| Abstract | Nanoantennas for visible and infrared
radiation can strongly enhance the interaction of light
with nanoscale matter by their ability to efficiently link
propagating and spatially localized optical fields. Gold
nanoparticles are the material that is mostly used
experimentally, since it combines a favorable dielec-
tric function in the red and near-IR with excellent
chemical stability. So, the gold material is used to build
nanoantennas in this research. The optical properties of
plasmonic dimer nanoantennas are investigated in
detail using the finite integration technique. The
validity of this technique is verified by comparison to
the exact solution generalized Mie method (GMM).
The influence of the geometrical parameters (antenna
length, gap dimension, and shapes) on the antenna field
enhancement and spectral response is discussed.
Localized surface plasmon resonances of Au (gold)
dimers nanospheres, bowtie and aperture bowtie
nanoantennas are modeled. The enhanced field is
equivalent to a strong light spot which can lead to the
resolution improvement of the microscopy and optical
lithography, thus increasing the optical data storage
capacity. Furthermore, the sensitivity of the antennas
to index changes of the environment and substrate is
investigated in detail for biosensing applications. We
confirm that our approach yields an exact correspon-
dence with GMM theory, for Au dimers nanospheres at
gap dimension 5 and 10 nm but gives an approximation
error of less than 1.37 % for gap dimension 1 and 2 nm
with diameters approaching 80 nm. In addition, the
far-field characteristics of the aperture bowtie nano-
antenna such as directivity and gain are studied. The
promising results of this study may have useful
potential applications in near-field sample detection,
optical microscopy, etc |