Full text loading...
Extinction spectra. Jagged curve: data (Ref. 14) for a particle in silica bead, smooth curve: theoretical fit with , , and , and the thickness of the bead 12 nm. Arrow indicates a shoulder reproducible with the arms having triangular crossection. Insets: (a) SEM image of a Ag octopod from Ref. 14. (b) A view of a typical octopod along the fourth order symmetry axis, , where , , and are the geometric parameters.
Extinction spectra of sphere and multiarm nanoparticles, all with the same effective radius 81.4 nm. Plasmonic resonances marked by numbers 1 to 3, with quadrupole resonances 1 and 2 (marked Q1, Q2), and the long wavelength dipole resonance 3 (marked D). The ratio of is, from left to the right: 1 (sphere), 1.6, 2.0, and 2.4. All the nanostars have the same ratio . The inset shows decomposition of the extinction efficiency into absorption (A) and scattering (S) contributions for as a function of the wavelength .
(a) Three-dimensional dipole distributions at time for the SPRs 1, 2, and 3. The up and down arrows show local dipoles directed along or against the external electric field. The hot spots lie in the planes marked by the solid vertical lines. (b) Two-dimensional electric field distributions on the “hot spot” planes. The vectors are shown as the arrow field, with shades corresponding to those shown by arrows in the far left. The lengths of the arrows is proportional to . The big arrows mark the hot spots. (c) Same as in (b), but for the magnetic field.
Article metrics loading...