Open AccessTheory of dielectric micro-sphere dynamics in a dual-beam optical trap
Author(s) -
Motoharu Kawano,
J.T. Blakely,
Reuven Gordon,
David Sinton
Publication year - 2008
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.16.009306
Subject(s) - optical tweezers , multipole expansion , physics , optics , oscillation (cell signaling) , optical force , beam (structure) , maxwell stress tensor , dielectric , trapping , mie scattering , computational physics , classical mechanics , cauchy stress tensor , quantum mechanics , light scattering , ecology , genetics , scattering , biology
We investigate the dynamics of an array of polystyrene micron-sized spheres in a dual-beam fiber-optic trap. Experimental results show non-uniform equilibrium particle spacing and spontaneous self-sustained oscillation for large particle numbers. Results are analyzed with a Maxwell- Stress Tensor method using the Generalized Multipole Technique, where hydrodynamic interactions between particles are included. The theoretical analysis matches well with the experimentally observed equilibrium particle spacing. The theory shows that an offset in the trapping beams is the underlying mechanism for the oscillations and influences both the oscillation frequency and the damping rate for oscillations. The theory presented is of general interest to other systems involving multi-particle optical interactions.