Open AccessSignificant optical force enhancements of nanostructure with balanced gain and loss
Author(s) -
Xiaoming Zhang,
Yuqi Peng,
Chern Lee,
Xinhong Chu,
Yanping Xiao,
Haiyan Wang,
Fazhi Xie,
Jianping Liu,
Yijun Yuan
Publication year - 2021
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.430719
Subject(s) - optical force , optical tweezers , physics , optics , polarization (electrochemistry) , molecular physics , materials science , chemistry
In this paper, we theoretically analyze the optical force between a pair of active and passive plasmonic core-shell nanoparticles (NPs). The optical force between the NPs can be either attractive or repulsive near the critical point while the passive dimer provides only attractive force. We reveal that the reversal of attractive or repulsive force is determined by the relative phase of electric dipole (ED) modes, which can be strongly affected by the gain and loss coefficient κ. Compared with the passive dimer with the same size, the active-passive dimer can exhibit a very high repulsive force (about two orders of magnitude) while remaining the same order magnitude attractive force when the value of coefficient is 0.345. Interestingly, we find that the position of the maximum repulsive force occurs near the critical point. We also investigate the influence of variations in geometrical parameters of the dimer and polarization angle on the force. Finally, the numerical results demonstrate that when the dimer is illuminated by a laser beam, the attractive and repulsive forces can also be achieved. The manipulation of optical force can find potential in optical sorting and transport of NPs.