Three-dimensional optical confinement of micron-sized metal particles and the decoupling of the spin and orbital angular momentum within an optical spanner

O'Neil, A.T. and Padgett, M. (2000) Three-dimensional optical confinement of micron-sized metal particles and the decoupling of the spin and orbital angular momentum within an optical spanner. Optics Communications, 185(1-3), 139 -143. (doi: 10.1016/S0030-4018(00)00989-5)

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Publisher's URL: http://dx.doi.org/10.1016/S0030-4018(00)00989-5

Abstract

We report a new mechanism for trapping metallic particles in inverted optical tweezers. The particles are loosely confined, in three dimensions, to an annular region just below the beam waist where gravity is counterbalanced by the scattering force. When using a Laguerre-Gaussian mode the trapping efficiency is improved and additionally we are able to observe an off-axis rotation of the particles around the beam circumference which is induced by the orbital angular momentum of the beam. Since there is no mechanism by which the spin angular momentum can contribute to the scattering force the spin and orbital angular momentum terms are decoupled and therefore the polarisation state does not influence the motion of the particles.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Padgett, Professor Miles
Authors: O'Neil, A.T., and Padgett, M.
Subjects:Q Science > QC Physics
College/School:College of Science and Engineering > School of Physics and Astronomy
Journal Name:Optics Communications
ISSN:0030-4018

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