The shaded boxes highlight the optical conditions for the OPFs. Here, ed, md, and eq are the complex amplitudes of the electric dipole, magnetic dipole, and electric quadrupole modes of the incoming light to the NP, respectively; See (or Sem) is the scattering coefficient consisting of electric dipole and electric quadrupole (or electric dipole and magnetic dipole) of the Lorenz-Mie scattering coefficient of the NP.
| Electric dipole-electric quadrupole interactions | ||
| Scattering coefficients of NP | Optical force | |
| Re(See) < 0 | Im(See) > 0 | |
| Amplitudes of multipole terms of incoming light to NP ed: electric dipole, eq: electric quadrupole | Fee < 0 | |
| when | ||
| when | ||
| Fee > 0 | ||
| Electric dipole-magnetic dipole interactions | ||
| Scattering coefficients of NP | Optical force | |
| Re(Sem) > 0 | Im(Sem) > 0 | |
| Amplitudes of multipole terms of incoming light to NP ed: electric dipole, md: magnetic dipole | Fem < 0 | |
| when | ||
| when | ||
| Fem > 0 | ||