Morphology-dependent resonance of the optical forces on Mie particles in an Airy beam

Self Cite

In this paper, using an angular spectrum method, we develop an analytical theory for Airy surface plasmon wave excited in a classical Kretschmann setup. It is found that the center of an Airy surface plasmon polariton (SPP) wave has a giant positive lateral shift, and the sidelobes move forward along the surface. The intensity of the Airy SPP wave is greatly enhanced, the corresponding optical forces can be enhanced by more than one order of magnitude. Importantly, we show that the sidelobes of the Airy SPP beam can lead to the splitting of optical force spectra with the variation of incident angle, which is accompanied by strong oscillations emerging at the optimal metal layer thickness. Moreover, the effects of multiple scatterings of the Airy SPP wave between the particle and the metal layer are also discussed. The theoretical analysis could open up new perspectives for the applications of Airy beam in optical manipulation and surface-enhanced Raman scattering.

Section: Resultsmentioning

confidence: 99%

Enhanced and unusual angle-dependent optical forces exerted on Mie particles by Airy surface plasmon wave

Yang¹,

Xue²,

Li³

et al. 2016

Self Cite

“…In the above, we consider optical force exerted on the Ag particle by the Gaussian evanescent wave beam. Finally, we investigate the impacts of multiple scattering of this Gaussian evanescent wave between the Ag particle and the interface on the optical forces [36][37][38]. That this can be an issue is because the air-glass interface would induce Fresnel reflection upon the scattering light by the Ag particle, although this effect might not be strong due to small Fresnel reflection coefficients.…”

Section: Resultsmentioning

confidence: 99%

Fano resonance of the ultrasensitve optical force excited by Gaussian evanescent field

Yang¹,

Li²,

Li³

2015

Self Cite

In this paper, we study the angle-dependent Fano-like optical force spectra of plasmonic Ag nanoparticles, which exhibit extraordinary transformation from Lorentzian resonance to Fano resonance when excited by a Gaussian evanescent wave. We systematically analyze the behavior of this asymmetric scattering induced optical force under different conditions and find that this Fano interference-induced force is ultrasensitive to the excitation wavelength, incident angle and particle size, as well as the core–shell configuration, which could be useful for wavelength- and angle-dependent size-selective optical manipulation. The origin of this Fano resonance is further identified as the interference between the two adjacent-order multipolar plasmonic modes excited in the Ag particle under the excitation of an inhomogeneously distributed evanescent field.

“…However, in a more realistic situation, it is always necessary to consider particles whose diameters are much larger than 20 l , which are called Mie particles. The optical forces exerted on a Mie particle in the Airy evanescent field have been investigated in detail [29,30]. It is urgently necessary to establish the kinematic equations and simulate the motions of Mie particles.…”

Section: Introductionmentioning

confidence: 99%

Optical trapping and manipulation of Mie particles with Airy beam

Zhao

Zang

Tian

2016

In this paper we calculate the radiation forces and moving trajectories of Mie particles induced by 1D Airy beams using the plane wave spectrum method and arbitrary beam theory. Numerical results show that both the transverse and the longitudinal radiation forces are deeply dependent on the relative refractive index, radii and positions of the scattering particles illuminated by the Airy beam. Due to the radiation forces, Mie particles with different radii and initial positions can be dragged into the nearest main intensity lobes, and move along parabolic trajectories in the direction of the Poynting vector. At the ends of these trajectories, in the presence of Brownian force, the trapped scattering particles show irregular Brownian movement near their equilibrium positions. This characteristic property of Airy beams enables optical sorting to be used more easily in the colloidal and biological sciences.