Fig. 1. AFM and near-field fourth-order signal images of NPG and G@NPG

Fig. 2. Height contours from AFM images and intensities from fourth-order near-field images of NPG and G@NPG at the delineated lines in Fig. 1

Fig. 3. Numerically calculated surface electric field intensity distributions for NPG and G@NPG

Fig. 4. Absorption spectra of graphene, NPG, and G@NPG obtained by numerical calculation

Fig. 5. Numerically calculated absorption spectra of NP and G@NP at different particle diameters