Stable Fano-like plasmonic resonance: its impact on the reversal of far- and near-field optical binding force

Hamim Mahmud Rivy,M R C Mahdy,Nabila Masud,Ziaur Rahman Jony,Saikat Chandra Das

Figure 7. The first two columns represent the near-field ((a)–(d)) extinction spectra and ((e)–(h)) binding force, and the next two columns represent the far-field ((i)–(l)) extinction spectra and ((m)–(p)) binding force for cube, cylinder, ring and spherical nanoparticle tetramers, respectively. Mie-range plasmonic tetramers are placed in a background medium of 1.50 refractive index. In our geometry, nanoparticles are placed at equal distances from the center. Thus, for our configuration ${{\boldsymbol{F}}}_{{\rm{b}}{\rm{i}}{\rm{n}}{\rm{d}}}=\,{{\boldsymbol{F}}}_{{\rm{b}}{\rm{i}}{\rm{n}}{\rm{d}}1}={{\boldsymbol{F}}}_{{\rm{b}}{\rm{i}}{\rm{n}}{\rm{d}}2}.$ As a result, ${F}_{{\rm{b}}{\rm{i}}{\rm{n}}{\rm{d}}}$ represents the binding force between $N{P}_{1}$ and $N{P}_{3}$, and $N{P}_{2}$ and $N{P}_{4}.$ The positive value and the negative values of the binding forces, respectively, represent the attractive binding force and the repulsive binding force. Lorentz force components of the binding force are represented by the (${\rm{Del}}\,{{\rm{F}}}_{{\rm{Surf}}}$) surface force and (${\rm{Del}}\,{{\rm{F}}}_{{\rm{Bulk}}}$) bulk force.