Fano Resonance-Induced Negative Optical Scattering Force on Plasmonic Nanoparticles

Abstract

We demonstrate theoretically that Fano resonance can induce a negative optical scattering force acting on plasmonic nanoparticles in the visible light spectrum when an appropriate manipulating laser beam is adopted. Under the illumination of a zeroth-order Bessel beam, the plasmonic nanoparticle at its Fano resonance exhibits a much stronger forward scattering than backward scattering and consequently leads to a net longitudinal backward optical scattering force, termed Fano resonance-induced negative optical scattering force. The extinction spectra obtained based on the Mie theory show that the Fano resonance arises from the interference of simultaneously excited multipoles, which can be either a broad electric dipole mode and a narrow electric quadrupole mode, or a quadrupole and an octupole mode mediated by the broad electric dipole. Such Fano resonance-induced negative optical scattering force is demonstrated to occur for core-shell, homogeneous, and hollow metallic particles and can therefore be expected to be universal for many other nanostructures exhibiting Fano resonance, adding considerably to the flexibility of optical micromanipulation on the plasmonic nanoparticles. More interestingly, the flexible tunability of the Fano resonance by particle morphology opens up the possibility of tailoring the optical scattering force accordingly, offering an additional degree of freedom to optical selection and sorting of plasmonic nanoparticles.

Helical tractor beam: analytical solution of Rayleigh particle dynamics

“…In order to solve the general case given by Eqs. (8,9), it is necessary to uncouple the ψ(t) and z(t) variables. To do this, removing function H(t) from Eqs.…”

“…To do this, removing function H(t) from Eqs. (8,9) obtains that axial velocityż and angular velocityψ fulfill the following ellipse equation:…”

“…In this way, new advances in laser beam control have led to the experimental realization of tractor beams that can draw particles toward light sources [2][3][4][5][6][7]. Recently, it was pointed out that Fano resonance of a composite metallic nanoparticle can induce a negative pulling force [8]. Unlike conventional optical tweezers, which rely on adjusting the positions of intensity gradients to move objects, tractor beams can exert non-conservative pulling forces on particles by continuously dragging them towards the beam sources [9].…”

Precise Finite Difference Analysis of Lorentz Force Acting on Metal Nanoparticle Irradiated With Light

“…The Lorentz force is also crucial in fine manipulations of particles by light. Although light commonly pushes any object forward, but it is possible to induce backward and lateral forces under certain conditions of the light source and the medium of the particles [11][12][13].…”

Regulation of oxygen vacancy types on SnO2 (110) surface by external strain

“…[1][2][3][4][5] However, their properties depend heavily on the nanostructure morphology as well as electronic structure, which is modified by intrinsic oxygen vacancies (OVs). 6,7 Development of optoelectronic encompassing bulk SnO 2 materials, for instance, has been hampered by its dipole forbidden nature.…”