Optical Trapping Forces on Non-Spherical Particles in Fluid Flows

Abstract

The optical stability of particles above a waveguide surface depends on the forces induced by fluid drag and the electromagnetic field. The optical trapping forces on non-spherical particles were examined for various flow conditions. A three-dimensional finite element method was employed to calculate the electromagnetic field and the fluid flow. It was found that the stability of non-spherical particles is significantly affected by the fluid velocity and the orientation of the particles. The downward trapping force meant that non-spherical particles are more stable at higher Reynolds numbers. The length of the particle in the transverse direction also had a significant impact on particle stability. The present model was tested against previously reported results. © 2012 Copyright Taylor and Francis Group, LLC.