The Enhancement in Optical Characteristics of Nano-Antenna Arrays through Addition of Inverse Active Core-Shell Nanoparticles in the Array Element

We demonstrate analytically the technique and arrangement of nanoparticle antenna arrays with the enhancement of optical characteristics at an optical frequency regime. The optical characteristics of the array are enhanced by introducing an inverse active spherical coated nanoparticle (I-CNP). This inverse active spherical coated nanoparticle is designed and combined with already demonstrated active CNPs. Consequently, three types of active CNPs and their inverse-based plasmonic nano-antenna array configurations have been designed and studied: two CNP configurations, two inverse CNP (I-CNP) configurations and a CNP with an I-CNP configuration in the presence of passive elements. Detailed near-field analysis contains an E-field, radiated power, scattering and absorption examination, whereas far-field analysis includes gain and pattern investigation. The finite-difference time-domain (FDTD) simulation results in CST depict the benefits of a CNP with an I-CNP array configuration in the presence of passive elements over the other two in terms of both near-field and far-field characteristics, at closer inter-element distances because of coupling avoidance with possession of a dipolar pattern.