We report a dramatic enhancement of the lateral optical forces induced on electrically polarizable Rayleigh particles near hyperbolic and extremely anisotropic metasurfaces under simple plane wave illumination. Such enhancement is enabled by the interplay between the increased density of states provided by these structures and the out-of-plane polarization spin acquired by the particle.
The resulting giant lateral forces appear over a broad frequency range and may openunprecedented venues for routing, trapping, and assembling nanoparticles. PACS: 32.10.Dk, 42.25.Fx, 73.20.Mf, 78.67.Wj Light-induced forces have led to many exciting applications in nanotechnology and bioengineering by trapping, pushing, pulling, binding and manipulating nanoparticles and biological samples [1][2][3][4][5][6][7][8]. Recently, the emergence of nano-optical plasmonic configurations has been exploited to boost the strength of optical forces at the nano-scale by exciting surface plasmon polaritons (SPPs) [9][10][11][12], which are confined electromagnetic waves traveling along dielectricmetal interfaces [13]. In fact, illuminating with light an electric, non-magnetic, Rayleigh particle (with radius r < λ 0 /20, being 0 the wavelength) located above a metallic surface like gold or
Abstract-The electromagnetic force acting on a Rayleigh particle placed in a rectangular waveguide is studied. The particle is excited using the lowest order TE 10 mode. It is determined that the particle is laterally trapped at the high intensity region of the electric field and either pushed away from or pulled toward the light source. This push-pull phenomenon depends on whether the frequency of the light wave is above or below the cutoff frequency (i.e., the particle can be pushed or pulled by tuning the frequency). While conventional optical tweezers rely on a balance of scattering and gradient force in the propagation direction, the phenomenon predicted here switches between the two forces near the lowest cutoff in a waveguide.
Optical trapping and manipulation of dielectric particles on the surface of a dielectric prism using TE plane waves are demonstrated in the Rayleigh scattering regime. The interference of four counter propagating evanescent waves forms a standing wave on the planar surface and the trapping is realized based on the gradient force. Two mirrors are used to manipulate the trapped particles in any arbitrary direction on the surface. The required trapping potential and the irradiance within the Rayleigh scattering regime are computed. A hypothesis is developed to pull the particles at a maximum force toward the surface for further demonstration of this configuration. The standing wave on the surface of the prism using TE Gaussian beams are demonstrated for practical illustration of this study.
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