Figure 4

Quantitative mapping of the Quality factors and Dephasing times of individual plasmon modes in a single gold particle.

(a) Experimental EELS spectra from locations I–IV, showing three dominant plasmon modes in an irregularly-shaped gold cross. Before subtracting the background, the zero-loss peak (ZLP) maxima of the spectra were normalized. (b) The EELS spectrum from location III, showing an example of the fitting of three Lorentzians. The sum of the three Lorentzians and the EELS data are shifted vertically for clarity and their peak widths are shown. (c) Overlaid, colour-coded EELS maps from the three dominant plasmon modes, with in the legend their Q and T₂ values. On the EELS maps, the STEM annular dark field image of the nanocross is projected in grayscale⁴⁰. Locations I–IV are indicated on the map, 1–2 nm off the tip of the arms.