Optical properties of several ternary nanostructures

To investigate the optical properties of the ternary nanostructures, the nanodisk, core–shell, and three-sphere structures are constructed. The extinction coefficients and electric near-field distributions of these structures are calculated by the discrete dipole approximation(DDA) method. The result shows that the nanodisk structure has the best extinction efficiency in the three structures. Furthermore, several three-material combinations of the nanodisk structures are investigated. The ternary nanodisk structure composed of TiO_(2) and two noble metals(Au, Ag or Pt) has higher extinction coefficient and near-field intensity than the nanodisk consisting of Au, TiO_(2) and a semiconductor(Pb Se, Ge, MoS2, CdSe, CdS or TiO_(2)).Especially, TiO_(2)/Ag/Pt has the best extinction efficiency and the max electric near-field intensity. And the extinction spectra of TiO_(2)/Ag/Pt and TiO_(2)/Ag/Au structures are complementary in the visible range. This work conduces to the further research into ternary nanostructure and provides essential information about its performance in visible range.