In general, the optical binding force between identical particles is thought to be symmetric. However, we demonstrate analytically a counterintuitively asymmetric longitudinal optical binding force between two identical electric and magnetic dipolar dielectric particles. This homodimer is confined in two counterpropagating incoherent plane waves along the dimer's axis. The force consists of the electric dipolar, magnetic dipolar, and electric-magnetic dipolar coupling interactions. The combined effect of these interactions is markedly different than the expected behavior in the Rayleigh approximation. The asymmetric force is a result of the asymmetric forward and backward scattering of the particles due to the dipolar hybridization and coupling interactions. Consequently, it leads to a harmonic driving force on the pair, which decays with the interparticle distance to the first power. We show the rich nonequilibrium dynamics of the dimer and of the two particles impelled by the driving and binding forces and discuss the ranges of particle refractive index and size in which the asymmetric binding force arises. Our results open perspectives for nonequilibrium light-driven multiparticle transport and self-assembly.
|Journal||Physical Review A|
|Publication status||Published - 2022 Jul|
Bibliographical noteFunding Information:
This work was supported by the Jiaxing Science and Technology Project (Grant No. 2021AY10057). K.D. acknowledges support of the UK Engineering and Physical Sciences Research Council (Grant No. EP/P030017/1).
© 2022 American Physical Society.
All Science Journal Classification (ASJC) codes
- Atomic and Molecular Physics, and Optics