and reduced geometrical symmetry. We find some modes contributing mainly to the directivity and have a high-quality factor. The variation of the eigenmodes with cylinder height and substrate refractive index has also been investigated.