EIT based tunable metal composite spherical nanoparticles

Optical polarizability of a composite metal-dielectric and dielectric-metal spherical nanoparticle is investigated in view of achieving all-optical tunability. In this work, the Electromagnetically Induced Transparency (EIT) implemented in the shell or core of the nanoparticle is used. For the proposed nanoparticle, we show that EIT phenomenon can be utilized to tune the resonance frequency in the frequency response of polarizability. We present a quasi-static analysis for determining polarizability of the nanoparticle. According to our simulation results, all-optical tunability of polarizability can be achieved for reasonable values of optical pump power. Also, we demonstrate how the extinction quality factor and electric field distribution can be controlled for the introduced nanoparticle.