A New Type of Optical Antenna: Plasmonics Nanoshell Bowtie Antenna with Dielectric Hole

We first investigate plasmonic nanoshell bowtie nanoantenna with dielectric hole that interact with incident plane wave of transverse-magnetic polarization by use of the finite element method. The influence of the dielectric hole in nanoshell on the antenna field enhancement and spectral response is discussed. Results show that the proposed plasmonic nanoshell bowtie antenna can confine the field in a volume well below the diffraction limit and exhibit tunable surface plasmon resonances in a wider range of wavelength that are not observed for the conventional solid-gold case with the same volume. This offers a new possibility to further optimize the performance of optical nanoantenna.