Fig. 6.
Absorption and scattering efficiency of ordered NP chains. (A–D) Scattering (QSCA, blue) and absorption (QABS, magenta) efficiencies of linear chains composed of 2 (A), 3 (B), 6 (C), and 10 (D) 40-nm gold NPs. The efficiency Q is defined as the optical cross section normalized by the geometric cross-section of the total number of NPs. Spectra were calculated for gaps of g = 1 nm (solid line) and g = 20 nm (dashed line) between neighboring NPs. The insets in A and B show the resonance maximum and the ratio of scattering and absorption efficiencies at the dipole SP mode for gaps of 1 and 20 nm as a function of NP number, respectively. The dotted horizontal line in the inset in B, QSCA/QABS = 1, is given as a reference to illustrate when scattering becomes more dominant than absorption.