Dual Symmetry Breaking in Gold-Silica-Gold Multilayer Nanoshells

In this study, the optical properties induced by dual symmetry breaking including both shell cutting and core offsetting in the gold-silica-gold multilayer nanoshells have been studied by the discrete dipole approximation simulations and the plasmon hybridization theory. The influences of the incident polarization and geometrical parameters on the plasmon resonances of these dual-symmetry-breaking Au-silica-Au multilayer nanoshells (DSMNS) are investigated. Under the combined effect of the two types of symmetry breaking, it is found that the polarization-dependent multiple plasmon resonances can be induced in the DSMNS. By changing the polarization of 90o, the switching of the two transparency windows can be flexibly adjusted in the DSMNS with different types of Au core offsetting. This polarization-controlled transparency is likely to generate a wide range of photonic applications such as filters and color displays. Furthermore, the local refractive index sensitivity of the DSMNS is also investigated, and the triple extinction peaks simultaneous shift is found as the surrounding medium changed, which suggests the potential applications for biological sensors.