title: Three-dimensional study of planar optical antennas made of split-ring architecture outperforming dipole antennas for increased field localization.
abstract: Optical antennas are of fundamental importance for the strongly localizing field beyond the diffraction limit. We report that planar optical antennas made of split-ring architecture are numerically found in three-dimensional simulations to outperform dipole antennas for the enhancement of localized field intensity inside their gap regions. The computational results (finite-difference time-domain) indicate that the resulting field localization, which is of the order of many thousandfold, in the case of the split-ring resonators is at least 2 times stronger than the one in the dipole antennas resonant at the same operating wavelength, while the two antenna types feature the same gap size and tip sharpness.
authors.affiliation: Department of Electrical and Electronics Engineering, Bilkent University, Ankara, Turkey.
authors.forename: Veli Tayfun
authors.initials: VT
authors.lastname: Kilic
authors.forename: Vakur B
authors.initials: VB
authors.lastname: Erturk
authors.forename: Hilmi Volkan
authors.initials: HV
authors.lastname: Demir