Yagi–Uda nanoantenna For NIR domain

Abstract

Single component metal nanoparticles, such as Ag and Au, have surface plasmon resonance wavelengths in the visible region having a weak dependence on particle size. For double component (core/shell) nanoparticles, by proper tuning the core size and shell thickness, a wide variation in optical radiation characteristics as well as in surface plasmon resonance wavelength up to Near-Infrared (NIR) region can be achieved. These aspects encourage one to model an optical Yagi–Uda antenna adopting core/shell nanoparticles as feed element, reflector and directors. In this paper, adopting the COMSOL Multiphysics software, we design all core/shell Yagi–Uda nanoantennas in the NIR domain. $$\hbox {SiO}_{2}/\hbox {Au}$$ core/shell nanoparticles are taken as antenna elements for the proposed antenna, whose surface plasmon resonance wavelength can be shifted to the NIR region by tuning the core to shell size ratio in a particular size band. The optimized directivity and gain for this antenna is achieved with only one reflector and one director, thus making it ultra-compact, cost-effective and simple in structure. This type of very highly directional Yagi–Uda nanoantenna can be used in medical science such as in targeted drug delivery and in wireless optical communication.