Configurable three-dimensional optical cage generated from cylindrical vector beams

We propose a new approach to generate a controllable three-dimensional (3D) optical cage by double-mode cylindrical vector beam in the vicinity of focus, by controlling the polarization state of beam. The simulation results show that the 3D optical cage of spheroid surface shape with a sharp dark region surrounded by a uniform optical barrier with a maximum deviation of 2% is achieved. The finite-difference time-domain calculation of optical force validates that such a kind of 3D optical cage has the trapping capability of the low-refractive-index particles with the size being much smaller than the light wavelength. (c) 2009 Elsevier B.V. All rights reserved.