Spontaneous symmetry breaking and circulation by optically bound microparticle chains in Gaussian beam traps.

Abstract

It has been known for some time that simple “optically bound” chains of dielectric microparticles can form in a counter propagating Gaussian beam optical trap. Here we report experimental observations of more complex trapped states, which do not reflect the underlying symmetry of the optical beam trap they are confined in. We discuss both stationary off-axis trapping and dynamic motion. We confirm the results using a rigorous Mie scattering model and also give a physical explanation for these static and dynamic off-axis trapped states.