Open AccessTailoring optical pulling force on gain coated nanoparticles with nonlocal effective medium theory
Author(s) -
Xiongheng Bian,
Dongliang Gao,
Lei Gao
Publication year - 2017
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.25.024566
Subject(s) - optical force , quantum nonlocality , fano resonance , plasmon , optics , surface plasmon resonance , wavelength , surface plasmon , optical tweezers , plasmonic nanoparticles , physics , permittivity , scattering , mie scattering , materials science , nanoparticle , light scattering , optoelectronics , dielectric , nanotechnology , quantum mechanics , quantum entanglement , quantum
We study the optical scattering force on the coated nanoparticles with gain core and nonlocal plasmonic shell in the long-wavelength limit, and demonstrate negative optical force acting on the nanoparticles near the symmetric and/or antisymmetric surface plasmon resonances. To understand the optical force behavior, we propose nonlocal effective medium theory to derive the equivalent permittivity for the coated nanoparticles with nonlocality. We show that the imaginary part of the equivalent permittivity is negative near the surface resonant wavelength, resulting in the negative optical force. The introduction of nonlocality may shift the resonant wavelength of the optical force, and strengthen the negative optical force. Two examples of Fano-like resonant scattering in such coated nanoparticles are considered, and Fano resonance-induced negative optical force is found too. Our findings could have some potential applications in plasmonics, nano-optical manipulation, and optical selection.