Fig. 2
Square of near electric field amplitude |E|2 plots of the four structures shown in Fig. 1 at their corresponding dipolar resonance peak wavelengths. a and b are plotted for (80-nm-diameter silica core)@(15-nm-thick gold shell) at 700 nm. c and d are plotted for (80-nm-diameter silica core)@(25-nm-thick gold shell) at 684 nm. e and f are plotted for (80-nm-diameter silica core)@(35-nm-thick gold shell) at 706 nm. g and h are plotted for (80-nm-diameter silica core)@(45-nm-thick gold shell) at 756 nm. The left column, i.e., a, c, e, and g, shows |E|2 calculated with bulk gold’s dielectric constants from reference [38]. The right column, i.e., b, d, f, and h, shows |E|2 calculated with gold’s dielectric constants modified with surface scattering via Eqs. (1)~(3). The polarization and the propagating direction of the incident light are same for all figures and are shown in a. Simulation is conducted by the software “FDTD Solutions,” with the grid size of three-dimensional mesh override region being 1 nm