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 1. (a)–(d) Schematic diagrams of our generalized tetramer configuration for cube, cylinder, ring and spherical nanoparticles, respectively. Here, distinctly shaped plasmonic nanoparticle tetramers are half immersed in an inhomogeneous dielectric interface. The nanoparticles placed at the ‘−x’, ‘−y’, ‘x’ and ‘y’ positions are considered as $N{P}_{1},$ $N{P}_{2},$ $N{P}_{3},$ and $N{P}_{4}$, respectively. ${F}_{1},$ ${F}_{2},$ ${F}_{3}$ and ${F}_{4}$ represent the optical force on $N{P}_{1},$ $N{P}_{2},$ $N{P}_{3}$ and $N{P}_{4}.$ F-F represents the face to face binding force between $N{P}_{1}$ and $N{P}_{3}$ and $N{P}_{2}$ and $N{P}_{4}.$ Here, ${d}_{x}\,$and ${d}_{y}$ represent the surface to surface distance between the nanoparticles placed at the x-axis and y-axis. In our cases ${d}_{x}={d}_{y},$ which indicates that nanoparticles are placed at equal distances from the center. E-E represents the edge to edge optical binding force, which acts through the edge of the nanoparticles.