| Abstract | The optical properties of plasmonic nanoantennas are investigated in detail using the finite integration technique (FIT). 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 sh
apes) 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 correspondence with GMM theory for Au dimers nanospheres at gap dimensions 5nm and 10nm but gives an
approximation error of less than 1.37% for gap dimensions 1nm and 2nm with diameters approaching 80nm. In addition, the
far-field characteristics of the aperture bowtie nanoantenna su
ch as directivity and gain are studied. The promising results of this
study may have useful potential applications in near-field sample detection, optical microscopy, and so forth |