Geometric configurations and perturbative mechanisms in optical binding

Optical binding is a phenomenon that is exhibited by micro-and nano-particle systems, suitably irradiated with offresonance laser light. Recent quantum electrodynamical studies on optically induced inter-particle potential energy surfaces have revealed unexpected features of considerable intricacy. When several particles are present, multi-particle binding effects can commonly result in the formation of a variety of geometrical assemblies. The exploitation of these features presents a host of opportunities for the optical fabrication of nanoscale structures, based on the fine control of attractive and repulsive forces, and the torques that operate on particle pairs. This paper reports the results of a preliminary analysis of the structures formed by optically driven self-assembly, and the three-dimensional symmetry of energetically favored forms. In systems where permanent dipole moments are present, optical binding may also be influenced by a static interaction mechanism. The possible influence of such effects on assembly formation is also explored, and consideration is given to the possible departures from such symmetry which might then be anticipated