Manipulation of metallic nanoparticle with evanescent vortex Bessel beam

Abstract

In this work, we propose a novel strategy to optically trap and manipulate metallic nanoparticles using evanescent vortex Bessel beam (EVBB). A versatile method is presented to generate evanescent Bessel beam with tunable optical angular momentum by focusing a radially polarized vortex beam onto a one-dimensional photonics band gap structure. The behavior of a metallic nanoparticle in the EVBB is numerically studied. We show that such particle can be stably trapped near the surface. The orbital angular momentum drives the metallic nanoparticle to orbit around the beam axis, and the direction of the orbital motion is controlled by the handedness of the helical phase front. The technique demonstrated in this work may open up new avenues for optical manipulation, and the non-contact tunable orbiting dynamics of the trapped particle may find important applications in higher resolution imaging techniques.

Trapping and manipulation of nanoparticles using multifocal optical vortex metalens

“…Due to strong scattering force and severe optical heating effect, trapping plasmonic particles do not always success, especially when the trapping wavelength is close to the resonance of the particle. Thanks to the advanced optical engineering, generation of optical fields with inhomogeneous spatial distribution in terms of phase, amplitude and polarization become possible, which are helpful to improve the performance of optical tweezers and realize novel optical micromanipulation techniques 6 – 9 . For example, negative scattering force has been reported for some Bessel beams 10 , 11 , enabling to trap plasmonic nanoparticle even under the resonant condition by tailoring the spatial distribution of the vectorial optical illumination 12 , 13 .…”

Near-field acoustic manipulation in a confined evanescent Bessel beam

“…As recently shown in plasmonics, the confinement of optical vortices 35 or of evanescent vortex Bessel beam 36 is a promising approach to achieve powerful optical spanners. Likewise, we believe that adding an azimuthal phase control of the excitation will generate higher order evanescent acoustic Bessel beam and acoustic vortices.…”

Controlled Mechanical Motions of Microparticles in Optical Tweezers

“…Unlike propagating fields used in conventional optical tweezers, the energy of evanescent field is spatially concentrated in the vicinity of the light source and extends from the interface up to several hundred nanometers away in distance. As the intensity distribution of light decays rapidly with a length far smaller than half the wavelength (the scale of conventional optical trap) this generates a very strong gradient force enabling to capture nano-scale particles [ 82 , 83 , 84 ]. As shown in Figure 7 a, a well-designed subwavelength waveguide slot illuminated by laser beam can excite a strongly localized field at its center.…”