Radiation pattern control of core shell nanoantenna by manipulation of nonlinear properties

Abstract

In this article, a new structure of core–shell spherical nanoparticle as nanoantenna has been evaluated in which the main lobe direction of its radiation pattern is controllable. In other words, the main lobe direction of core–shell nanoantennas are rotated by using of nonlinearity and pumping secondary wave. As a matter of fact, a unique method is presented in order to turn and tune the radiation pattern of nanoantenna in a considered direction. The control of core shell nanoantenna’s main lobe direction is done by manipulation of the nonlinear properties and an excitation wave as secondary pump. Specifically, Increase in pumping leads to motivate the nonlinear properties of the proposed nanoantenna, therefore the main lobe of radiation pattern is turned slowly and its direction is changed. Based on this method, the designers can implement the structures which have been the controllable scatterings in specific directions. Basically, we indicated that it is possible to control the main lobe direction by means of nonlinear perturbation in core–shell nanoantenna and incidence of secondary wave. For more study, the effect of existence of substrate under spherical nanoantenna is investigated and variation of its pattern is also illustrated. The constituent materials of structures have nonlinear properties. The obtained results in final section show that the substrate also plays effective role in directing of nanoantenna’s beam. Turning lobe direction of presented nanoantenna is evaluated on 600 THz as well.