Multiple optical trapping and binding: new routes to self-assembly

The impact of optical forces in the physical and biological sciences now extends from familiar uses in trapping to more recent concepts of forces and torques enabling the manipulation of objects ranging in size from biological cells down to a single atom. These mechanical effects of optical fields have profound and far-reaching consequences, and attention is increasingly focused upon the opportunities for the non-contact assembly of particles into specific geometries. The present overview focuses on the two aspects of multiparticle trapping and optical binding. These can broadly be grouped as methods based on light-mediated inter-particle interactions, offering potential for the organisation of large numbers of micro-or nano-particles using optical forces alone.