Fig. 2: Near-field excitation of the doped nanoparticle by localized plasmonic fields.

Theoretical representations of the integrated electric field intensity distribution (a, at \({{\boldsymbol{\lambda }}}_{{\boldsymbol{exc}}}^{{\boldsymbol{ED}}}=532{\,\rm{nm}}\)) and of the integrated magnetic field intensity distribution (b, at \({{\boldsymbol{\lambda }}}_{{\boldsymbol{exc}}}^{{\boldsymbol{MD}}}=527.5{\,\rm{nm}}\)) in an XY plane beneath the aluminum nanodisk at a distance Z of 100 nm. The linear polarization of the excitation is as indicated in the inset of b. Normalized luminescence intensities collected while scanning the plasmonic nano-antenna excited at the wavelength of the ED transition (c, \({{\boldsymbol{\lambda }}}_{{\boldsymbol{exc}}}^{{\boldsymbol{ED}}}=532{\,\rm{nm}}\)) and the MD transition (d, \({{\boldsymbol{\lambda }}}_{{\boldsymbol{exc}}}^{{\boldsymbol{MD}}}=527.5{\,\rm{nm}}\)). The linear polarization used is shown in the inset of d. White circles are guides for the eyes showing the position of the nanoantenna, the gap and the border of the coated tip, the experimental images have a total size of 1.5 μm × 1.5 μm and consist of 50 × 50 pixels. Line cuts are presented for the theoretical field intensities e and the experimental luminescence signals f obtained from the distributions in a, b and c, d, respectively. Green lines correspond to line cuts at the ED wavelength, while blue lines correspond to the magnetic counterpart