Transfer of orbital angular momentum to an optically trapped low-index particle

Abstract

We demonstrate the transfer of orbital angular momentum from a light beam to a trapped low-index particle. The particle is trapped in a dark annular region of a high-order Bessel beam and rotates around the beam axis due to scattering from the helical wave fronts of the light beam. A general theoretical geometrical optics model is developed that, applied to our specific situation, corroborates tweezing and transfer of orbital angular momentum to the low-index particle. Good quantitative agreement between theory and experiment for particle rotation rates is observed.

Spatial and temporal characterization of a Bessel beam produced using a conical mirror

“…Non-diffractive pump fields have been utilized in nonlinear optical processes like parametric down conversion [2,3,4,5,6,7], second [8,9,10,11], third [12], and higher-order harmonic generation [13]. Furthermore, the accuracy of optical tweezers [14,15,16], optical trapping [17,18,19,20,21] and the resolution of medical imaging [22,23] have been enhanced by the implementation of diffraction-free beams.…”

Polarization control of non-diffractive helical optical beams through subwavelength metallic apertures

“…carry orbital angular momentum [23]. The combination of these non-diffractive and singular properties might have interesting implications for imaging techniques [24]- [26], superresolution techniques [27], quantum optics [28] and optical trapping [29,30]. Furthermore, with annular concentric rings, SPs are resonantly excited on the grating.…”

Transfer of Orbital Angular Momentum from an Optical Vortex Beam to a Nanoparticle

“…A decoupling of spin and orbital angular momentum has been shown in optical tweezers where a particle placed off-axis may traverse the circumference of a Laguerre-Gaussian or higher order Bessel beam yet rotate on its axis due to spin angular momentum [17,18]. Further studies have been performed in Bessel light modes [19] where OAM has been transferred to low index particles [20]: these are confined to the dark region of the light field. The studies of trapped objects has gone further in this respect with new reverse rotation effects seen at air-water interfaces [21].…”