Optical binding and the influence of beam structure

An optically induced interparticle potential, applicable to particles of any shape, is derived in a formulation that accommodates the effects of beam structure. The theory allows the consideration of optical binding interactions in beams of spatially varying irradiance and polarization. Results of specific calculations are exhibited for spherical particles in linearly, circularly, and radially polarized Laguerre-Gaussian beams, leading to the identification of several possible optically induced particle arrangements. The patterning of these optically induced structures is shown to have an identical dependence on the optical wavenumber and spot size at the beam waist. (C) 2008 Optical Society of America