%0 Journal Article
%T Controlled transportation of mesoscopic particles by enhanced spin orbit interaction of light in an optical trap
%A Basudev Roy
%A Nirmalya Ghosh
%A Subhasish Dutta Gupta
%A Prasanta K. Panigrahi
%A Soumyajit Roy
%A Ayan Banerjee
%J Physics
%D 2012
%I arXiv
%R 10.1103/PhysRevA.87.043823
%X We study the effects of the spin orbit interaction (SOI) of light in an optical trap and show that the propagation of the tightly focused trapping beam in a stratified medium can lead to significantly enhanced SOI. For a plane polarized incident beam the SOI manifests itself by giving rise to a strong anisotropic linear diattenuation effect which produces polarization-dependent off-axis high intensity side lobes near the focal plane of the trap. Single micron-sized asymmetric particles can be trapped in the side lobes, and transported over circular paths by a rotation of the plane of input polarization. We demonstrate such controlled motion on single pea-pod shaped single soft oxometalate (SOM) particles of dimension around $1\times 0.5\mu$m over lengths up to $\sim$15 $\mu$m . The observed effects are supported by calculations of the intensity profiles based on a variation of the Debye-Wolf approach. The enhanced SOI could thus be used as a generic means of transporting mesoscopic asymmetric particles in an optical trap without the use of complex optical beams or changing the alignment of the beam into the trap.
%U http://arxiv.org/abs/1206.6518v3