Fig. 3
a Near-field distributions, energy flows (cyan arrows), and electrical filed stream lines (purple lines) corresponding to bonding modes (absorption spectra) for case 1 at λ res = 1.19 μm, for case 2 at λ res = 1.93 μm, for case 3 at λ res = 2.14 μm, and for case 4 at λ res = 2.36 μm, respectively. b Schematic charge densities corresponding to bonding modes of the cases 1–4